public class MainActivity extends Activity {
  //添加数据按钮
  private ImageView addDataIv;
  //下拉功能菜单
  private LinearLayout dropDownView;
  private View bgView;
  //当前下拉菜单是否为显示状态
  private boolean showItems = false;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    addDataIv = (ImageView) findViewById(R.id.main_newData);
    dropDownView = (LinearLayout) findViewById(R.id.dropDownView);
    bgView = findViewById(R.id.main_bg);
    addDataIv.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        if (!showItems) {
          showView();
        } else {
          dismissView();
        }
      }
    });
    //点击空白隐藏弹出框
    bgView.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        if (showItems) {
          dismissView();
        }
      }
    });
    //下拉功能菜单上按钮的点击事件
    View.OnClickListener l = new OnClickImpl();
    findViewById(R.id.dropDown_item1).setOnClickListener(l);
    findViewById(R.id.dropDown_item2).setOnClickListener(l);
    findViewById(R.id.dropDown_item3).setOnClickListener(l);
    findViewById(R.id.dropDown_item4).setOnClickListener(l);
  }
  //显示下拉菜单
  private void showView() {
    showItems = true;
    addDataIv.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, R.anim.rotate_open));
    dropDownView.startAnimation(AnimationUtils.loadAnimation(this, R.anim.drop_down));
    dropDownView.setVisibility(View.VISIBLE);
    bgView.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, R.anim.fade_dark));
    bgView.setVisibility(View.VISIBLE);
  }
  //隐藏下拉菜单
  private void dismissView() {
    showItems = false;
    addDataIv.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, R.anim.rotate_close));
    Animation dropUpAnim = AnimationUtils.loadAnimation(this, R.anim.drop_up);
    dropUpAnim.setAnimationListener(new AnimListenerImpl(dropDownView));
    dropDownView.startAnimation(dropUpAnim);
    dropDownView.setVisibility(View.INVISIBLE);
    Animation fadeLightAnim = AnimationUtils.loadAnimation(MainActivity.this, R.anim.fade_light);
    fadeLightAnim.setAnimationListener(new AnimListenerImpl(bgView));
    bgView.startAnimation(fadeLightAnim);
    bgView.setVisibility(View.INVISIBLE);
  }
  //点击返回键时，如果下拉菜单是显示状态，则隐藏它
  @Override
  public void onBackPressed() {
    if (showItems) {
      dismissView();
      return;
    }
    super.onBackPressed();
  }
  private class OnClickImpl implements View.OnClickListener {
    @Override
    public void onClick(View v) {
      if (!showItems) {
        return;
      }
      int id = v.getId();
      switch (id) {
        case R.id.dropDown_item1:
          Toast.makeText(MainActivity.this, "item1 onClick", Toast.LENGTH_SHORT).show();
          dismissView();
          break;
        case R.id.dropDown_item2:
          Toast.makeText(MainActivity.this, "item2 onClick", Toast.LENGTH_SHORT).show();
          dismissView();
          break;
        case R.id.dropDown_item3:
          Toast.makeText(MainActivity.this, "item3 onClick", Toast.LENGTH_SHORT).show();
          dismissView();
          break;
        case R.id.dropDown_item4:
          Toast.makeText(MainActivity.this, "item4 onClick", Toast.LENGTH_SHORT).show();
          dismissView();
          break;
        default:
          break;
      }
    }
  }
  //动画结束后必须clearAnimation，否则隐藏状态的view依然能响应点击事件
  private class AnimListenerImpl implements Animation.AnimationListener {
    private View view;
    public AnimListenerImpl(View view) {
      this.view = view;
    }
    @Override
    public void onAnimationStart(Animation animation) {
    }
    @Override
    public void onAnimationEnd(Animation animation) {
      view.clearAnimation();
    }
    @Override
    public void onAnimationRepeat(Animation animation) {
    }
  }
}