Android StickListView实现悬停效果

先看看效果图：

实现思路：

监听ListView的滑动，等目的项为列表第一个可见的ItemView时，添加一个一个的布局，产生悬停效果

实现代码：

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<String> 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;
    }
  }
}

布局代码：

<?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">
  <include layout="@layout/view_toolbar" />
  <ListView
    android:id="@+id/view_list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
</LinearLayout>

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