按住Android按钮可连续循环一个方法
我有一个按钮,我设置了一个ontouchlistener来连续执行一个方法,但当我按住按钮时,它在一次方法调用后停止执行 我的方法基本上是从2到4连续循环 下面是我的代码片段按住Android按钮可连续循环一个方法,android,button,Android,Button,我有一个按钮,我设置了一个ontouchlistener来连续执行一个方法,但当我按住按钮时,它在一次方法调用后停止执行 我的方法基本上是从2到4连续循环 下面是我的代码片段 broadcastButton = (Button) findViewById(R.id.broadcastButton); broadcastButton.setText("Loop"); broadcastButton.setOnTouchListener(new View.OnTouchListener() {
broadcastButton = (Button) findViewById(R.id.broadcastButton);
broadcastButton.setText("Loop");
broadcastButton.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
broadcastmode = 1;
schedulePeriodicMethod();
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
break;
case MotionEvent.ACTION_UP:
broadcastmode = 0;
stopPeriodicMethod();
}
return true;
}
});
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
}
public void stopPeriodicMethod() {
exHandler.removeCallbacks(execution);
}
private Runnable execution = new Runnable() {
@Override
public void run() {
connectDevice(flag);
serialSend("C");
flag++;
if (flag > 4)
flag = 2;
}
};
需要帮助说明我哪里做错了,程序没有循环我认为schedulePeriodicMethod;将调用此一次:
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
}
postDelayed将运行一次,因此需要从方法本身调用它
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
schedulePeriodicMethod();
}
我认为计划周期法;将调用此一次:
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
}
postDelayed将运行一次,因此需要从方法本身调用它
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
schedulePeriodicMethod();
}
这是因为MotionEvent.ACTION\u DOWN和MotionEvent.ACTION\u同时移动火。按下按钮时,请使用此方法
MOVE_THRESHOLD_DP = 20 * getActivity().getResources()
.getDisplayMetrics().density;
@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
final int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.d("TAG", "ON Down" + onMoveOccur);
onMoveOccur = false;
mDownPosX = event.getX();
mDownPosY = event.getY();
//your code
break;
case MotionEvent.ACTION_UP:
Log.d("TAG", "ON UP==" + onMoveOccur);
if (!onMoveOccur) {
//your code
}
break;
case MotionEvent.ACTION_MOVE:
if (Math.abs(event.getX() - mDownPosX) > MOVE_THRESHOLD_DP
|| Math.abs(event.getY() - mDownPosY) > MOVE_THRESHOLD_DP) {
onMoveOccur = true;
}
break;
default:
break;
}
return false;
}
});
这是因为MotionEvent.ACTION\u DOWN和MotionEvent.ACTION\u同时移动火。按下按钮时,请使用此方法
MOVE_THRESHOLD_DP = 20 * getActivity().getResources()
.getDisplayMetrics().density;
@Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
final int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.d("TAG", "ON Down" + onMoveOccur);
onMoveOccur = false;
mDownPosX = event.getX();
mDownPosY = event.getY();
//your code
break;
case MotionEvent.ACTION_UP:
Log.d("TAG", "ON UP==" + onMoveOccur);
if (!onMoveOccur) {
//your code
}
break;
case MotionEvent.ACTION_MOVE:
if (Math.abs(event.getX() - mDownPosX) > MOVE_THRESHOLD_DP
|| Math.abs(event.getY() - mDownPosY) > MOVE_THRESHOLD_DP) {
onMoveOccur = true;
}
break;
default:
break;
}
return false;
}
});
删除线程休眠,因为它在这里什么都不做,最多会使应用跳过6帧,最坏的情况下甚至会使一些设备崩溃,因为它会使主线程停止100毫秒
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
让shadulePeriodicMethod称之为“自我”
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
if (broadcastmode == 1){
schedulePeriodicMethod();
}
}
删除线程休眠,因为它在这里什么都不做,最多会使应用跳过6帧,最坏的情况下甚至会使一些设备崩溃,因为它会使主线程停止100毫秒
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
让shadulePeriodicMethod称之为“自我”
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
if (broadcastmode == 1){
schedulePeriodicMethod();
}
}
将起始函数从
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
}
到
您的runnable可以:
private Runnable execution = new Runnable() {
@Override
public void run() {
if (broadcastmode ==0) return;
connectDevice(flag);
serialSend("C");
flag++;
if (flag > 4)
flag = 2;
//call the runnable itself again, to keep execution going
exHandler.postDelayed(execution, 100);
}
};
而且,正如斯加尔所说,你的Thread.sleep是完全无用的。顺便说一句,Android中的Thread.sleep不是一个好的实践,尤其是在UI线程上
public void schedulePeriodicMethod() {
exHandler.postDelayed(execution, 100);
}
到
您的runnable可以:
private Runnable execution = new Runnable() {
@Override
public void run() {
if (broadcastmode ==0) return;
connectDevice(flag);
serialSend("C");
flag++;
if (flag > 4)
flag = 2;
//call the runnable itself again, to keep execution going
exHandler.postDelayed(execution, 100);
}
};
而且,正如SGal所说,你的Thread.sleep是完全无用的。顺便说一句,Android中的Thread.sleep不是一个好的实践,尤其是在UI线程上
//create a handler, override handle message of Handler
private Handler myHandler = new Handler(){
@Override
public void handleMessage(Message msg) {
// do yo stuffs here like UI update etc.
//create a new message since a message will be consumed once as it //delivered by handler after the delay
Message message = new Message();
message.what = msg.what;
// send the new message with handler
myHandler.sendMessageDelayed(message, 150);
// 150 is time in milliseconds after which handler will give callback
}
};
//让我们在触摸视图时调用处理程序,将ontouch listener设置为//所需的视图
//在触摸视图时,创建一条新消息,并将其//传递给处理程序
@Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Message message = new Message();
myHandler.sendMessage(message);
break;
// on action up of on touch of the view, remove the messages and call backs
//case MotionEvent.ACTION_UP:
myHandler.removeCallbacksAndMessages(null);
break;
}
return false;
}
下面是连续循环方法的简单方法
//create a handler, override handle message of Handler
private Handler myHandler = new Handler(){
@Override
public void handleMessage(Message msg) {
// do yo stuffs here like UI update etc.
//create a new message since a message will be consumed once as it //delivered by handler after the delay
Message message = new Message();
message.what = msg.what;
// send the new message with handler
myHandler.sendMessageDelayed(message, 150);
// 150 is time in milliseconds after which handler will give callback
}
};
//让我们在触摸视图时调用处理程序,将ontouch listener设置为//所需的视图
//在触摸视图时,创建一条新消息,并将其//传递给处理程序
@Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
Message message = new Message();
myHandler.sendMessage(message);
break;
// on action up of on touch of the view, remove the messages and call backs
//case MotionEvent.ACTION_UP:
myHandler.removeCallbacksAndMessages(null);
break;
}
return false;
}
尝试调用方法本身。当我按下按钮尝试调用方法本身时,应用程序崩溃。当我再次按下按钮尝试调用该方法时,应用程序崩溃。当我按下按钮时,应用程序崩溃。您可以发布stacktrace PLZOFSource!我真傻。postDelayed未阻塞,可能会出现堆栈溢出异常。你应该从runnable中调用该方法,但是我看到@Apollo已经发布了正确的答案。我尝试再次调用该方法,一旦我按下按钮,应用程序就会崩溃。你可以发布stacktrace plzofcource!我真傻。postDelayed未阻塞,可能会出现堆栈溢出异常。你应该从runnable调用这个方法,但是我看到@Apollo已经发布了正确的答案。这种方法有效。谢谢它执行得太快了,所以我把执行间隔调大了。但是,如果在再次执行/循环之前需要等待某个事件触发,我该如何做呢?在回调时设置一个条件。但是如果你有多个循环条件,也许你并不真的需要一个循环,而是一个想要的执行?因此,只要在需要时删除recall&call schedulePeriodicMethod即可。这种方法有效。谢谢它执行得太快了,所以我把执行间隔调大了。但是,如果在再次执行/循环之前需要等待某个事件触发,我该如何做呢?在回调时设置一个条件。但是如果你有多个循环条件,也许你并不真的需要一个循环,而是一个想要的执行?因此,只要在需要时删除recall&call schedulePeriodicMethod即可。