Android 定时器处理程序
我正在使用这段代码：
public class newtimer extends Activity {
private Timer myTimer;
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
@Override
public void run() {
TimerMethod();
}
}, 0, 1000);
}
int number = 0;
private void TimerMethod()
{
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
Toast.makeText(this, "TimerMethod Running "+number, Toast.LENGTH_SHORT).show();
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
//This method runs in the same thread as the UI.
//Do something to the UI thread here
Toast.makeText(getBaseContext(), "UI Thread Running "+number, Toast.LENGTH_SHORT).show();
}
};
}
当我运行它时，我在 logcat 中收到此异常：
09-06 21:39:39.701: ERROR/AndroidRuntime(1433): java.lang.RuntimeException: 无法在未调用 Looper.prepare() 的线程内创建处理程序
I am using this code:
public class newtimer extends Activity {
private Timer myTimer;
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
@Override
public void run() {
TimerMethod();
}
}, 0, 1000);
}
int number = 0;
private void TimerMethod()
{
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
Toast.makeText(this, "TimerMethod Running "+number, Toast.LENGTH_SHORT).show();
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
//This method runs in the same thread as the UI.
//Do something to the UI thread here
Toast.makeText(getBaseContext(), "UI Thread Running "+number, Toast.LENGTH_SHORT).show();
}
};
}
When i run it i get this exception in logcat:
09-06 21:39:39.701: ERROR/AndroidRuntime(1433): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
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评论（1）
我认为问题出在 TimerMethod 函数中的
Toast.makeText(this, "TimerMethod Running "+number, Toast.LENGTH_SHORT).show();- 您无法调用任何相关函数从工作线程到 UI。既然在UI线程中运行的部分已经有一个Toast了，为什么在TimerMethod中还要再有一个呢？对于调试，我建议尽可能使用 Log 而不是 Toast。
I would assume the problem is with the
Toast.makeText(this, "TimerMethod Running "+number, Toast.LENGTH_SHORT).show();in your TimerMethod function - you can't call any functions pertaining to the UI from worker threads. Since you already have a Toast in the portion that runs in the UI thread, why do you have another one in TimerMethod?For debugging, I would recommend using Log as much as possible instead of Toast.