我的应用程序正在强制关闭什么？线程存在一些错误。但是我无法弄清楚吗？

Question

public class MainActivity extends Activity {
private Button Start, Reset, Stop;
private EditText stop_watch, lblDate, lblTime;
public MainActivity() {
init();
}
private final UpdateClockThread ucThread = new UpdateClockThread();
private final StopwatchThread swThread = new StopwatchThread();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Start = (Button)findViewById(R.id.button1);
Stop = (Button)findViewById(R.id.button3);
Reset = (Button)findViewById(R.id.button2);
stop_watch = (EditText)findViewById(R.id.editText3);
lblTime = (EditText)findViewById(R.id.editText2);
lblDate = (EditText)findViewById(R.id.editText1);
Start.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
startactionPerformed();
}
});
Stop.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
stopactionPerformed();
}
});
Reset.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
resetactionPerformed();
}
});
}
public void init() {
swThread.setDaemon(true);
ucThread.setDaemon(true);
swThread.start();
ucThread.start();
}
/** Listens to the Start/Stop/Resume button. */
void startactionPerformed() {
swThread.go();
//init();
}
void stopactionPerformed() {
swThread.noGo();
}
void resetactionPerformed() {
swThread.reset();
}
/** A thread that updates the current date & time. */
private class UpdateClockThread extends Thread {
/** The actual work of the thread. */
public void run() {
while (true) {
lblTime.setText("ampm");
Calendar now = Calendar.getInstance();
String month = Integer.toString(now.get(Calendar.MONTH)+1);
String date = Integer.toString(now.get(Calendar.DAY_OF_MONTH));
String year = Integer.toString(now.get(Calendar.YEAR));
String hour = Integer.toString(now.get(Calendar.HOUR));
if (hour.equals("0")) hour = "12";
String minute = Integer.toString(now.get(Calendar.MINUTE));
if (minute.length() == 1) minute = "0" + minute;
String second = Integer.toString(now.get(Calendar.SECOND));
if (second.length() == 1) second = "0" + second;
String ampm = now.get(Calendar.AM_PM) == Calendar.AM ? "AM" : "PM";
lblDate.setText(month + "/" + date + "/" + year);
lblTime.setText(hour + ":" + minute + ":" + second + " " + ampm);
try {
sleep(500);
} catch (InterruptedException e) {} 
}
}
}
/** A thread that keeps track of the stop watch & updates
* the display accordingly.
*/
class StopwatchThread extends Thread {
/** Whether or not stop watch is running. */
private boolean going = false;
/** Stores elapsed milliseconds of previous runs. */
private long prevElapsed = 0;
/** Stores beginning time of this run. */
private Date startDate = new Date();
/** Returns elapsed time in milliseconds.
*@return The elapsed time
*/
private long elapsedTime() {
return prevElapsed + (going ? new Date().getTime() - startDate.getTime() : 0);
}
/** Changes the number of elapsed milliseconds into a string.
*@param time Number of elapsed milliseconds
*@return The elapsed time as a string.
*/
private String msToString(long time) {
String ms, sec, min;
if (time % 10 >= 5) //round to nearest hundredth
time += 5;
ms = Long.toString(time % 1000);
while (ms.length() < 3)
ms = "0" + ms;
ms = ms.substring(0, ms.length() - 1);
time /= 1000;
sec = Long.toString(time % 60);
if (sec.length() == 1) sec = "0" + sec;
time /= 60;
min = Long.toString(time);
return min + ":" + sec + "." + ms;
}
/** Called when the stop watch is to go.
*/
public void go() {
startDate = new Date();
going = true;
}
/** Called when the stop watch is to stop.
*/
public void noGo() {
prevElapsed = elapsedTime();
going = false;
}
/** Resets the stop watch.
*/
public void reset() {
going = false;
prevElapsed = 0;
}
/** Adds a lap to the list.
*/
/** Main code of the thread.
*/
public void run() {
while (true) {
stop_watch.setText(msToString(elapsedTime()));
yield();
}
}
}
}

我的应用程序正在强制关闭什么？线程有一些错误。但我想不通？

Answer 1

尝试通过活动的runOnUiThread方法中的线程与UI进行所有交互http://developer.android.com/reference/android/app/Activity.html#runOnUiThread%28java.lang.Runnable%29

编辑

private class UpdateClockThread extends Thread {
public void run() {
/* Do somthing expensive */
......
/* Update UI */
MainActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
/* Do UI update */;
lblTime.setText("ampm");
......
}
});
}
}

Answer 2

您应该在您的开发人员机器上运行adb-logcat。通常，如果强制关闭，则会在日志中显示回溯。

Answer 3

您的类StopwatchThread包含以下行：

stop_watch.setText(msToString(elapsedTime()));

这将不起作用，UpdateClockThread中的UI更新也不会起作用。这是因为您无法从后台线程修改UI。您的后台线程应该是：

• 向在UI线程上创建的Handler发送消息，以便Handler对UI进行更新，或者
• 您可以将runnable传递到执行UI更新的runOnUiThread中