上一篇讲到通过通过goolge官方的ViewDragHelper工具实现拖动的方法（上一篇见http://www.jianshu.com/p/94477b804136），那么有一个问题就是在DragframeLayout中的onTouchEvent一直接收不到触摸消息，而且在onInterceptTouchEvent的时候，并没有触发ViewDragHelper.tryCaptureView方法，因此诞生了另一种比较原始的方法：通过自定义可拖动view来实现
主要方法：
initEdge：设置可拖动view能拖动范围的初始边界，一般情况下为父布局的边界。注意view.getLeft…等会获取到会0，我是在网路数据返回的情况下设置边界，并显示的。也有方法开一个子线程获取。

onTouchEvent：拖动的计算以及重新layout

代码：

public class DragImageView extends com.facebook.drawee.view.SimpleDraweeView {
String TAG = "DragImageView";
private Rect mFloatRectArea;//浮层广告的最后拖动位置
private int mSensitive = 5; //拖动灵敏度，影响点击事件，目前测试下来对2K的屏幕正常
public DragImageView(Context context) {
    this(context, null);
}

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

public DragImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}

/**
 * 设置在父布局中的边界
 * @param l
 * @param t
 * @param r
 * @param b
 */
public void initEdge(int l,int t,int r,int b) {
    edgeLeft = l;
    edgeTop = t;
    edgeRight = r;
    edgeBottom = b;
    mFloatRectArea = new Rect(-1,-1,-1,-1);
    Log.e(TAG,"L="+l+";t="+t+";r="+r+";b="+b);
}

int edgeLeft, edgeTop, edgeRight, edgeBottom;
int lastX, lastY, movex, movey, dx, dy;

@Override
public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            lastX = (int) event.getRawX();
            lastY = (int) event.getRawY();
            movex = lastX;
            movey = lastY;
            break;
        case MotionEvent.ACTION_MOVE:
            dx = (int) event.getRawX() - lastX;
            dy = (int) event.getRawY() - lastY;

            int left = getLeft() + dx;
            int top = getTop() + dy;
            int right = getRight() + dx;
            int bottom = getBottom() + dy;
            if (left < edgeLeft) {
                left = edgeLeft;
                right = left + getWidth();
            }
            if (right > edgeRight) {
                right = edgeRight;
                left = right - getWidth();
            }
            if (top < edgeTop) {
                top = edgeTop;
                bottom = top + getHeight();
            }
            if (bottom > edgeBottom) {
                bottom = edgeBottom;
                top = bottom - getHeight();
            }

            layout(left, top, right, bottom);
            lastX = (int) event.getRawX();
            lastY = (int) event.getRawY();
            break;
        case MotionEvent.ACTION_UP:
            //避免滑出触发点击事件
            if ((int) (event.getRawX() - movex) >= mSensitive
                || (int) (event.getRawY() - movey) >= mSensitive) {
                return true;
            }
            break;
        default:
            break;
    }
    return super.onTouchEvent(event);
}
}

布局：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:custom="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/df_content"
android:layout_width="match_parent"
android:layout_height="match_parent">

<com.windfindtech.ishanghai.view.SwipeScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/default_white"
    android:scrollbars="none">

    <RelativeLayout
        android:id="@+id/network_tab_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/default_white">

        ...........

    </RelativeLayout>
</com.windfindtech.ishanghai.view.SwipeScrollView>

<com.windfindtech.ishanghai.view.DragImageView
    android:id="@+id/iv_drag_adver"
    android:layout_width="40dp"
    android:layout_height="40dp"
    android:layout_gravity="right|top"
    android:src="@drawable/ic_launcher" />
</FrameLayout>