Android ListView弹性效果，处理空ListView， 监听事件

1. ListView用于展示数据列表，没有数据是我们可以设置setEmptyView（)设置默认显示

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <com.example.administrator.testdemo.view.TopBar
        android:id="@+id/top_bar"
        android:layout_width="match_parent"
        android:layout_height="50dip"
        android:layout_alignParentTop="true"
        app:title="标题"
        ></com.example.administrator.testdemo.view.TopBar>
    <!--<include layout="@layout/tap_bar_layout"></include>-->
    <com.example.administrator.testdemo.view.MyListView
        android:id="@+id/my_list"
        android:layout_below="@+id/top_bar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></com.example.administrator.testdemo.view.MyListView>
    <ImageView
        android:id="@+id/empty_image"
        android:layout_below="@+id/my_list"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"
        android:visibility="gone"
        />
</RelativeLayout>

my_list.setEmptyView(findViewById(R.id.empty_image));

当ListView有数据是图片不显示，没有数据时图片显示。

2.ListView的监听事件

setOnTouchListener

       my_list.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent) {
                switch (motionEvent.getAction()){
                    case MotionEvent.ACTION_DOWN:
                        //触摸时操作
                        break;
                    case MotionEvent.ACTION_MOVE:
                        //移动时操作
                        break;
                    case MotionEvent.ACTION_UP:
                        //离开时操作
                        break;
                }
                return false;
            }
        });

setOnScrollListener

       my_list.setOnScrollListener(new AbsListView.OnScrollListener() {
           @Override
           public void onScrollStateChanged(AbsListView absListView, int i) {
               switch (i){
                   //判断滑动状态，做出处理
               }
           }

           @Override
           public void onScroll(AbsListView absListView, int i, int i1, int i2) {

           }
       });

ListView 滑动弹性设置 重写overScrollBy

public class MyListView extends ListView {
    private int mMaxOverDistance ;
    private Context mcontent ;
    private static final int MAX_Y_DISTANCE = 100;
    public MyListView(Context context) {
        super(context);
        mcontent =context ;
        initView() ;
    }

    public MyListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mcontent = context ;
        initView();
    }

    public MyListView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX, int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {
        initView();
        return super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX, scrollRangeY, maxOverScrollX, mMaxOverDistance, isTouchEvent);
    }

    private void initView(){
        DisplayMetrics metrics = mcontent.getResources().getDisplayMetrics() ;
        float density = metrics.density ;
        mMaxOverDistance =(int) (density*MAX_Y_DISTANCE);
    }

}