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，用于实现快讯栏目、手机报的排序
* @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
}
}