問題與解決
在Android應用的開發中，有一些需求需要我們獲取到輸入法的高度，但是官方的API並沒有提供類似的方法，所以我們需要自己來實現。
查閱了網上很多資料，試過以後都不理想。
比如有的方法通過監聽佈局的變化來計算輸入法的高度，這種方式在Activity的配置中配置為"android:windowSoftInputMode="adjustResize""時沒有問題，可以正確獲取輸入法的高度，因為佈局此時確實會動態的調整。
但是當Activity配置為"android:windowSoftInputMode="adjustNothing""時，佈局不會在輸入法彈出時進行調整，上面的方式就會撲街。
不過經過一番探索和測試，終於發現了一種方式可以在即使設定為adjustNothing時也可以正確計算高度放方法。
同時也感謝這位外國朋友： GitHub地址
其實也就兩個類，我也做了一些修改，解決了一些問題，這裡也貼出來：
- KeyboardHeightObserver.java
/**
* The observer that will be notified when the height of
* the keyboard has changed
*/
public interface KeyboardHeightObserver {
/**
* Called when the keyboard height has changed, 0 means keyboard is closed,
* >= 1 means keyboard is opened.
*
* @param height The height of the keyboard in pixels
* @param orientation The orientation either: Configuration.ORIENTATION_PORTRAIT or
* Configuration.ORIENTATION_LANDSCAPE
*/
void onKeyboardHeightChanged(int height, int orientation);
}
複製程式碼- KeyboardHeightProvider.java
/**
* The keyboard height provider, this class uses a PopupWindow
* to calculate the window height when the floating keyboard is opened and closed.
*/
public class KeyboardHeightProvider extends PopupWindow {
/** The tag for logging purposes */
private final static String TAG = "sample_KeyboardHeightProvider";
/** The keyboard height observer */
private KeyboardHeightObserver observer;
/** The cached landscape height of the keyboard */
private int keyboardLandscapeHeight;
/** The cached portrait height of the keyboard */
private int keyboardPortraitHeight;
/** The view that is used to calculate the keyboard height */
private View popupView;
/** The parent view */
private View parentView;
/** The root activity that uses this KeyboardHeightProvider */
private Activity activity;
/**
* Construct a new KeyboardHeightProvider
*
* @param activity The parent activity
*/
public KeyboardHeightProvider(Activity activity) {
super(activity);
this.activity = activity;
LayoutInflater inflator = (LayoutInflater) activity.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
this.popupView = inflator.inflate(R.layout.keyboard_popup_window, null, false);
setContentView(popupView);
setSoftInputMode(LayoutParams.SOFT_INPUT_ADJUST_RESIZE | LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
setInputMethodMode(PopupWindow.INPUT_METHOD_NEEDED);
parentView = activity.findViewById(android.R.id.content);
setWidth(0);
setHeight(LayoutParams.MATCH_PARENT);
popupView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
if (popupView != null) {
handleOnGlobalLayout();
}
}
});
}
/**
* Start the KeyboardHeightProvider, this must be called after the onResume of the Activity.
* PopupWindows are not allowed to be registered before the onResume has finished
* of the Activity.
*/
public void start() {
if (!isShowing() && parentView.getWindowToken() != null) {
setBackgroundDrawable(new ColorDrawable(0));
showAtLocation(parentView, Gravity.NO_GRAVITY, 0, 0);
}
}
/**
* Close the keyboard height provider,
* this provider will not be used anymore.
*/
public void close() {
this.observer = null;
dismiss();
}
/**
* Set the keyboard height observer to this provider. The
* observer will be notified when the keyboard height has changed.
* For example when the keyboard is opened or closed.
*
* @param observer The observer to be added to this provider.
*/
public void setKeyboardHeightObserver(KeyboardHeightObserver observer) {
this.observer = observer;
}
/**
* Get the screen orientation
*
* @return the screen orientation
*/
private int getScreenOrientation() {
return activity.getResources().getConfiguration().orientation;
}
/**
* Popup window itself is as big as the window of the Activity.
* The keyboard can then be calculated by extracting the popup view bottom
* from the activity window height.
*/
private void handleOnGlobalLayout() {
Point screenSize = new Point();
activity.getWindowManager().getDefaultDisplay().getSize(screenSize);
Rect rect = new Rect();
popupView.getWindowVisibleDisplayFrame(rect);
// REMIND, you may like to change this using the fullscreen size of the phone
// and also using the status bar and navigation bar heights of the phone to calculate
// the keyboard height. But this worked fine on a Nexus.
int orientation = getScreenOrientation();
int keyboardHeight = screenSize.y - rect.bottom;
if (keyboardHeight == 0) {
notifyKeyboardHeightChanged(0, orientation);
}
else if (orientation == Configuration.ORIENTATION_PORTRAIT) {
this.keyboardPortraitHeight = keyboardHeight;
notifyKeyboardHeightChanged(keyboardPortraitHeight, orientation);
}
else {
this.keyboardLandscapeHeight = keyboardHeight;
notifyKeyboardHeightChanged(keyboardLandscapeHeight, orientation);
}
}
private void notifyKeyboardHeightChanged(int height, int orientation) {
if (observer != null) {
observer.onKeyboardHeightChanged(height, orientation);
}
}
}
複製程式碼使用方法
此處以在Activity中的使用進行舉例。
實現介面
引入這兩個類後，在當前Activity中實現介面KeyboardHeightObserver：
@Override
public void onKeyboardHeightChanged(int height, int orientation) {
String or = orientation == Configuration.ORIENTATION_PORTRAIT ? "portrait" : "landscape";
Logger.d(TAG, "onKeyboardHeightChanged in pixels: " + height + " " + or);
}
複製程式碼定義並初始化
在當前Activity定義成員變數，並在onCreate()中進行初始化
private KeyboardHeightProvider mKeyboardHeightProvider;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
...
mKeyboardHeightProvider = new KeyboardHeightProvider(this);
new Handler().post(() -> mKeyboardHeightProvider.start());
}
複製程式碼生命週期處理
初始化完成後，我們要在Activity中的生命週期中也要進行處理，以免記憶體洩露。
@Override
protected void onResume() {
super.onResume();
mKeyboardHeightProvider.setKeyboardHeightObserver(this);
}
@Override
protected void onPause() {
super.onPause();
mKeyboardHeightProvider.setKeyboardHeightObserver(null);
}
@Override
protected void onDestroy() {
super.onDestroy();
mKeyboardHeightProvider.close();
}
複製程式碼總結
此時我們就可以正確獲取的當前輸入法的高度了，即使android:windowSoftInputMode="adjustNothing"時也可以正確獲取到，這正是這個方法的強大之處，利用這個方法可以實現比如類似微信聊天的介面，流暢切換輸入框，表情框等。
如有更多疑問，請參考我的其它Android相關部落格：我的部落格地址