AndroidStickListView实现悬停效果

public class CustomViewAcyivity extends BaseActivity {

  Toolbar toolbar;
  WindowManager mWindowManager;
  WindowManager.LayoutParams mWindowLayoutParams;
  TextView mTv;
  boolean isShowing;//是否正在显示

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_custom_view);

    mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

    List list = new ArrayList<>();
    for (int i = 0; i <30; i++) {
      list.add("我是第" + (i + 1) + "个选择项");
    }

    toolbar = $(R.id.toolbar);
    ListView listView = $(R.id.view_list);
    listView.setAdapter(new ArrayAdapter<>(this, R.layout.item_text, list));

    listView.setOnScrollListener(new AbsListView.OnScrollListener() {
      @Override
      public void onScrollStateChanged(AbsListView view, int scrollState) {
      }

      @Override
      public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        if (firstVisibleItem > 8) {//滑动到目的项时，显示悬停布局
          if (!isShowing)
            show();
        } else {
          if (isShowing)
            hide();
        }
      }
    });

  }


  //显示悬停布局
  public void show() {
    isShowing = true;
    mWindowLayoutParams = new WindowManager.LayoutParams();
    mWindowLayoutParams.format = PixelFormat.TRANSLUCENT; //图片之外的其他地方透明
    mWindowLayoutParams.gravity = Gravity.TOP;
    mWindowLayoutParams.y = toolbar.getHeight() - SystemUtil.getStatusHeight(this);//设置悬停布局显示的Y坐标
    mWindowLayoutParams.width = WindowManager.LayoutParams.MATCH_PARENT;
    mWindowLayoutParams.height = UnitUtil.dp2px(this, 50);//设置悬停布局显示的高度
    mWindowLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
        | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;

    //设置悬停布局，为了看起来是悬停效果，布局的内容要设置成与ItemView一致
    mTv = new TextView(this);
    mTv.setGravity(Gravity.CENTER);
    mTv.setBackgroundColor(getResources().getColor(R.color.white));
    mTv.setTextSize(UnitUtil.px2sp(this, UnitUtil.dp2px(this, 16)));
    mTv.setText("我是第10个选择项");

    //添加悬停布局
    mWindowManager.addView(mTv, mWindowLayoutParams);
  }

  //隐藏悬停布局
  public void hide() {
    if (mTv != null) {
      isShowing = false;
      mWindowManager.removeView(mTv);
      mTv = null;
    }
  }

}

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