墨香帶你學Launcher之(七)--小部件的載入、新增以及大小調節

墨香發表於2016-12-22

上一章墨香帶你學Launcher之(六)--拖拽我們介紹了Launcher的拖拽過程,涉及到的範圍比較廣,包括圖示的拖拽,桌面上CellLayout的拖拽,小部件的拖拽,以及跨不同部件的拖拽,設計思想非常巧妙,不過整個流程相對也比較好掌握,只要跟著上一章的流程自己多跟蹤幾遍基本就熟悉了。按照計劃本章我們繼續學習Launcher的Widget的載入、新增以及Widget的大小調節。

Widget的資料載入

其實我們在第二章墨香帶你學Launcher之(二)-資料載入流程介紹過Widget資料的載入,相對只是簡單的做了介紹,下面我們稍微講的詳細點。

我們知道Widget的資料載入開始在LauncherModel中的updateWidgetsModel方法中,我們看下程式碼:

    void updateWidgetsModel(boolean refresh) {
        PackageManager packageManager = mApp.getContext().getPackageManager();
        final ArrayList<Object> widgetsAndShortcuts = new ArrayList<Object>();
        widgetsAndShortcuts.addAll(getWidgetProviders(mApp.getContext(), refresh));
        Intent shortcutsIntent = new Intent(Intent.ACTION_CREATE_SHORTCUT);
        widgetsAndShortcuts.addAll(packageManager.queryIntentActivities(shortcutsIntent, 0));
        mBgWidgetsModel.setWidgetsAndShortcuts(widgetsAndShortcuts);
    }複製程式碼

上面程式碼我們可以看到是通過呼叫getWidgetProviders(mApp.getContext(), refresh)方法來獲取所有Widget的,程式碼:

public static List<LauncherAppWidgetProviderInfo> getWidgetProviders(Context context,
                                                                         boolean refresh) {
        ArrayList<LauncherAppWidgetProviderInfo> results =
                new ArrayList<LauncherAppWidgetProviderInfo>();
        try {
            synchronized (sBgLock) {
                if (sBgWidgetProviders == null || refresh) {
                    HashMap<ComponentKey, LauncherAppWidgetProviderInfo> tmpWidgetProviders
                            = new HashMap<>();
                    AppWidgetManagerCompat wm = AppWidgetManagerCompat.getInstance(context);
                    LauncherAppWidgetProviderInfo info;

                    List<AppWidgetProviderInfo> widgets = wm.getAllProviders();
                    for (AppWidgetProviderInfo pInfo : widgets) {
                        info = LauncherAppWidgetProviderInfo.fromProviderInfo(context, pInfo);
                        UserHandleCompat user = wm.getUser(info);
                        tmpWidgetProviders.put(new ComponentKey(info.provider, user), info);
                    }

                    Collection<CustomAppWidget> customWidgets = Launcher.getCustomAppWidgets().values();
                    for (CustomAppWidget widget : customWidgets) {
                        info = new LauncherAppWidgetProviderInfo(context, widget);
                        UserHandleCompat user = wm.getUser(info);
                        tmpWidgetProviders.put(new ComponentKey(info.provider, user), info);
                    }
                    // Replace the global list at the very end, so that if there is an exception,
                    // previously loaded provider list is used.
                    sBgWidgetProviders = tmpWidgetProviders;
                }
                results.addAll(sBgWidgetProviders.values());
                return results;
            }
        } catch (Exception e) {
            ...    
        }
    }複製程式碼

我們看到首先是初始化AppWidgetManagerCompat,我們之前介紹過帶有Compat的是相容元件,我們看看是怎麼相容的,

墨香帶你學Launcher之(七)--小部件的載入、新增以及大小調節

我們下面程式碼:

public static AppWidgetManagerCompat getInstance(Context context) {
        synchronized (sInstanceLock) {
            if (sInstance == null) {
                if (Utilities.ATLEAST_LOLLIPOP) {
                    sInstance = new AppWidgetManagerCompatVL(context.getApplicationContext());
                } else {
                    sInstance = new AppWidgetManagerCompatV16(context.getApplicationContext());
                }
            }
            return sInstance;
        }
    }複製程式碼

我們可以看到AppWidgetManagerCompat的初始化有兩個,一個是當Api版本高於21(包含21)時,用AppWidgetManagerCompatVL,低於21時用AppWidgetManagerCompatV16,這兩個有什麼不同,我們下面分析。

下面我們看如何獲取Widget列表物件:

List<AppWidgetProviderInfo> widgets = wm.getAllProviders();複製程式碼

getAllProviders()方法是一個抽象方法,所以我們看哪裡進行了複寫,

墨香帶你學Launcher之(七)--小部件的載入、新增以及大小調節

可以看到還是上面兩個相容類複寫了該方法,我們看這個兩個類中做了什麼處理,先看V16中的:

    @Override
    public List<AppWidgetProviderInfo> getAllProviders() {
        return mAppWidgetManager.getInstalledProviders();
    }複製程式碼

我們再看mAppWidgetManager這個是在哪裡初始化,

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
    @Override
    public boolean bindAppWidgetIdIfAllowed(int appWidgetId, AppWidgetProviderInfo info,
            Bundle options) {
        if (Utilities.ATLEAST_JB_MR1) {
            return mAppWidgetManager.bindAppWidgetIdIfAllowed(appWidgetId, info.provider, options);
        } else {
            return mAppWidgetManager.bindAppWidgetIdIfAllowed(appWidgetId, info.provider);
        }
    }複製程式碼

裡面有個if語句,我們可以看到當Api大於等於17時,呼叫第一個進行初始化,否則呼叫第二個方法進行初始化,這就是對不同手機版本做的相容。在我們寫App的時候如果遇到相似情況也可以這麼處理。

我們再看一下VL中的getAllProviders()方法:

    @Override
    public List<AppWidgetProviderInfo> getAllProviders() {
        ArrayList<AppWidgetProviderInfo> providers = new ArrayList<AppWidgetProviderInfo>();
        for (UserHandle user : mUserManager.getUserProfiles()) {
            providers.addAll(mAppWidgetManager.getInstalledProvidersForProfile(user));
        }
        return providers;
    }複製程式碼

和V16中的不一樣了,這裡面是通過for迴圈來獲取的,其中有個UserHandle,那麼在原始碼中給出的解釋是裝置中的每個使用者,個人理解應該是每個應用,每個應用會有0-N個Widget,也就是從每個應用中獲取每個應用的Widget列表。這樣for迴圈就可以獲取整個手機中所有應用的widget列表了。

再回到上面getWidgetProviders方法的程式碼中,我們接著看,接著for迴圈AppWidgetProviderInfo列表資訊,重構LauncherAppWidgetProviderInfo物件,這裡有點怪,為啥有了AppWidgetProviderInfo物件還要重構一個LauncherAppWidgetProviderInfo物件,我們知道在寫外掛的時候每個Widget都會有一個類繼承AppWidgetProvider,這樣才會有一個外掛,因此我們知道AppWidgetProviderInfo物件肯定是AppWidgetProvider的物件,那麼LauncherAppWidgetProviderInfo是什麼,我們接著看能不能找到答案,LauncherAppWidgetProviderInfo的初始化時通過

LauncherAppWidgetProviderInfo.fromProviderInfo(context, pInfo);複製程式碼

方法進行初始化的,我們再看LauncherAppWidgetProviderInfo又繼承AppWidgetProviderInfo,越來越怪,我們接著看fromProviderInfo(context, pInfo)方法:

public static LauncherAppWidgetProviderInfo fromProviderInfo(Context context,
            AppWidgetProviderInfo info) {
        Parcel p = Parcel.obtain();
        info.writeToParcel(p, 0);
        p.setDataPosition(0);
        LauncherAppWidgetProviderInfo lawpi = new LauncherAppWidgetProviderInfo(p);
        p.recycle();
        return lawpi;
    }複製程式碼

我們看到最後是通過new LauncherAppWidgetProviderInfo來生成一個LauncherAppWidgetProviderInfo物件,那麼這個物件建構函式中有什麼:

    public LauncherAppWidgetProviderInfo(Parcel in) {
        super(in);
        initSpans();
    }複製程式碼

這個建構函式呼叫了initSpans方法,我們接著追尋:

private void initSpans() {
        LauncherAppState app = LauncherAppState.getInstance();
        InvariantDeviceProfile idp = app.getInvariantDeviceProfile();

        // We only care out the cell size, which is independent of the the layout direction.
        Rect paddingLand = idp.landscapeProfile.getWorkspacePadding(false /* isLayoutRtl */);
        Rect paddingPort = idp.portraitProfile.getWorkspacePadding(false /* isLayoutRtl */);

        // Always assume we're working with the smallest span to make sure we
        // reserve enough space in both orientations.
        float smallestCellWidth = DeviceProfile.calculateCellWidth(Math.min(
                idp.landscapeProfile.widthPx - paddingLand.left - paddingLand.right,
                idp.portraitProfile.widthPx - paddingPort.left - paddingPort.right),
                idp.numColumns);
        float smallestCellHeight = DeviceProfile.calculateCellWidth(Math.min(
                idp.landscapeProfile.heightPx - paddingLand.top - paddingLand.bottom,
                idp.portraitProfile.heightPx - paddingPort.top - paddingPort.bottom),
                idp.numRows);

        // We want to account for the extra amount of padding that we are adding to the widget
        // to ensure that it gets the full amount of space that it has requested.
        Rect widgetPadding = AppWidgetHostView.getDefaultPaddingForWidget(
                app.getContext(), provider, null);
        spanX = Math.max(1, (int) Math.ceil(
                        (minWidth + widgetPadding.left + widgetPadding.right) / smallestCellWidth));
        spanY = Math.max(1, (int) Math.ceil(
                (minHeight + widgetPadding.top + widgetPadding.bottom) / smallestCellHeight));

        minSpanX = Math.max(1, (int) Math.ceil(
                (minResizeWidth + widgetPadding.left + widgetPadding.right) / smallestCellWidth));
        minSpanY = Math.max(1, (int) Math.ceil(
                (minResizeHeight + widgetPadding.top + widgetPadding.bottom) / smallestCellHeight));
    }複製程式碼

這段程式碼也不難,是為了算四個引數:spanX、spanY、minSpanX、minSpanY,看過我前面部落格的都知道這個spanX和spanY引數是什麼,其實這個LauncherAppWidgetProviderInfo物件比系統自帶的AppWidgetProviderInfo帶有的就是多了這幾個引數,也就是方便我們新增到桌面是計算佔用位置。

最後得到HashMap這個Widget集合,最後通過

mBgWidgetsModel.setWidgetsAndShortcuts(widgetsAndShortcuts);複製程式碼

將這個集合放到WidgetsModel中:

public void setWidgetsAndShortcuts(ArrayList<Object> rawWidgetsShortcuts) {
        ...
        HashMap<String, PackageItemInfo> tmpPackageItemInfos = new HashMap<>();

        // clear the lists.
        ...

        InvariantDeviceProfile idp = LauncherAppState.getInstance().getInvariantDeviceProfile();

        // add and update.
        for (Object o: rawWidgetsShortcuts) {
            String packageName = "";
            UserHandleCompat userHandle = null;
            ComponentName componentName = null;
            if (o instanceof LauncherAppWidgetProviderInfo) {
                LauncherAppWidgetProviderInfo widgetInfo = (LauncherAppWidgetProviderInfo) o;

                // Ensure that all widgets we show can be added on a workspace of this size
                int minSpanX = Math.min(widgetInfo.spanX, widgetInfo.minSpanX);
                int minSpanY = Math.min(widgetInfo.spanY, widgetInfo.minSpanY);
                if (minSpanX <= (int) idp.numColumns &&
                    minSpanY <= (int) idp.numRows) {
                    componentName = widgetInfo.provider;
                    packageName = widgetInfo.provider.getPackageName();
                    userHandle = mAppWidgetMgr.getUser(widgetInfo);
                } else {
                    ...
                    continue;
                }
            } else if (o instanceof ResolveInfo) {
                ResolveInfo resolveInfo = (ResolveInfo) o;
                componentName = new ComponentName(resolveInfo.activityInfo.packageName,
                        resolveInfo.activityInfo.name);
                packageName = resolveInfo.activityInfo.packageName;
                userHandle = UserHandleCompat.myUserHandle();
            }

            if (componentName == null || userHandle == null) {
                ...
                continue;
            }
            ...

            PackageItemInfo pInfo = tmpPackageItemInfos.get(packageName);
            ArrayList<Object> widgetsShortcutsList = mWidgetsList.get(pInfo);
            if (widgetsShortcutsList != null) {
                widgetsShortcutsList.add(o);
            } else {
                widgetsShortcutsList = new ArrayList<>();
                widgetsShortcutsList.add(o);
                pInfo = new PackageItemInfo(packageName);
                mIconCache.getTitleAndIconForApp(packageName, userHandle,
                        true /* userLowResIcon */, pInfo);
                pInfo.titleSectionName = mIndexer.computeSectionName(pInfo.title);
                mWidgetsList.put(pInfo, widgetsShortcutsList);
                tmpPackageItemInfos.put(packageName,  pInfo);
                mPackageItemInfos.add(pInfo);
            }
        }

        // 排序.
        ...
        }
    }複製程式碼

在這裡將不同應用的Widget放到同一個列表中然後在放到mWidgetsList中,以供應載入Widget列表。接著執行繫結過程,繫結過程我們在第三章墨香帶你學Launcher之(三)-繫結螢幕、圖示、資料夾和Widget介紹過,但是裡面還有些東西在這裡需要介紹一下,我們看原始碼知道其實Widget是通過介面卡放置到WidgetsRecyclerView裡面的,WidgetsRecyclerView是一個RecyclerView,而每個Widget檢視是一個WidgetCell,那麼WidgetCell是什麼,我們看WidgetsListAdapter介面卡,這個我們就不詳細介紹了,在裡面的onBindViewHolder方法中對WidgetCell進行了初始化,其中在裡面會調動下面方法:

widget.applyFromAppWidgetProviderInfo(info, mWidgetPreviewLoader);複製程式碼

我們看看這個方法:

 public void applyFromAppWidgetProviderInfo(LauncherAppWidgetProviderInfo info,
            WidgetPreviewLoader loader) {

        InvariantDeviceProfile profile =
                LauncherAppState.getInstance().getInvariantDeviceProfile();
        mInfo = info;
        // TODO(hyunyoungs): setup a cache for these labels.
        mWidgetName.setText(AppWidgetManagerCompat.getInstance(getContext()).loadLabel(info));
        int hSpan = Math.min(info.spanX, profile.numColumns);
        int vSpan = Math.min(info.spanY, profile.numRows);
        mWidgetDims.setText(String.format(mDimensionsFormatString, hSpan, vSpan));
        mWidgetPreviewLoader = loader;
    }複製程式碼

上面程式碼通過mWidgetName.setText顯示名字,通過mWidgetDims.setText顯示大小。最後給mWidgetPreviewLoader賦值,我們看到這個loader是從WidgetsListAdapter中傳遞進來的,在WidgetsListAdapter中,是通過LauncherAppState.getInstance().getWidgetCache()獲取的,其實這個loader是在LauncherAppState初始化的時候就初始化了。

在WidgetCell初始化後呼叫了widget.ensurePreview()方法:

 public void ensurePreview() {
        ...
        int[] size = getPreviewSize();
        mActiveRequest = mWidgetPreviewLoader.getPreview(mInfo, size[0], size[1], this);
    }複製程式碼

在這裡呼叫mWidgetPreviewLoader.getPreview方法:

    public PreviewLoadRequest getPreview(final Object o, int previewWidth,
            int previewHeight, WidgetCell caller) {
        String size = previewWidth + "x" + previewHeight;
        WidgetCacheKey key = getObjectKey(o, size);

        PreviewLoadTask task = new PreviewLoadTask(key, o, previewWidth, previewHeight, caller);
        task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
        return new PreviewLoadRequest(task);
    }複製程式碼

在這裡執行了一個非同步任務PreviewLoadTask,我們看一下這個非同步任務,首先看doInBackground方法:

...
preview = generatePreview(launcher, mInfo, unusedBitmap, mPreviewWidth, mPreviewHeight);
...複製程式碼

接著看generatePreview方法:

    Bitmap generatePreview(Launcher launcher, Object info, Bitmap recycle,
            int previewWidth, int previewHeight) {
        if (info instanceof LauncherAppWidgetProviderInfo) {
            return generateWidgetPreview(launcher, (LauncherAppWidgetProviderInfo) info,
                    previewWidth, recycle, null);
        } else {
            return generateShortcutPreview(launcher,
                    (ResolveInfo) info, previewWidth, previewHeight, recycle);
        }
    }複製程式碼

我們看到是生成一個Bitmap,然後呼叫generateWidgetPreview生成Bitmap:

public Bitmap generateWidgetPreview(Launcher launcher, LauncherAppWidgetProviderInfo info,
            int maxPreviewWidth, Bitmap preview, int[] preScaledWidthOut) {
        // Load the preview image if possible
        if (maxPreviewWidth < 0) maxPreviewWidth = Integer.MAX_VALUE;

        Drawable drawable = null;
        if (info.previewImage != 0) {
            // 獲取相對應的drawable
            drawable = mManager.loadPreview(info);
            ...
        }

        // Draw the scaled preview into the final bitmap
        int x = (preview.getWidth() - previewWidth) / 2;
        if (widgetPreviewExists) {
            drawable.setBounds(x, 0, x + previewWidth, previewHeight);
            drawable.draw(c);
        } else {
            ...
            for (int i = 0; i < spanX; i++, tx += tileW) {
                float ty = 0;
                for (int j = 0; j < spanY; j++, ty += tileH) {
                    dst.offsetTo(tx, ty);
                    c.drawBitmap(tileBitmap, src, dst, p);
                }
            }
            ...
            try {
                Drawable icon = mutateOnMainThread(mManager.loadIcon(info, mIconCache));
                if (icon != null) {
                    ...
                    icon.draw(c);
                }
            } catch (Resources.NotFoundException e) { }
            c.setBitmap(null);
        }
        int imageHeight = Math.min(preview.getHeight(), previewHeight + mProfileBadgeMargin);
        return mManager.getBadgeBitmap(info, preview, imageHeight);
    }複製程式碼

整個過程就是從系統載入出Widget對應的Drawable然後繪製到Bitmap上面返回,然後在onPostExecute方法中將該圖片新增到WidgetCell上面,就顯示到了WidgetCell列表中。整個載入就完成了。

Widget的新增:

我們之前講過,Widget列表最後是繫結到WidgetsContainerView中的,而我們將Widget放置到桌面是通過長按拖拽到桌面來完成的,因此我們可以知道新增的觸發事件是通過長按事件來觸發的,因為我們找到WidgetsContainerView中的長按事件:

    @Override
    public boolean onLongClick(View v) {

        ...

        boolean status = beginDragging(v);
        if (status && v.getTag() instanceof PendingAddWidgetInfo) {
            WidgetHostViewLoader hostLoader = new WidgetHostViewLoader(mLauncher, v);
            boolean preloadStatus = hostLoader.preloadWidget();
            ...
            mLauncher.getDragController().addDragListener(hostLoader);
        }
        return status;
    }複製程式碼

首先呼叫beginDragging方法:

    private boolean beginDragging(View v) {
        if (v instanceof WidgetCell) {
            if (!beginDraggingWidget((WidgetCell) v)) {
                return false;
            }
        } else {
            Log.e(TAG, "Unexpected dragging view: " + v);
        }

        // We don't enter spring-loaded mode if the drag has been cancelled
        if (mLauncher.getDragController().isDragging()) {
            // Go into spring loaded mode (must happen before we startDrag())
            mLauncher.enterSpringLoadedDragMode();
        }

        return true;
    }複製程式碼

如果是Widget的檢視(WidgetCell)也就是長按的是Widget佈局則呼叫beginDraggingWidget方法:

private boolean beginDraggingWidget(WidgetCell v) {
        WidgetImageView image = (WidgetImageView) v.findViewById(R.id.widget_preview);
        ...

        if (createItemInfo instanceof PendingAddWidgetInfo) {
            ...
            Bitmap icon = image.getBitmap();
            float minScale = 1.25f;
            int maxWidth = Math.min((int) (icon.getWidth() * minScale), size[0]);

            ...
            preview = getWidgetPreviewLoader().generateWidgetPreview(mLauncher,
                    createWidgetInfo.info, maxWidth, null, previewSizeBeforeScale);

            ...
            scale = bounds.width() / (float) preview.getWidth();
        } else {
            // shortcut
            ...
        }

        // Don't clip alpha values for the drag outline if we're using the default widget preview
        boolean clipAlpha = !(createItemInfo instanceof PendingAddWidgetInfo &&
                (((PendingAddWidgetInfo) createItemInfo).previewImage == 0));

        // Start the drag
        mLauncher.lockScreenOrientation();
        mLauncher.getWorkspace().onDragStartedWithItem(createItemInfo, preview, clipAlpha);
        mDragController.startDrag(image, preview, this, createItemInfo,
                bounds, DragController.DRAG_ACTION_COPY, scale);

        preview.recycle();
        return true;
    }複製程式碼

上面程式碼中的generateWidgetPreview方法我們在上面已經講過了,就是生產WidgetCell圖片的,然後鎖定螢幕旋轉,然後呼叫onDragStartedWithItem方法:

    public void onDragStartedWithItem(PendingAddItemInfo info, Bitmap b, boolean clipAlpha) {
        int[] size = estimateItemSize(info, false);

        // The outline is used to visualize where the item will land if dropped
        mDragOutline = createDragOutline(b, DRAG_BITMAP_PADDING, size[0], size[1], clipAlpha);
    }複製程式碼

整個方法在拖拽中講過,就是在workspace中生成一個拖拽view的輪廓邊框,然後呼叫mDragController.startDrag方法,之後的過程在拖拽章節中有很詳細的講解,所以在此不再重複了,沒看過拖拽的可以去看拖拽過程詳解。下面只是個提示過程。

在放置到桌面時會呼叫onDrop方法,然後呼叫onDropExternal方法,然後呼叫addPendingItem方法:

public void addPendingItem(PendingAddItemInfo info, long container, long screenId,
                               int[] cell, int spanX, int spanY) {
        switch (info.itemType) {
            case LauncherSettings.Favorites.ITEM_TYPE_CUSTOM_APPWIDGET:
            case LauncherSettings.Favorites.ITEM_TYPE_APPWIDGET:
                int span[] = new int[2];
                span[0] = spanX;
                span[1] = spanY;
                addAppWidgetFromDrop((PendingAddWidgetInfo) info,
                        container, screenId, cell, span);
                break;
            ...
            }
    }複製程式碼

如果是Widget則呼叫addAppWidgetFromDrop方法,然後呼叫addAppWidgetImpl方法,然後呼叫completeAddAppWidget方法,最後呼叫mWorkspace.addInScreen方法就講WidgetCell新增到了桌面上。

Widget的大小調節:

我們在桌面上新增完Widget後,如果長按你會發現在Widget四個邊緣會出現拖動框,如果拖動可以調節小外掛的大小,那麼這個拖動框在哪裡新增的呢,我們看一下,其實這個方法是DragLayer中的addResizeFrame方法,這個方法是在Workspace中的onDrop方法中呼叫的,也就是放到桌面上的時候就新增了。

我們看一下這個方法:

public void addResizeFrame(ItemInfo itemInfo, LauncherAppWidgetHostView widget,
            CellLayout cellLayout) {
        AppWidgetResizeFrame resizeFrame = new AppWidgetResizeFrame(getContext(),
                widget, cellLayout, this);

        LayoutParams lp = new LayoutParams(-1, -1);
        lp.customPosition = true;

        addView(resizeFrame, lp);
        mResizeFrames.add(resizeFrame);

        resizeFrame.snapToWidget(false);
    }複製程式碼

首先建立AppWidgetResizeFrame物件,傳入引數LauncherAppWidgetHostView、CellLayout,還有draglayer:

    public AppWidgetResizeFrame(Context context,
            LauncherAppWidgetHostView widgetView, CellLayout cellLayout, DragLayer dragLayer) {

        //初始化資料
        ...

        // 初始化左側拖動點
        mLeftHandle = new ImageView(context);
        mLeftHandle.setImageResource(R.drawable.ic_widget_resize_handle);
        lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT,
                Gravity.LEFT | Gravity.CENTER_VERTICAL);
        lp.leftMargin = handleMargin;
        addView(mLeftHandle, lp);

        // 初始化右側拖動點
        // 初始化頂部拖動點
        // 初始化底部拖動點

        ...
    }複製程式碼

拖動調整大小是在DragLayer中的onTouchEvent方法中:

    @Override
    public boolean onTouchEvent(MotionEvent ev) {

        ...

        if (mCurrentResizeFrame != null) {
            handled = true;
            switch (action) {
                case MotionEvent.ACTION_MOVE:
                    mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
                    break;
                case MotionEvent.ACTION_CANCEL:
                case MotionEvent.ACTION_UP:
                    mCurrentResizeFrame.visualizeResizeForDelta(x - mXDown, y - mYDown);
                    mCurrentResizeFrame.onTouchUp();
                    mCurrentResizeFrame = null;
            }
        }
        if (handled) return true;
        return mDragController.onTouchEvent(ev);
    }複製程式碼

由上面程式碼可以看出拖拽的的時候呼叫visualizeResizeForDelta方法,手指抬起的時候呼叫visualizeResizeForDelta方法和onTouchUp方法,我們先看visualizeResizeForDelta方法:

  private void visualizeResizeForDelta(int deltaX, int deltaY, boolean onDismiss) {
        updateDeltas(deltaX, deltaY);
        DragLayer.LayoutParams lp = (DragLayer.LayoutParams) getLayoutParams();

        if (mLeftBorderActive) {
            lp.x = mBaselineX + mDeltaX;
            lp.width = mBaselineWidth - mDeltaX;
        } else if (mRightBorderActive) {
            lp.width = mBaselineWidth + mDeltaX;
        }

        if (mTopBorderActive) {
            lp.y = mBaselineY + mDeltaY;
            lp.height = mBaselineHeight - mDeltaY;
        } else if (mBottomBorderActive) {
            lp.height = mBaselineHeight + mDeltaY;
        }

        resizeWidgetIfNeeded(onDismiss);
        requestLayout();
    }複製程式碼

首先呼叫updateDeltas方法:

    public void updateDeltas(int deltaX, int deltaY) {
        if (mLeftBorderActive) {
            mDeltaX = Math.max(-mBaselineX, deltaX); 
            mDeltaX = Math.min(mBaselineWidth - 2 * mTouchTargetWidth, mDeltaX);
        } else if (mRightBorderActive) {
            mDeltaX = Math.min(mDragLayer.getWidth() - (mBaselineX + mBaselineWidth), deltaX);
            mDeltaX = Math.max(-mBaselineWidth + 2 * mTouchTargetWidth, mDeltaX);
        }

        if (mTopBorderActive) {
            mDeltaY = Math.max(-mBaselineY, deltaY);
            mDeltaY = Math.min(mBaselineHeight - 2 * mTouchTargetWidth, mDeltaY);
        } else if (mBottomBorderActive) {
            mDeltaY = Math.min(mDragLayer.getHeight() - (mBaselineY + mBaselineHeight), deltaY);
            mDeltaY = Math.max(-mBaselineHeight + 2 * mTouchTargetWidth, mDeltaY);
        }
    }複製程式碼

主要是根據上下左右點來計算mDeltaX和mDeltaY的值,然後設定DragLayer.LayoutParams的值,然後呼叫resizeWidgetIfNeeded方法:

private void resizeWidgetIfNeeded(boolean onDismiss) {
        ...

        if (mLeftBorderActive) {
            cellXInc = Math.max(-cellX, hSpanInc);
            cellXInc = Math.min(lp.cellHSpan - mMinHSpan, cellXInc);
            hSpanInc *= -1;
            hSpanInc = Math.min(cellX, hSpanInc);
            hSpanInc = Math.max(-(lp.cellHSpan - mMinHSpan), hSpanInc);
            hSpanDelta = -hSpanInc;

        }

        ...

        // Update the widget's dimensions and position according to the deltas computed above
        if (mLeftBorderActive || mRightBorderActive) {
            spanX += hSpanInc;
            cellX += cellXInc;
            if (hSpanDelta != 0) {
                mDirectionVector[0] = mLeftBorderActive ? -1 : 1;
            }
        }

        ...

        if (mCellLayout.createAreaForResize(cellX, cellY, spanX, spanY, mWidgetView,
                mDirectionVector, onDismiss)) {
            lp.tmpCellX = cellX;
            lp.tmpCellY = cellY;
            lp.cellHSpan = spanX;
            lp.cellVSpan = spanY;
            mRunningVInc += vSpanDelta;
            mRunningHInc += hSpanDelta;
            if (!onDismiss) {
                updateWidgetSizeRanges(mWidgetView, mLauncher, spanX, spanY);
            }
        }
        mWidgetView.requestLayout();
    }複製程式碼

這裡計算拖拽過程中的引數,然後呼叫updateWidgetSizeRanges方法:

    static void updateWidgetSizeRanges(AppWidgetHostView widgetView, Launcher launcher,
            int spanX, int spanY) {
        getWidgetSizeRanges(launcher, spanX, spanY, sTmpRect);
        widgetView.updateAppWidgetSize(null, sTmpRect.left, sTmpRect.top,
                sTmpRect.right, sTmpRect.bottom);
    }複製程式碼

首先呼叫getWidgetSizeRanges方法來設定sTmpRect引數,然後呼叫widgetView.updateAppWidgetSize方法更新widget大小,然後呼叫mWidgetView.requestLayout方法重新整理widget。

我們再看onTouchUp方法:

    public void onTouchUp() {
        int xThreshold = mCellLayout.getCellWidth() + mCellLayout.getWidthGap();
        int yThreshold = mCellLayout.getCellHeight() + mCellLayout.getHeightGap();

        ...

        post(new Runnable() {
            @Override
            public void run() {
                snapToWidget(true);
            }
        });
    }複製程式碼

這個方法是調整完widget大小手指離開螢幕時呼叫的,主要呼叫了snapToWidget方法,這個方法程式碼就不貼了,主要是四個點的動畫,程式碼很簡單。

到此widget的載入、新增以及大小調整就介紹完了,整個過程也是比較複雜的,所以還是要好好熟悉一下。

最後

同步釋出:www.codemx.cn/2016/12/18/…

Github地址:github.com/yuchuangu85…

微信公眾賬號:Code-MX

墨香帶你學Launcher之(七)--小部件的載入、新增以及大小調節

注:本文原創,轉載請註明出處,多謝。

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