问题描述
请考虑以下方案(为了更好地理解我的问题).
Consider the following scheme below (for sake of better understanding of my problem).
如您所见，我正在考虑一个由填充包围的列表视图.现在，如果用户按下一个列表视图项，则我提供的操作是浅蓝色背景色.现在，我的应用程序正在处理onTouch事件本身，以确定类似的动作
As you can see, I am considering a list view surrounded by padding. Now, If a user presses a listview item, as the action I have provided it light blue background color. Now, My application is dealing with onTouch Events itself to determine actions like
- 点击
- 从左向右滑动
- 从右向左滑动
这是我的代码.
public boolean onTouch(View v, MotionEvent event) {
if(v == null)
{
mSwipeDetected = Action.None;
return false;
}
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN: {
downX = event.getRawX();
downY = event.getRawY();
mSwipeDetected = Action.Start;
// Find the child view that was touched (perform a hit test)
Rect rect = new Rect();
int childCount = listView.getChildCount();
int[] listViewCoords = new int[2];
listView.getLocationOnScreen(listViewCoords);
int x = (int) event.getRawX() - listViewCoords[0];
int y = (int) event.getRawY() - listViewCoords[1];
View child;
for (int i = 0; i < childCount; i++) {
child = listView.getChildAt(i);
child.getHitRect(rect);
if (rect.contains(x, y)) {
mDownView = child;
break;
}
}
return false; // allow other events like Click to be processed
}
case MotionEvent.ACTION_MOVE: {
upX = event.getRawX();
upY = event.getRawY();
float deltaX=0,deltaY=0;
deltaX = downX - upX;
deltaY = downY - upY;
if(deltaY < VERTICAL_MIN_DISTANCE)
{
setTranslationX(mDownView, -(deltaX));
setAlpha(mDownView, Math.max(0f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / listView.getWidth())));
return false;
}
else
{
forceBringBack(v);
}
return false;
}
case MotionEvent.ACTION_UP:
{
stopX = event.getX();
float stopValueY = event.getRawY() - downY;
float stopValue = stopX - downX;
if(!mDownView.isPressed())
{
forceBringBack(mDownView);
return false;
}
boolean dismiss = false;
boolean dismissRight = false;
if(Math.abs(stopValue)<10)
{
mSwipeDetected = Action.Start;
}
else
{
mSwipeDetected = Action.None;
}
String log = "";
Log.d(log, "Here is Y" + Math.abs(stopValueY));
Log.d(log, "First Comparison of Stop Value > with/4" + (Math.abs(stopValue) > (listView.getWidth() /4)));
Log.d(log, "Second Comparison " + (Math.abs(stopValueY)<VERTICAL_MIN_DISTANCE));
Log.d(log, "Action Detected is " + mSwipeDetected + " with Stop Value " + stopValue);
if((Math.abs(stopValue) > (listView.getWidth() /4))&&(Math.abs(stopValueY)<VERTICAL_MIN_DISTANCE))
{
dismiss = true;
dismissRight = stopValue > 0;
if(stopValue>0)
{
mSwipeDetected = Action.LR;
}
else
mSwipeDetected = Action.RL;
}
Log.d(log, "Action Detected is " + mSwipeDetected + " with Stop Value after dissmiss" + stopValue);
if(dismiss)
{
if(dismissRight)
mSwipeDetected = Action.LR;
else
mSwipeDetected = Action.RL;
animate(mDownView)
.translationX(dismissRight ? listView.getWidth() : - listView.getWidth())
.alpha(0)
.setDuration(mAnimationTime)
.setListener(new AnimatorListenerAdapter() {
public void onAnimationEnd(Animator animation)
{
}
});
}
else
{
animate(mDownView)
.translationX(0)
.alpha(1)
.setDuration(mAnimationTime)
.setListener(null);
}
break;
}
}
return false;
}
如您所见，我在MotionEvent.ACTION_UP中确定已执行的动作，并相应地设置Enum Action的值.如果用户未越过列表视图边界，则此逻辑就像一个超级按钮.
As you can see, I determine the performed action in MotionEvent.ACTION_UP and set the value of Enum Action accordingly. This logic works like a charm if the user does not crosses the list view boundary.
现在，如果用户在滑动(或特别地)沿列表项移动手指(从蓝色变为橙色)时，MotionEvent.ACTION_UP将不会提供给listview，这将导致我的代码无法做出决定，并且由于translationX()方法和setAlpha()的缘故，由于在这种情况下没有确定操作，因此该特定列表项将变为空白.
Now, if the user, while sliding (or specifically), moving his finger along the list item moves from blue to orange, the MotionEvent.ACTION_UP would not be given to listview, which causes my code not to make a decision and due to translationX() method and setAlpha(), since no Action is ever determined in this case, that particular list item gets blank.
问题不会在这里停止，因为，我并不是每次都在夸大视图，每次都会导致相同的translationX()行被夸大，从而导致多次出现空白/白名单项目.
The problem does not stops here, since, I am not inflating view each time, same translatedX() row gets inflated each time leading to multiple occurance of a blank/white list item.
有什么办法可以做到，即使我没有遇到MotionEvent.ACTION_UP，我仍然可以做出一些决定?
Is there anything possible to do so that even if I didn't encounter MotionEvent.ACTION_UP, I could still make some decison ?
推荐答案
您应该在case MotionEvent.ACTION_DOWN:中使用return true;，以便处理MotionEvent.ACTION_UP.
You should return true; in case MotionEvent.ACTION_DOWN:, so the MotionEvent.ACTION_UP will be handled.
如 View.OnTouchListener 所述:
如果侦听器已经使用了事件，则为真，否则为false.
True if the listener has consumed the event, false otherwise.
MotionEvent.ACTION_UP在MotionEvent.ACTION_DOWN出现之前不会被调用，对此的逻辑解释是，如果ACTION_UP从未出现过，则ACTION_UP不可能出现.
MotionEvent.ACTION_UP Won't get called until the MotionEvent.ACTION_DOWN occurred, a logical explanation for this is that it's impossible for an ACTION_UP to occur if an ACTION_DOWN never occurred before it.
此逻辑使开发人员可以在ACTION_DOWN之后阻止其他事件.
This logic enables the developer to block further events after ACTION_DOWN.
这篇关于不调用MotionEvent.ACTION_UP的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！