自定義控件_側滑刪除實現

用法:

<com.example.administrator.myapplication.GestureDemoView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:orientation="horizontal"
        android:layout_height="80dp">

        // 該佈局內寫條目業務邏輯
        <LinearLayout
            android:gravity="center"
            android:layout_width="match_parent"
            android:layout_height="80dp"
            />
        // 該佈局內寫條目側滑業務邏輯
        <LinearLayout
            android:gravity="center"
            android:layout_width="100dp"
            android:layout_height="match_parent"
            android:background="#666999"/>


    </com.example.administrator.myapplication.GestureDemoView>

/**
 * Created by Administrator on 2020/2/24.
 */

public class GestureDemoView extends LinearLayout {
    private GestureDetector gestureDetector;
    private  Scroller scroller;

    /**        Explain : 側滑模塊的寬度
    * @author LiXiang create at 2020/2/24 21:51*/
    private int MAX_SCROLL_EXTENT;

    public GestureDemoView2(Context context) {
        super(context);
    }

    public GestureDemoView2(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs,0);
    }

    public GestureDemoView2(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public GestureDemoView2(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        scroller = new Scroller(context, new LinearInterpolator());
        gestureDetector = new GestureDetector(context,simpleOnGestureListener);
    }

    GestureDetector.SimpleOnGestureListener simpleOnGestureListener = new GestureDetector.SimpleOnGestureListener(){

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            int  scaleX = getScrollX();

            /**        Explain : 獲取當前剩下的右側滑動距離
            * @author LiXiang create at 2020/2/24 21:51*/
            int  surplusRightScrolldistance = MAX_SCROLL_EXTENT - scaleX;

            /**        Explain : 獲取當前剩下的左側滑動距離
             * @author LiXiang create at 2020/2/24 21:51*/
            int  surplusLeftScrolldistance = - scaleX;

            /**        Explain : 設定右側閾值:當滑動距離大於剩餘部分時,就設定爲當前剩餘值
            * @author LiXiang create at 2020/2/24 21:55*/
            if (distanceX > surplusRightScrolldistance) {
                distanceX = surplusRightScrolldistance;
            }else  if (distanceX < surplusLeftScrolldistance){
                /**        Explain : 設定左側閾值:當滑動距離小於負剩餘部分時,就設定爲當前剩餘值
                 * @author LiXiang create at 2020/2/24 21:55*/
                distanceX = surplusLeftScrolldistance;
            }
            scrollBy((int)distanceX,0);
            return true;
        }


        /**        Explain : 往左拋往左滑動,往右拋往右滑動
        * @author LiXiang create at 2020/2/24 21:56*/
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if (velocityX < 0){
                rightScroll();
            }else {
                leftScroll();
            }
            return true;
        }
    };

    private void leftScroll() {
        scroller.startScroll(getScrollX(),0,-getScrollX(),0);
        invalidate();
    }

    private void rightScroll() {
        scroller.startScroll(getScrollX(),0,MAX_SCROLL_EXTENT-getScrollX(),0);
        invalidate();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        /**        Explain : 監聽擡起動作,以最大寬度的一半爲閾值點
        * @author LiXiang create at 2020/2/24 21:57*/
        gestureDetector.onTouchEvent(event);
        if (event.getAction() == MotionEvent.ACTION_UP) {
            if (getScrollX()>MAX_SCROLL_EXTENT/2) {
                rightScroll();
            }else {
                leftScroll();
            }
            return true;
        }
        return super.onTouchEvent(event);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            View childAt = getChildAt(i);
            measureChild(childAt,widthMeasureSpec, heightMeasureSpec);
            if (i==1) {
                /**        Explain : 側滑模塊的寬度
                * @author LiXiang create at 2020/2/24 21:57*/
                MAX_SCROLL_EXTENT = childAt.getMeasuredWidth();
            }
        }

    }


    /**        Explain : 實現剩餘部分的自動滑動
    * @author LiXiang create at 2020/2/24 21:58*/
    @Override
    public void computeScroll() {
        super.computeScroll();
        if (scroller.computeScrollOffset()) {
            scrollTo(scroller.getCurrX(),scroller.getCurrY());
            postInvalidate();
        }
    }
}

Interpolator插值器