Android 监听软键盘弹起消失的布局

SoftListenLayout.java

import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.WindowManager;
import android.widget.RelativeLayout;
import java.util.ArrayList;

public class SoftListenLayout extends RelativeLayout {

  private OnKeyboardChangedListener onKeyboardChangedListener;
  private int mMaxParentHeight = 0;
  private ArrayList<Integer> heightList = new ArrayList<>();
  private int mOldHeight = 0;
  private int mMinLayoutHeight = 0;
  private int mMaxNavBarHeight = 0;

  public SoftListenLayout(Context context, AttributeSet attrs) {
    super(context, attrs);
    WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    DisplayMetrics metrics = new DisplayMetrics();
    manager.getDefaultDisplay().getMetrics(metrics);
    mMinLayoutHeight =
        metrics.heightPixels * 2 / 3; //the height of layout is at least 2/3 of screen height
    mMaxNavBarHeight = metrics.heightPixels / 6; // max height of navigation bar is 1/6 of height
  }

  /**
   * when keyboard hide, three onMeasure will be called
   * onMeasure measureHeight = 1533
   * onMeasure measureHeight = 725
   * onLayout top = 0, bottom = 1533
   * onMeasure measureHeight = 725
   * onLayout top = 0, bottom = 725
   */
  @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int measureHeight = measureHeight(heightMeasureSpec);

    if (mMaxParentHeight != 0
        && Math.abs(measureHeight - mOldHeight)
        < mMaxNavBarHeight) {  //for some devices whose the bottom navigation bar can be hiden or shown
      mMaxParentHeight += (measureHeight - mOldHeight);
    } else if (mMaxParentHeight == 0
        || measureHeight > mMinLayoutHeight) {  //ignore keyboard shown making height shorter
      mMaxParentHeight = measureHeight;
    }

    heightList.add(measureHeight);

    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int expandSpec = MeasureSpec.makeMeasureSpec(mMaxParentHeight, heightMode);
    super.onMeasure(widthMeasureSpec, expandSpec);

    mOldHeight = measureHeight;
  }

  @Override protected void onLayout(boolean changed, int l, int t, int r, int b) {
    super.onLayout(changed, l, t, r, mMaxParentHeight);
    if (heightList.size() >= 2) {     //keyboard hide or show, onMeasure will be called twice
      int oldh = heightList.get(0);
      int newh = heightList.get(heightList.size() - 1);

      int dividerHeight = Math.abs(newh - oldh);
      if (dividerHeight > mMaxNavBarHeight) { //means keyboard hide or show
        if (newh < oldh) {
          if (null != onKeyboardChangedListener) {
            onKeyboardChangedListener.onSoftKeyboardPop(dividerHeight);
          }
        } else {
          if (null != onKeyboardChangedListener) {
            onKeyboardChangedListener.
                onSoftKeyboardClose();
          }
        }
      }

      heightList.clear();
    } else {
      heightList.clear();
    }
  }

  private int measureHeight(int pHeightMeasureSpec) {
    int result = 0;
    int heightMode = MeasureSpec.getMode(pHeightMeasureSpec);
    int heightSize = MeasureSpec.getSize(pHeightMeasureSpec);

    switch (heightMode) {
      case MeasureSpec.AT_MOST:
      case MeasureSpec.EXACTLY:
        result = heightSize;
        break;
    }
    return result;
  }

  public void setOnKeyboardChangedListener(OnKeyboardChangedListener onKeyboardChangedListener) {
    this.onKeyboardChangedListener = onKeyboardChangedListener;
  }

  public interface OnKeyboardChangedListener {
    void onSoftKeyboardPop(int height);

    void onSoftKeyboardClose();
  }
}