仿折800，拖拽控件悬停在左边右边 用的是 ViewDragHelper

之前想做一个类似刷新的控件，拖动悬停的，大部分app都有这个功能了，之前做的思路是：onTouchEvent 里面拿到xy，onlayout 给位置，这样做也不错,不过不是自带的，而且在抬起的事件里面也是判断的坐标，来给的位置，是没有动画的。看起来不是很友好。

直接放源码不难的：如果你对它不熟可以看

http://blog.csdn.net/lmj623565791/article/details/46858663

package com.example.wuyakun.myapplication1.view;import android.content.Context;import android.support.v4.widget.ViewDragHelper;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.widget.LinearLayout;/** * Created by WYK on 16/8/15. */public class VDHLayout extends LinearLayout {    private ViewDragHelper mViewDragHelper;    public VDHLayout(Context context) {        super(context);        throw new RuntimeException("you can not do this.");    }    public VDHLayout(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public VDHLayout(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        mViewDragHelper = ViewDragHelper.create(this, 1.0f, new ViewDragHelper.Callback() {            @Override            public boolean tryCaptureView(View child, int pointerId) {                //是否可以拖拽                return true;            }            @Override            public int clampViewPositionHorizontal(View child, int left, int dx) {                //不允许超过  控件左边到  最左边-paddingLeft的距离                final int leftBound = getPaddingLeft();                final int rightBound = getWidth() - child.getWidth() - getPaddingRight();                return Math.min(Math.max(left, leftBound), rightBound);            }            @Override            public int clampViewPositionVertical(View child, int top, int dy) {                //同理                final int topBound = getPaddingTop();                final int bottomBound = getHeight() - child.getHeight() - getPaddingBottom();                return Math.min(Math.max(top, topBound), bottomBound);            }            //手指释放的时候回调            @Override            public void onViewReleased(View releasedChild, float xvel, float yvel) {                int x = releasedChild.getLeft();                int y = releasedChild.getTop();                int paddingLeft = getPaddingLeft();                int paddingRight = getPaddingRight();                if (x > (getWidth() - releasedChild.getWidth()) / 2 - paddingLeft) {                    //如果在右边一半                    x = getWidth() - paddingRight - releasedChild.getWidth();                } else {                    //否则就在左边                    x = paddingLeft;                }                //控制它动画返回到哪里                mViewDragHelper.settleCapturedViewAt(x, y);                invalidate();            }            /**             * 大于 0 才可以拖动             * 因为设置了android:clickable="true"             * 也就是点击事件,需要在下面方法里面返回大于 0 要不然不能拖了             * @param child             * @return             */            @Override            public int getViewHorizontalDragRange(View child) {                return getMeasuredWidth() - child.getMeasuredWidth();            }            @Override            public int getViewVerticalDragRange(View child) {                return getMeasuredHeight() - child.getMeasuredHeight();            }        });    }    /**     * Touch 交给 ViewDragHelper     *     * @param event     * @return     */    @Override    public boolean onTouchEvent(MotionEvent event) {        mViewDragHelper.processTouchEvent(event);        return true;    }    /**     * 拦截 交给 ViewDragHelper     *     * @param ev     * @return     */    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        return mViewDragHelper.shouldInterceptTouchEvent(ev);    }    /**     * 为滚动而生 -- 主要是为了 settleCapturedViewAt     * 想知道为啥可以看下上面的链接里的文章     */    @Override    public void computeScroll() {        if (mViewDragHelper.continueSettling(true)) {            invalidate();        }    }    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);    }    @Override    protected void onFinishInflate() {        super.onFinishInflate();    }}

layout 也很简单：

<?xml version="1.0" encoding="utf-8"?><com.example.wuyakun.myapplication1.view.VDHLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:paddingBottom="@dimen/fab_margin"    android:paddingLeft="@dimen/fab_margin"    >    <LinearLayout        android:id="@+id/lyt_test"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:clickable="true"        android:orientation="vertical"        >        <TextView            android:id="@+id/textView"            android:layout_width="100dp"            android:layout_height="100dp"            android:background="#7ccccccc"            android:gravity="center"            android:text="New Text"/>    </LinearLayout></com.example.wuyakun.myapplication1.view.VDHLayout>

activity 也贴一下

package com.example.wuyakun.myapplication1;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.Toast;/** * Created by WYK on 16/8/16. */public class TestActivity extends AppCompatActivity {    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.test_layout);        findViewById(R.id.lyt_test).setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                Toast.makeText(TestActivity.this, "test", Toast.LENGTH_SHORT).show();            }        });    }}

可能有计算啥的错了一点点，需要你去学会了，直接改

动态图我就不贴了，防止你偷懒