Android获取软键盘高度

本文获取软键盘高度利用View里getWindowVisibleDisplayFrame (Rect outRect)方法，根据当软键盘弹出时所影响的outRect底部值bottom的偏差值来判断，现以为使bottom产生变化的有软键盘，虚拟导航键2种，所以区分此2种变化即可获取软键盘的高度，这里用了一个估计值，就是大于屏幕高度的1/4就以为是软键盘高度。取1/4这个比例主要还是考虑兼容全面屏，具体代码如下：

/**
 * 软键盘高度监听者，思路:当底部坐标变化超过整个屏幕的1/4即认为是这个偏差为软键盘高度
 */
public class KeyLayoutListener implements ViewTreeObserver.OnGlobalLayoutListener {
    @NonNull
    private Activity mActivity;
    private int mScreenHeight;
    private Rect mOutRect = new Rect();
    private int mWindowVisibleDisplayFrameBottom;
    private OnGetKeyHeightListener onGetKeyHeightListener;

    public KeyLayoutListener(@NonNull Activity activity) {
        mActivity = activity;
        mScreenHeight = getScreenHeight();
    }

    @Override
    public void onGlobalLayout() {
        Window window = mActivity.getWindow();
        if (window == null)
            return;
        mOutRect.setEmpty();
        window.getDecorView().getWindowVisibleDisplayFrame(mOutRect);
        int offset = mWindowVisibleDisplayFrameBottom - mOutRect.bottom;
        if (offset > mScreenHeight / 4) {
            if (onGetKeyHeightListener != null) {
                onGetKeyHeightListener.onGet(offset);
            }
        } else {
            mWindowVisibleDisplayFrameBottom = mOutRect.bottom;
        }
    }

    private int getScreenHeight() {
        WindowManager wm = (WindowManager) mActivity.getSystemService(Context.WINDOW_SERVICE);
        if (wm == null) {
            return mActivity.getResources().getDisplayMetrics().heightPixels;
        }
        Point point = new Point();
        if (Build.VERSION.SDK_INT >= 17) {
            wm.getDefaultDisplay().getRealSize(point);
        } else {
            wm.getDefaultDisplay().getSize(point);
        }
        return point.y;
    }

    public void setOnGetKeyHeightListener(OnGetKeyHeightListener onGetKeyHeightListener) {
        this.onGetKeyHeightListener = onGetKeyHeightListener;
    }

    public interface OnGetKeyHeightListener {
        void onGet(int keyBoardHeight);
    }
}

测试Activity的代码如下：

public class KeyboardActivity extends AppCompatActivity implements View.OnClickListener {

    private KeyLayoutListener mKeyLayoutListener;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_keyboard);
        Button button = findViewById(R.id.button);
        button.setOnClickListener(this);
        mKeyLayoutListener = new KeyLayoutListener(this);
        mKeyLayoutListener.setOnGetKeyHeightListener(new KeyLayoutListener.OnGetKeyHeightListener() {
            @Override
            public void onGet(int keyBoardHeight) {
                Log.i("KeyboardActivity", "keyBoardHeight:" + keyBoardHeight);
            }
        });
        getWindow().getDecorView().getViewTreeObserver().addOnGlobalLayoutListener(mKeyLayoutListener);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mKeyLayoutListener != null) {
            getWindow().getDecorView().getViewTreeObserver().removeOnGlobalLayoutListener(mKeyLayoutListener);
        }
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.button) {
            Log.i("KeyboardActivity", "isSoftShowing:" + isSoftShowing());
        }
    }

    private boolean isSoftShowing() {
        //获取当前屏幕内容的高度
        int screenHeight = getWindow().getDecorView().getHeight();
        //获取View可见区域的bottom
        Rect rect = new Rect();
        //DecorView即为activity的*view
        getWindow().getDecorView().getWindowVisibleDisplayFrame(rect);
        //考虑到虚拟导航栏的情况（虚拟导航栏情况下：screenHeight = rect.bottom + 虚拟导航栏高度）
        //选取screenHeight*3/4进行判断
        return screenHeight * 3 / 4 > rect.bottom;
    }

}

最后再附上activity_keyboard.xml的代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="获取状态" />

</LinearLayout>