public class TestService extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final Intent service=new Intent(getApplicationContext(),MessageListener.class);
Log.v("Test", "Going to start service");
startService(service);
Log.v("Test", "service started?");
}
}
public class MessageListener extends Service {
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.v("Test", "Start Cmd");
intent.setAction("Started");
new Thread(new Runnable() {
@Override
public void run() {
for(int i=100;i<200;i++){
Log.v("Test",i+"");
}
}
}).start();
return START_STICKY;
}
@Override
public void onCreate() {
super.onCreate();
Log.v("Test", "Create");
}
我希望它会打印出来:
Start Service
create
Start cmd
print 1->100
Service Started.
但我得到了
Start Service
Service Started.
create
Start cmd
prints 1->100
为什么?
我发现问题是由异步引起的。在父方法完成后将调用startService。 解决方案是:
public class TestService extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Intent service=new Intent(getApplicationContext(),MessageListener.class);
startService(service);
mCheckerHandler.sendEmptyMessageDelayed(MSG_CHECK_SERVICE_RUNNING, 100);
}
private static final int MSG_CHECK_SERVICE_RUNNING = 0x001122;
private Handler mCheckerHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
if (msg.what == MSG_CHECK_SERVICE_RUNNING) {
if (checkServiceRunning()) {
//Do something
} else {
//Send another message to check in the next 100ms
sendEmptyMessageDelayed(MSG_CHECK_SERVICE_RUNNING, 100);
}
}
};
};
}
谢谢你们所有人。特别是对Binh先生:)
答案 0 :(得分:2)
那是因为线程在“伪”并行执行,因此在计数器线程获得任何CPU时间之前调用Log.v("Test", "service started?");
。
“Pseudo” - 并行,因为大多数手机没有超过1个CPU,因此无法并行计算,因此它们只能从一个线程切换到另一个线程。您可以在Wikipedia或您喜欢的任何其他来源上阅读有关线程的更多信息。