android原始碼解析--AlertDialog及AlertDialog.Builder

傲慢的上校發表於2012-11-25

   昨天3點睡的,今天8點起,竟然不是太困,我現在睡眠質量太好了嗎?但是頭稍微有點沉,今天突然陰天,感覺有些不爽,昨天收拾衣服時突然發現,少了一件襯衫,有點納悶。

昨天晚上弄到很晚,簡單的看了下Dialog的原始碼,說要分析下建造者模式,在dialog裡面的應用其實是在AlertDialog中。


按照慣例,先看類說明:

A subclass of Dialog that can display one, two or three buttons. If you only want to display a String in this dialog box, use the setMessage() method. If you want to display a more complex view, look up the FrameLayout called "custom" and add your view to it:

 FrameLayout fl = (FrameLayout) findViewById(android.R.id.custom);
 fl.addView(myView, new LayoutParams(MATCH_PARENT, WRAP_CONTENT));
 
The AlertDialog class takes care of automatically setting WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM for you based on whether any views in the dialog return true from View.onCheckIsTextEditor(). Generally you want this set for a Dialog without text editors, so that it will be placed on top of the current input method UI. You can modify this behavior by forcing the flag to your desired mode after calling onCreate(Bundle).

一個可以顯示一個、二個或者三個按鈕的Dialog,如果只是想在對話方塊窗體上顯示一個String字串,使用SetMessage方法。如果想要顯示一些複雜的檢視,可以自定義然後新增自己的檢視如下:

FrameLayout fl = (FrameLayout) findViewById(android.R.id.custom);
 fl.addView(myView, new LayoutParams(MATCH_PARENT, WRAP_CONTENT));

在Dialog中不論你任何一個檢視的View.onCheckIsTextEditor方法返回true,AlertDialog類會自動的為其設定WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM這個標誌。一般情況下,如果一個Dialog中沒有文字編輯,需要手動設定該標誌,這樣Dialog就會顯示在當前輸入法的上面。在呼叫onCreate方法後,可以通過設定標誌使其達到想要的效果。

接著看全域性變數:

public class AlertDialog extends Dialog implements DialogInterface {
    private AlertController mAlert;

    /**
     * Special theme constant for {@link #AlertDialog(Context, int)}: use
     * the traditional (pre-Holo) alert dialog theme.
     */
    public static final int THEME_TRADITIONAL = 1;
    
    /**
     * Special theme constant for {@link #AlertDialog(Context, int)}: use
     * the holographic alert theme with a dark background.
     */
    public static final int THEME_HOLO_DARK = 2;
    
    /**
     * Special theme constant for {@link #AlertDialog(Context, int)}: use
     * the holographic alert theme with a light background.
     */
    public static final int THEME_HOLO_LIGHT = 3;

    /**
     * Special theme constant for {@link #AlertDialog(Context, int)}: use
     * the device's default alert theme with a dark background.
     */
    public static final int THEME_DEVICE_DEFAULT_DARK = 4;

    /**
     * Special theme constant for {@link #AlertDialog(Context, int)}: use
     * the device's default alert theme with a dark background.
     */
    public static final int THEME_DEVICE_DEFAULT_LIGHT = 5;

一個alertController和透明、全黑、全亮、裝置預設黑色和裝置預設亮色5中主題。

看一下建構函式:

protected AlertDialog(Context context) {
        this(context, resolveDialogTheme(context, 0), true);
    }

    /**
     * Construct an AlertDialog that uses an explicit theme.  The actual style
     * that an AlertDialog uses is a private implementation, however you can
     * here supply either the name of an attribute in the theme from which
     * to get the dialog's style (such as {@link android.R.attr#alertDialogTheme}
     * or one of the constants {@link #THEME_TRADITIONAL},
     * {@link #THEME_HOLO_DARK}, or {@link #THEME_HOLO_LIGHT}.
     */
    protected AlertDialog(Context context, int theme) {
        this(context, theme, true);
    }

    AlertDialog(Context context, int theme, boolean createContextWrapper) {
        super(context, resolveDialogTheme(context, theme), createContextWrapper);
        mWindow.alwaysReadCloseOnTouchAttr();
        mAlert = new AlertController(getContext(), this, getWindow());
    }

    protected AlertDialog(Context context, boolean cancelable, OnCancelListener cancelListener) {
        super(context, resolveDialogTheme(context, 0));
        mWindow.alwaysReadCloseOnTouchAttr();
        setCancelable(cancelable);
        setOnCancelListener(cancelListener);
        mAlert = new AlertController(context, this, getWindow());
    }

其構造方法均為protected或者許可權更小的預設,所以我們不能在外部直接呼叫其構造方法初始化一個AlertDialog。而且第一個和第二個構造方法(自定義主題)都是呼叫個第三個構造方法,初始化了非常重要的AlertController類,而啟動呼叫了resolveDialogTheme方法:

static int resolveDialogTheme(Context context, int resid) {
        if (resid == THEME_TRADITIONAL) {
            return com.android.internal.R.style.Theme_Dialog_Alert;
        } else if (resid == THEME_HOLO_DARK) {
            return com.android.internal.R.style.Theme_Holo_Dialog_Alert;
        } else if (resid == THEME_HOLO_LIGHT) {
            return com.android.internal.R.style.Theme_Holo_Light_Dialog_Alert;
        } else if (resid == THEME_DEVICE_DEFAULT_DARK) {
            return com.android.internal.R.style.Theme_DeviceDefault_Dialog_Alert;
        } else if (resid == THEME_DEVICE_DEFAULT_LIGHT) {
            return com.android.internal.R.style.Theme_DeviceDefault_Light_Dialog_Alert;
        } else if (resid >= 0x01000000) {   // start of real resource IDs.
            return resid;
        } else {
            TypedValue outValue = new TypedValue();
            context.getTheme().resolveAttribute(com.android.internal.R.attr.alertDialogTheme,
                    outValue, true);
            return outValue.resourceId;
        }
    }

確定Dialog主題,像在第一個Dialog中就是使用的系統預設主題:

else {
            TypedValue outValue = new TypedValue();
            context.getTheme().resolveAttribute(com.android.internal.R.attr.alertDialogTheme,
                    outValue, true);
            return outValue.resourceId;
        }
alwaysReadCloseOnTouchAttr是一個抽象方法,然後初始化AlertController。在第四個構造方法中,加了一個是否可以取消和CancelListener回撥監聽。

    /**
     * Gets one of the buttons used in the dialog.
     * <p>
     * If a button does not exist in the dialog, null will be returned.
     * 
     * @param whichButton The identifier of the button that should be returned.
     *            For example, this can be
     *            {@link DialogInterface#BUTTON_POSITIVE}.
     * @return The button from the dialog, or null if a button does not exist.
     */
    public Button getButton(int whichButton) {
        return mAlert.getButton(whichButton);
    }
    
    /**
     * Gets the list view used in the dialog.
     *  
     * @return The {@link ListView} from the dialog.
     */
    public ListView getListView() {
        return mAlert.getListView();
    }
獲取dialog中使用的Button和ListView,可以看到,均是呼叫AlertController類的方法實現。

    @Override
    public void setTitle(CharSequence title) {
        super.setTitle(title);
        mAlert.setTitle(title);
    }

設定標題。

/**
     * @see Builder#setCustomTitle(View)
     */
    public void setCustomTitle(View customTitleView) {
        mAlert.setCustomTitle(customTitleView);
    }
設定一個自定義檢視為標題。

   public void setMessage(CharSequence message) {
        mAlert.setMessage(message);
    }

設定顯示的訊息。

    /**
     * Set the view to display in that dialog.
     */
    public void setView(View view) {
        mAlert.setView(view);
    }
    
    /**
     * Set the view to display in that dialog, specifying the spacing to appear around that 
     * view.
     *
     * @param view The view to show in the content area of the dialog
     * @param viewSpacingLeft Extra space to appear to the left of {@code view}
     * @param viewSpacingTop Extra space to appear above {@code view}
     * @param viewSpacingRight Extra space to appear to the right of {@code view}
     * @param viewSpacingBottom Extra space to appear below {@code view}
     */
    public void setView(View view, int viewSpacingLeft, int viewSpacingTop, int viewSpacingRight,
            int viewSpacingBottom) {
        mAlert.setView(view, viewSpacingLeft, viewSpacingTop, viewSpacingRight, viewSpacingBottom);
    }

設定顯示的檢視,第二個方法裡面加上了邊距。

/**
     * Set a message to be sent when a button is pressed.
     * 
     * @param whichButton Which button to set the message for, can be one of
     *            {@link DialogInterface#BUTTON_POSITIVE},
     *            {@link DialogInterface#BUTTON_NEGATIVE}, or
     *            {@link DialogInterface#BUTTON_NEUTRAL}
     * @param text The text to display in positive button.
     * @param msg The {@link Message} to be sent when clicked.
     */
    public void setButton(int whichButton, CharSequence text, Message msg) {
        mAlert.setButton(whichButton, text, null, msg);
    }
    
    /**
     * Set a listener to be invoked when the positive button of the dialog is pressed.
     * 
     * @param whichButton Which button to set the listener on, can be one of
     *            {@link DialogInterface#BUTTON_POSITIVE},
     *            {@link DialogInterface#BUTTON_NEGATIVE}, or
     *            {@link DialogInterface#BUTTON_NEUTRAL}
     * @param text The text to display in positive button.
     * @param listener The {@link DialogInterface.OnClickListener} to use.
     */
    public void setButton(int whichButton, CharSequence text, OnClickListener listener) {
        mAlert.setButton(whichButton, text, listener, null);
    }

    /**
     * @deprecated Use {@link #setButton(int, CharSequence, Message)} with
     *             {@link DialogInterface#BUTTON_POSITIVE}.
     */
    @Deprecated
    public void setButton(CharSequence text, Message msg) {
        setButton(BUTTON_POSITIVE, text, msg);
    }
        
    /**
     * @deprecated Use {@link #setButton(int, CharSequence, Message)} with
     *             {@link DialogInterface#BUTTON_NEGATIVE}.
     */
    @Deprecated
    public void setButton2(CharSequence text, Message msg) {
        setButton(BUTTON_NEGATIVE, text, msg);
    }

    /**
     * @deprecated Use {@link #setButton(int, CharSequence, Message)} with
     *             {@link DialogInterface#BUTTON_NEUTRAL}.
     */
    @Deprecated
    public void setButton3(CharSequence text, Message msg) {
        setButton(BUTTON_NEUTRAL, text, msg);
    }

    /**
     * Set a listener to be invoked when button 1 of the dialog is pressed.
     * 
     * @param text The text to display in button 1.
     * @param listener The {@link DialogInterface.OnClickListener} to use.
     * @deprecated Use
     *             {@link #setButton(int, CharSequence, android.content.DialogInterface.OnClickListener)}
     *             with {@link DialogInterface#BUTTON_POSITIVE}
     */
    @Deprecated
    public void setButton(CharSequence text, final OnClickListener listener) {
        setButton(BUTTON_POSITIVE, text, listener);
    }

    /**
     * Set a listener to be invoked when button 2 of the dialog is pressed.
     * @param text The text to display in button 2.
     * @param listener The {@link DialogInterface.OnClickListener} to use.
     * @deprecated Use
     *             {@link #setButton(int, CharSequence, android.content.DialogInterface.OnClickListener)}
     *             with {@link DialogInterface#BUTTON_NEGATIVE}
     */
    @Deprecated
    public void setButton2(CharSequence text, final OnClickListener listener) {
        setButton(BUTTON_NEGATIVE, text, listener);
    }

    /**
     * Set a listener to be invoked when button 3 of the dialog is pressed.
     * @param text The text to display in button 3.
     * @param listener The {@link DialogInterface.OnClickListener} to use.
     * @deprecated Use
     *             {@link #setButton(int, CharSequence, android.content.DialogInterface.OnClickListener)}
     *             with {@link DialogInterface#BUTTON_POSITIVE}
     */
    @Deprecated
    public void setButton3(CharSequence text, final OnClickListener listener) {
        setButton(BUTTON_NEUTRAL, text, listener);
    }

後面的六個方法都被Deprecated掉,不用看了,第一個方法裡面設定某個Button(DialogInterface裡面的BUTTON_POSITIVE、BUTTON_NEGATIVE、BUTTON_NEUTRAL三個中的一個)被點選以後傳送的訊息,有可能是,第二個方法裡面為其中的一個Button設定點選響應監聽。

    /**
     * Set resId to 0 if you don't want an icon.
     * @param resId the resourceId of the drawable to use as the icon or 0
     * if you don't want an icon.
     */
    public void setIcon(int resId) {
        mAlert.setIcon(resId);
    }
    
    public void setIcon(Drawable icon) {
        mAlert.setIcon(icon);
    }

    /**
     * Set an icon as supplied by a theme attribute. e.g. android.R.attr.alertDialogIcon
     *
     * @param attrId ID of a theme attribute that points to a drawable resource.
     */
    public void setIconAttribute(int attrId) {
        TypedValue out = new TypedValue();
        mContext.getTheme().resolveAttribute(attrId, out, true);
        mAlert.setIcon(out.resourceId);
    }

設定頭部圖示。

public void setInverseBackgroundForced(boolean forceInverseBackground) {
        mAlert.setInverseBackgroundForced(forceInverseBackground);
    }

設定AlertDialog後面的窗體是否能夠獲得焦點(能不能響應使用者操作觸發的事件)

   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mAlert.installContent();
    }

onCreate方法,初始化AlertController。

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (mAlert.onKeyDown(keyCode, event)) return true;
        return super.onKeyDown(keyCode, event);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (mAlert.onKeyUp(keyCode, event)) return true;
        return super.onKeyUp(keyCode, event);
    }

按鍵事件,如果AlertController不處理則交給父類Dialog處理。


在上面AlertDialog的的各種設定方法,均是呼叫AlertController類中的方法實現,請參考android原始碼淺析--AlertController

下面就是Builder類了,它是AlertDialog中的內部類:

public static class Builder {
        private final AlertController.AlertParams P;
        private int mTheme;
        
        /**
         * Constructor using a context for this builder and the {@link AlertDialog} it creates.
         */
        public Builder(Context context) {
            this(context, resolveDialogTheme(context, 0));
        }

        /**
         * Constructor using a context and theme for this builder and
         * the {@link AlertDialog} it creates.  The actual theme
         * that an AlertDialog uses is a private implementation, however you can
         * here supply either the name of an attribute in the theme from which
         * to get the dialog's style (such as {@link android.R.attr#alertDialogTheme}
         * or one of the constants
         * {@link AlertDialog#THEME_TRADITIONAL AlertDialog.THEME_TRADITIONAL},
         * {@link AlertDialog#THEME_HOLO_DARK AlertDialog.THEME_HOLO_DARK}, or
         * {@link AlertDialog#THEME_HOLO_LIGHT AlertDialog.THEME_HOLO_LIGHT}.
         */
        public Builder(Context context, int theme) {
            P = new AlertController.AlertParams(new ContextThemeWrapper(
                    context, resolveDialogTheme(context, theme)));
            mTheme = theme;
        }

其全域性變數為一個AlertController的引數和一個主題。其構造方法為初始化兩個引數。注意theme這個引數,可以傳入一個自定義的主體,設定如顯示文字大小顏色等。

 /**
         * Returns a {@link Context} with the appropriate theme for dialogs created by this Builder.
         * Applications should use this Context for obtaining LayoutInflaters for inflating views
         * that will be used in the resulting dialogs, as it will cause views to be inflated with
         * the correct theme.
         *
         * @return A Context for built Dialogs.
         */
        public Context getContext() {
            return P.mContext;
        }

        為Dialog返回一個在Builder建立時有其對應主題的Context。程式會使用這個Context去獲取LayoutInflater去載入(填充?inflate怎麼翻譯才好呢?如有好的見解,請在下面留言多多指教)一個用於顯示在正在生成的dialog的使用正確主題的檢視。

        /**
         * Set the title using the given resource id.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setTitle(int titleId) {
            P.mTitle = P.mContext.getText(titleId);
            return this;
        }
        
        /**
         * Set the title displayed in the {@link Dialog}.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setTitle(CharSequence title) {
            P.mTitle = title;
            return this;
        }
        
        /**
         * Set the title using the custom view {@code customTitleView}. The
         * methods {@link #setTitle(int)} and {@link #setIcon(int)} should be
         * sufficient for most titles, but this is provided if the title needs
         * more customization. Using this will replace the title and icon set
         * via the other methods.
         * 
         * @param customTitleView The custom view to use as the title.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setCustomTitle(View customTitleView) {
            P.mCustomTitleView = customTitleView;
            return this;
        }

設定標題,第三個使用搞一個自定義檢視作為標題,然後注意這裡的返回值都是其自身。

        /**
         * Set the message to display using the given resource id.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setMessage(int messageId) {
            P.mMessage = P.mContext.getText(messageId);
            return this;
        }
        
        /**
         * Set the message to display.
          *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setMessage(CharSequence message) {
            P.mMessage = message;
            return this;
        }

設定顯示文字內容。

/**
         * Set the resource id of the {@link Drawable} to be used in the title.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setIcon(int iconId) {
            P.mIconId = iconId;
            return this;
        }
        
        /**
         * Set the {@link Drawable} to be used in the title.
          *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setIcon(Drawable icon) {
            P.mIcon = icon;
            return this;
        }

        /**
         * Set an icon as supplied by a theme attribute. e.g. android.R.attr.alertDialogIcon
         *
         * @param attrId ID of a theme attribute that points to a drawable resource.
         */
        public Builder setIconAttribute(int attrId) {
            TypedValue out = new TypedValue();
            P.mContext.getTheme().resolveAttribute(attrId, out, true);
            P.mIconId = out.resourceId;
            return this;
        }

設定頭部圖示。

       /**
         * Set a listener to be invoked when the positive button of the dialog is pressed.
         * @param textId The resource id of the text to display in the positive button
         * @param listener The {@link DialogInterface.OnClickListener} to use.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setPositiveButton(int textId, final OnClickListener listener) {
            P.mPositiveButtonText = P.mContext.getText(textId);
            P.mPositiveButtonListener = listener;
            return this;
        }
        
        /**
         * Set a listener to be invoked when the positive button of the dialog is pressed.
         * @param text The text to display in the positive button
         * @param listener The {@link DialogInterface.OnClickListener} to use.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setPositiveButton(CharSequence text, final OnClickListener listener) {
            P.mPositiveButtonText = text;
            P.mPositiveButtonListener = listener;
            return this;
        }

設定確定按鈕,在這裡可以看到,基本上都是設定AlertController.AlertParams P的值。以後會看一下AlertController這個類。

/**
         * Set a listener to be invoked when the negative button of the dialog is pressed.
         * @param textId The resource id of the text to display in the negative button
         * @param listener The {@link DialogInterface.OnClickListener} to use.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setNegativeButton(int textId, final OnClickListener listener) {
            P.mNegativeButtonText = P.mContext.getText(textId);
            P.mNegativeButtonListener = listener;
            return this;
        }
        
        /**
         * Set a listener to be invoked when the negative button of the dialog is pressed.
         * @param text The text to display in the negative button
         * @param listener The {@link DialogInterface.OnClickListener} to use.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setNegativeButton(CharSequence text, final OnClickListener listener) {
            P.mNegativeButtonText = text;
            P.mNegativeButtonListener = listener;
            return this;
        }

設定取消按鈕,裡面都有一個回撥監聽,當按鈕被按下時,可以自定義一些事件。

        /**
         * Set a listener to be invoked when the neutral button of the dialog is pressed.
         * @param textId The resource id of the text to display in the neutral button
         * @param listener The {@link DialogInterface.OnClickListener} to use.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setNeutralButton(int textId, final OnClickListener listener) {
            P.mNeutralButtonText = P.mContext.getText(textId);
            P.mNeutralButtonListener = listener;
            return this;
        }
        
        /**
         * Set a listener to be invoked when the neutral button of the dialog is pressed.
         * @param text The text to display in the neutral button
         * @param listener The {@link DialogInterface.OnClickListener} to use.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setNeutralButton(CharSequence text, final OnClickListener listener) {
            P.mNeutralButtonText = text;
            P.mNeutralButtonListener = listener;
            return this;
        }

設定中立按鈕。

        /**
         * Sets whether the dialog is cancelable or not.  Default is true.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setCancelable(boolean cancelable) {
            P.mCancelable = cancelable;
            return this;
        }

設定Dialog是否可以被取消,預設為true。

        /**
         * Sets the callback that will be called if the dialog is canceled.
         * @see #setCancelable(boolean)
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setOnCancelListener(OnCancelListener onCancelListener) {
            P.mOnCancelListener = onCancelListener;
            return this;
        }

為dialog設定一個取消時的回撥監聽。
        /**
         * Sets the callback that will be called if a key is dispatched to the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setOnKeyListener(OnKeyListener onKeyListener) {
            P.mOnKeyListener = onKeyListener;
            return this;
        }
設一個按鍵監聽,當dialog中的按鍵被按下時,會回撥監聽器中方法。

/**
         * Set a list of items to be displayed in the dialog as the content, you will be notified of the
         * selected item via the supplied listener. This should be an array type i.e. R.array.foo
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setItems(int itemsId, final OnClickListener listener) {
            P.mItems = P.mContext.getResources().getTextArray(itemsId);
            P.mOnClickListener = listener;
            return this;
        }
        
        /**
         * Set a list of items to be displayed in the dialog as the content, you will be notified of the
         * selected item via the supplied listener.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setItems(CharSequence[] items, final OnClickListener listener) {
            P.mItems = items;
            P.mOnClickListener = listener;
            return this;
        }

設定顯示在Dialog中的Item列表和當item被點選時響應的監聽器。

        /**
         * Set a list of items, which are supplied by the given {@link ListAdapter}, to be
         * displayed in the dialog as the content, you will be notified of the
         * selected item via the supplied listener.
         * 
         * @param adapter The {@link ListAdapter} to supply the list of items
         * @param listener The listener that will be called when an item is clicked.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setAdapter(final ListAdapter adapter, final OnClickListener listener) {
            P.mAdapter = adapter;
            P.mOnClickListener = listener;
            return this;
        }

設定一個由ListAdapter提供內容的item列表作為顯示在對話方塊的內容,當item被選擇的時候會有一個回撥監聽。

/**
         * Set a list of items, which are supplied by the given {@link Cursor}, to be
         * displayed in the dialog as the content, you will be notified of the
         * selected item via the supplied listener.
         * 
         * @param cursor The {@link Cursor} to supply the list of items
         * @param listener The listener that will be called when an item is clicked.
         * @param labelColumn The column name on the cursor containing the string to display
         *          in the label.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setCursor(final Cursor cursor, final OnClickListener listener,
                String labelColumn) {
            P.mCursor = cursor;
            P.mLabelColumn = labelColumn;
            P.mOnClickListener = listener;
            return this;
        }

設定一個由Cursor提供內容的item列表作為顯示在對話方塊的內容,當item被選擇的時候會有一個回撥監聽。lableColumn為Cursor中顯示在文字標籤上的列名。

        /**
         * Set a list of items to be displayed in the dialog as the content,
         * you will be notified of the selected item via the supplied listener.
         * This should be an array type, e.g. R.array.foo. The list will have
         * a check mark displayed to the right of the text for each checked
         * item. Clicking on an item in the list will not dismiss the dialog.
         * Clicking on a button will dismiss the dialog.
         * 
         * @param itemsId the resource id of an array i.e. R.array.foo
         * @param checkedItems specifies which items are checked. It should be null in which case no
         *        items are checked. If non null it must be exactly the same length as the array of
         *        items.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setMultiChoiceItems(int itemsId, boolean[] checkedItems, 
                final OnMultiChoiceClickListener listener) {
            P.mItems = P.mContext.getResources().getTextArray(itemsId);
            P.mOnCheckboxClickListener = listener;
            P.mCheckedItems = checkedItems;
            P.mIsMultiChoice = true;
            return this;
        }
        
        /**
         * Set a list of items to be displayed in the dialog as the content,
         * you will be notified of the selected item via the supplied listener.
         * The list will have a check mark displayed to the right of the text
         * for each checked item. Clicking on an item in the list will not
         * dismiss the dialog. Clicking on a button will dismiss the dialog.
         * 
         * @param items the text of the items to be displayed in the list.
         * @param checkedItems specifies which items are checked. It should be null in which case no
         *        items are checked. If non null it must be exactly the same length as the array of
         *        items.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setMultiChoiceItems(CharSequence[] items, boolean[] checkedItems, 
                final OnMultiChoiceClickListener listener) {
            P.mItems = items;
            P.mOnCheckboxClickListener = listener;
            P.mCheckedItems = checkedItems;
            P.mIsMultiChoice = true;
            return this;
        }
        
        /**
         * Set a list of items to be displayed in the dialog as the content,
         * you will be notified of the selected item via the supplied listener.
         * The list will have a check mark displayed to the right of the text
         * for each checked item. Clicking on an item in the list will not
         * dismiss the dialog. Clicking on a button will dismiss the dialog.
         * 
         * @param cursor the cursor used to provide the items.
         * @param isCheckedColumn specifies the column name on the cursor to use to determine
         *        whether a checkbox is checked or not. It must return an integer value where 1
         *        means checked and 0 means unchecked.
         * @param labelColumn The column name on the cursor containing the string to display in the
         *        label.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setMultiChoiceItems(Cursor cursor, String isCheckedColumn, String labelColumn, 
                final OnMultiChoiceClickListener listener) {
            P.mCursor = cursor;
            P.mOnCheckboxClickListener = listener;
            P.mIsCheckedColumn = isCheckedColumn;
            P.mLabelColumn = labelColumn;
            P.mIsMultiChoice = true;
            return this;
        }

提供一個包含可以多選的listView的Dialog,設定一個多選監聽,當item被選中時,監聽回撥會被觸發。

        /**
         * Set a list of items to be displayed in the dialog as the content, you will be notified of
         * the selected item via the supplied listener. This should be an array type i.e.
         * R.array.foo The list will have a check mark displayed to the right of the text for the
         * checked item. Clicking on an item in the list will not dismiss the dialog. Clicking on a
         * button will dismiss the dialog.
         * 
         * @param itemsId the resource id of an array i.e. R.array.foo
         * @param checkedItem specifies which item is checked. If -1 no items are checked.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setSingleChoiceItems(int itemsId, int checkedItem, 
                final OnClickListener listener) {
            P.mItems = P.mContext.getResources().getTextArray(itemsId);
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mIsSingleChoice = true;
            return this;
        }
        
        /**
         * Set a list of items to be displayed in the dialog as the content, you will be notified of
         * the selected item via the supplied listener. The list will have a check mark displayed to
         * the right of the text for the checked item. Clicking on an item in the list will not
         * dismiss the dialog. Clicking on a button will dismiss the dialog.
         * 
         * @param cursor the cursor to retrieve the items from.
         * @param checkedItem specifies which item is checked. If -1 no items are checked.
         * @param labelColumn The column name on the cursor containing the string to display in the
         *        label.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setSingleChoiceItems(Cursor cursor, int checkedItem, String labelColumn, 
                final OnClickListener listener) {
            P.mCursor = cursor;
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mLabelColumn = labelColumn;
            P.mIsSingleChoice = true;
            return this;
        }
        
        /**
         * Set a list of items to be displayed in the dialog as the content, you will be notified of
         * the selected item via the supplied listener. The list will have a check mark displayed to
         * the right of the text for the checked item. Clicking on an item in the list will not
         * dismiss the dialog. Clicking on a button will dismiss the dialog.
         * 
         * @param items the items to be displayed.
         * @param checkedItem specifies which item is checked. If -1 no items are checked.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setSingleChoiceItems(CharSequence[] items, int checkedItem, final OnClickListener listener) {
            P.mItems = items;
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mIsSingleChoice = true;
            return this;
        } 
        
        /**
         * Set a list of items to be displayed in the dialog as the content, you will be notified of
         * the selected item via the supplied listener. The list will have a check mark displayed to
         * the right of the text for the checked item. Clicking on an item in the list will not
         * dismiss the dialog. Clicking on a button will dismiss the dialog.
         * 
         * @param adapter The {@link ListAdapter} to supply the list of items
         * @param checkedItem specifies which item is checked. If -1 no items are checked.
         * @param listener notified when an item on the list is clicked. The dialog will not be
         *        dismissed when an item is clicked. It will only be dismissed if clicked on a
         *        button, if no buttons are supplied it's up to the user to dismiss the dialog.
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setSingleChoiceItems(ListAdapter adapter, int checkedItem, final OnClickListener listener) {
            P.mAdapter = adapter;
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mIsSingleChoice = true;
            return this;
        }

設定一個含有單選列表的Dialog。設定一個單選監聽,當item被選中時,監聽回撥會被觸發。當item被點選的時候,dialog並不會消失,只有Button點選時,dialog才會消失,如果沒有button,只能使用者自己取消dialog。

        /**
         * Sets a listener to be invoked when an item in the list is selected.
         * 
         * @param listener The listener to be invoked.
         * @see AdapterView#setOnItemSelectedListener(android.widget.AdapterView.OnItemSelectedListener)
         *
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setOnItemSelectedListener(final AdapterView.OnItemSelectedListener listener) {
            P.mOnItemSelectedListener = listener;
            return this;
        }

設定列表item被點選時的回撥監聽。

/**
         * Set a custom view to be the contents of the Dialog. If the supplied view is an instance
         * of a {@link ListView} the light background will be used.
         *
         * @param view The view to use as the contents of the Dialog.
         * 
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setView(View view) {
            P.mView = view;
            P.mViewSpacingSpecified = false;
            return this;
        }
        
        /**
         * Set a custom view to be the contents of the Dialog, specifying the
         * spacing to appear around that view. If the supplied view is an
         * instance of a {@link ListView} the light background will be used.
         * 
         * @param view The view to use as the contents of the Dialog.
         * @param viewSpacingLeft Spacing between the left edge of the view and
         *        the dialog frame
         * @param viewSpacingTop Spacing between the top edge of the view and
         *        the dialog frame
         * @param viewSpacingRight Spacing between the right edge of the view
         *        and the dialog frame
         * @param viewSpacingBottom Spacing between the bottom edge of the view
         *        and the dialog frame
         * @return This Builder object to allow for chaining of calls to set
         *         methods
         *         
         * 
         * This is currently hidden because it seems like people should just
         * be able to put padding around the view.
         * @hide
         */
        public Builder setView(View view, int viewSpacingLeft, int viewSpacingTop,
                int viewSpacingRight, int viewSpacingBottom) {
            P.mView = view;
            P.mViewSpacingSpecified = true;
            P.mViewSpacingLeft = viewSpacingLeft;
            P.mViewSpacingTop = viewSpacingTop;
            P.mViewSpacingRight = viewSpacingRight;
            P.mViewSpacingBottom = viewSpacingBottom;
            return this;
        }

為dialog設定一個自定義的View作為顯示內容。

/**
         * Sets the Dialog to use the inverse background, regardless of what the
         * contents is.
         * 
         * @param useInverseBackground Whether to use the inverse background
         * 
         * @return This Builder object to allow for chaining of calls to set methods
         */
        public Builder setInverseBackgroundForced(boolean useInverseBackground) {
            P.mForceInverseBackground = useInverseBackground;
            return this;
        }

設定對話方塊後面的窗體是否能夠獲得焦點(能不能響應使用者操作觸發的事件)

/**
         * @hide
         */
        public Builder setRecycleOnMeasureEnabled(boolean enabled) {
            P.mRecycleOnMeasure = enabled;
            return this;
        }

設定是OnMeasure後否回收檢視。

       /**
         * Creates a {@link AlertDialog} with the arguments supplied to this builder. It does not
         * {@link Dialog#show()} the dialog. This allows the user to do any extra processing
         * before displaying the dialog. Use {@link #show()} if you don't have any other processing
         * to do and want this to be created and displayed.
         */
        public AlertDialog create() {
            final AlertDialog dialog = new AlertDialog(P.mContext, mTheme, false);
            P.apply(dialog.mAlert);
            dialog.setCancelable(P.mCancelable);
            if (P.mCancelable) {
                dialog.setCanceledOnTouchOutside(true);
            }
            dialog.setOnCancelListener(P.mOnCancelListener);
            if (P.mOnKeyListener != null) {
                dialog.setOnKeyListener(P.mOnKeyListener);
            }
            return dialog;
        }

建立一個dialog,這時dialog並沒有顯示出來。我們在外面不能通過new來例項化一個AlertDialog,只能通過Builder類的create來建立一個AlertDialog。

最後一個方法,顯示dialog:

        /**
         * Creates a {@link AlertDialog} with the arguments supplied to this builder and
         * {@link Dialog#show()}'s the dialog.
         */
        public AlertDialog show() {
            AlertDialog dialog = create();
            dialog.show();
            return dialog;
        }
    }



檢視更多原始碼內容:Android原始碼解析



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