我有一个活动类,在其中有一个静态标志,假设为
public static volatile flag = false;
在类中,我启动了一个线程,该线程检查标志并执行不同的操作。
我还有一个广播接收器,用于将标志设置为true或false。
我认为volatile会强制将标志设置为最近的值。但是我可以看到我的广播接收器将静态标志设置为true,但我的线程仍然将其视为false。
我错过了一些基本的东西吗?任何帮助都将不胜感激!
简化代码(已更新)-因此,该标志应在一分钟后更改为true。但它从未这样做。但来自广播接收器的消息显示已将其更改为true
TestappActivity.java:
package com.test;
import java.util.Calendar;
import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
public class TestappActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent intent0 = new Intent(this, TestService.class);
this.startService(intent0);
Intent intent = new Intent(this, TestReceiver.class);
AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
PendingIntent sender = PendingIntent.getBroadcast(this,
1, intent,
PendingIntent.FLAG_UPDATE_CURRENT);
Calendar slot = Calendar.getInstance();
int min = slot.get(Calendar.MINUTE);
slot.set(Calendar.MINUTE, min+1);
am.set(AlarmManager.RTC_WAKEUP, slot.getTimeInMillis(), sender);
}
}
TestService.java:
package com.test;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
public class TestService extends Service {
private static final String TAG = "TestService";
public static volatile boolean flag = false;
private MyTopThread mTopThread;
public TestService() {
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
}
@Override
public void onDestroy() {
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
protect();
// We want this service to continue running until it is explicitly
// stopped, so return sticky.
return START_STICKY;
}
/**
* Run protection
*
*/
private void protect() {
mTopThread = new MyTopThread();
mTopThread.start();
}
private class MyTopThread extends Thread {
@Override
public void run() {
while (true) {
try {
Thread.sleep(150);
Log.d(TAG, "Flag is " + TestService.flag);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
TestReceiver.java:
package com.test;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class TestReceiver extends BroadcastReceiver {
final static private String TAG = "TestReceiver";
@Override
public void onReceive(Context context, Intent intent) {
Log.d(TAG, "onReceive is triggered ...");
TestService.flag = true;
Log.d(TAG, "flag is changed to " + TestService.flag);
}
}
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.test"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".TestappActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".TestService" />
<receiver
android:name=".TestReceiver"
android:process=":remote" >
</receiver>
</application>
</manifest>
flag
的值被改变了。 - Ted Hopp