android应用自动化过程中，会遇见需要长按并拖动的场景，例如类似UC浏览器中，长按某个导航中的图标，使其处于可移动状态，然后再将其移动到另一 个地方，与其它导航图标换个位置，在robotium中有个drag(float fromX, float toX, float fromY, float toY,int stepCount)方法，但由于drag没有长按这个步骤，因此不能使应用处于可移动的状态，是没法完成这样的常见而简单的操作的。

drag方法源码实现如下：

    public void drag(float fromX, float toX, float fromY, float toY,  
            int stepCount) {  
        long downTime = SystemClock.uptimeMillis();  
        long eventTime = SystemClock.uptimeMillis();  
        float y = fromY;  
        float x = fromX;  
        float yStep = (toY - fromY) / stepCount;  
        float xStep = (toX - fromX) / stepCount;  
        MotionEvent event = MotionEvent.obtain(downTime, eventTime,MotionEvent.ACTION_DOWN, fromX, fromY, 0);  
        try {  
            inst.sendPointerSync(event);  
        } catch (SecurityException ignored) {}  
        for (int i = 0; i < stepCount; ++i) {  
            y += yStep;  
            x += xStep;  
            eventTime = SystemClock.uptimeMillis();  
            event = MotionEvent.obtain(downTime, eventTime,MotionEvent.ACTION_MOVE, x, y, 0);  
            try {  
                inst.sendPointerSync(event);  
            } catch (SecurityException ignored) {}  
        }  
        eventTime = SystemClock.uptimeMillis();  
        event = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_UP,toX, toY, 0);  
        try {  
            inst.sendPointerSync(event);  
        } catch (SecurityException ignored) {}  
    }  

可以看出其实是通过MotionEvent的ACTION_DOWN模拟屏幕按下操 作，ACTION_MOVE模拟手势在屏幕上滑动，ACTION_UP模拟手势离开屏幕，从而完成整个拖动过程，而且其实robotium中的各种点击类 方法也都是通过模拟不同的手势完成的。

因此要想完成长按并拖动的操作，只要在ACTION_DOWN之后，停留一段时间即可模拟长按操作。

    /** 
         * 实现将一个视图拖动到另一个视图所在的位置 
         * @param viewFrom   起始View 
         * @param viewTo     终点View 
         * @throws Exception 
         */  
        public void clickLongAndDrag(View viewFrom,View viewTo) throws Exception {  
            //获得视图View中手机屏幕上的绝对x、y坐标  
            final int[] location = new int[2];    
            final int[] location2 = new int[2];   
            viewFrom.getLocationOnScreen(location);  
            viewTo.getLocationOnScreen(location2);  
              
            float xStart=location[0];  
            float yStart=location[1];  
              
            float xStop=location2[0];  
            float yStop=location2[1];  
            Log.i(TAG, "xStart:"+String.valueOf(xStart));  
            Log.i(TAG, "yStart:"+String.valueOf(yStart));  
            Log.i(TAG, "xStop:"+String.valueOf(xStop));  
            Log.i(TAG, "yStop:"+String.valueOf(yStop));  
              
            long downTime = SystemClock.uptimeMillis();  
            long eventTime = SystemClock.uptimeMillis();  
              
            try{  
                MotionEvent event = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_DOWN, xStart+10f, yStart+10f, 0);  
                inst.sendPointerSync(event);  
                //event = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_MOVE, xStart+10f+1.0f, yStart+10f+1.0f, 0);  
                //inst.sendPointerSync(event);  
                //Thread.sleep(1000);  
                //延迟一秒，模拟长按操作  
                eventTime = SystemClock.uptimeMillis() + 1000;  
                //xStop加了10点坐标，获得的View坐标需根据应用实际情况稍做一点调整  
                event = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_MOVE, xStop+10f, yStop+50f, 0);  
                inst.sendPointerSync(event);  
                eventTime = SystemClock.uptimeMillis() + 1000;  
                //又再小小移动了一次，不这么做的话可以无法激活被测应用状态，导致View移动后又回复到原来位置  
                event = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_MOVE, xStop+10f, yStop+10f, 0);  
                inst.sendPointerSync(event);  
                eventTime = SystemClock.uptimeMillis() + 1000;  
                event = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_UP, xStop+10f, yStop+10f, 0);  
                inst.sendPointerSync(event);  
            }catch (Exception ignored) {  
                // Handle exceptions if necessary  
                }  
        }