android - 如何检测ListView结束或开始的淡入淡出边缘？

Question

我已经在 StackOverflow 中尝试了很多帖子，但都没有成功。我的要求很简单。我有一个 listView。滚动 listView 时，我想检测 Fading Edge，即当褪色边缘可见时，我想显示 Log massage。如何检测衰落边缘？

*更新:我找到了解决方案。这是我的解决方案。*

第 1 步:首先，我扩展了 ListView，如下所示

ManipulateList.java

public class ManipulateList extends ListView {

public ManipulateList(Context context) {
    super(context);
    // TODO Auto-generated constructor stub
}

public ManipulateList(Context context, AttributeSet attrs) {
    super(context, attrs);
    // TODO Auto-generated constructor stub
}


public ManipulateList(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    // TODO Auto-generated constructor stub
}

@Override
protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX,
        boolean clampedY) {
    // TODO Auto-generated method stub
    Log.d("***", "Over Scrolling: Fading Edge NOW Visible");

    super.onOverScrolled(scrollX, scrollY, clampedX, clampedY);
}


}

在这里您可以看到，我已经覆盖了 onOverScrolled 方法来执行我自己的任务。

第 2 步:“activity_main.xml”声明与我修改后的 ListView

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<com.example.customlist.ManipulateList
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true" >

</com.example.customlist.ManipulateList>

</RelativeLayout>

第 3 步:我的主要 Activity 的 onCreate 方法如下所示

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

    ManipulateList listView = (ManipulateList) findViewById(R.id.listView1);
    String[] swName = new String[] {"a", "b","c",
            "d", "e","f",
            "g", "h","i",
            "j", "k","l",
            "m", "n","o",
            "p", "q","r",
            "s", "t","u",
            "v", "w","x",
            "y","z","a","b",
            "c","d","e","f"
            };


    ArrayAdapter<String> swGAA = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, swName);



    listView.setAdapter(swGAA);




}

第 4 步:尽情享受吧!

Answer 1

“Fading Edge”被称为“Overscroll”效果。

查看onOverScroll()方法。

编辑:它不叫 OverScroll。它叫做EdgeEffect .