ViewTreeObserver.OnGlobalLayoutListener layoutListener =
        new ViewTreeObserver.OnGlobalLayoutListener() {
      int mScreenHeight = 0;
      int mKeyboardHeight = 0;
      @Override
      public void onGlobalLayout() {
        Rect rect = new Rect();
        // 测量当前窗口的显示区域
        ((Activity)getContext()).getWindow().getDecorView()
            .getWindowVisibleDisplayFrame(rect);
        if(mScreenHeight <= 0){
          mScreenHeight = ((WindowManager) getContext()
              .getSystemService(Context.WINDOW_SERVICE))
              .getDefaultDisplay().getHeight();
        }
        //计算出软键盘的高度
        int keyboardHeight = mScreenHeight - rect.bottom;

        //如果keyboardHeight大于屏幕的五分之一，
        // 此时keyboardHeight有效，反之就是软键盘已经关闭了。
        if (Math.abs(keyboardHeight) > mScreenHeight / 5) {
          mKeyboardHeight = keyboardHeight;
        }
      }
    }

<activity android:name=".activity.xxx"
Android:windowSoftInputMode="stateVisible|adjustResize"/>

<style name="NoTitleDialogTheme" parent="android:style/Theme.Dialog">
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowCloseOnTouchOutside">false</item>
  </style>

<activity android:name=".FloatEditorActivity"
      android:windowSoftInputMode="stateAlwaysVisible"
      android:theme="@style/NoTitleDialogTheme"/>

public class FloatEditorActivity extends Activity implements View.OnClickListener {
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.id.editorlayout);
    getWindow().setLayout(ViewGroup.LayoutParams.MATCH_PARENT,
     ViewGroup.LayoutParams.WRAP_CONTENT);
    getWindow().setGravity(Gravity.BOTTOM);
  }
}