我正在尝试创建一个计时器,一旦onDestroy()
被触发就会在后台启动,一旦计时器达到6小时,SharedPreferences
将用于在应用程序中进行更改。
我想知道......为CountDownTimer
设置onDestroy()
或类似的东西的正确方法是什么。
如果需要,我会回答任何问题。谢谢。
大约一个星期后,一个工作的答案出现了。这个答案包括与如何运行服务有关的内容。在这种情况下,我正在建立一个CountDownTimer
服务。
AndroidManifest.xml中
<service android:name=".TimeService"/>
main activity.Java
import android.content.Intent;
import android.support.v4.content.ContextCompat;
public class MainActivity extends AppCompatActivity {
Intent i;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
i = new Intent(this, TimeService.class);
stopService(i); //To stop the service the next time the app is launched.
}
@Override
protected void onDestroy() {
launchService(); //Launches the service once when app shuts down.
super.onDestroy();
}
public void launchService() { //How to launch the service, depending the phone's API.
if(Build.VERSION.SDK_INT >= 26) {
startForegroundService(new Intent(this, TimeService.class));
}
else{
Intent i;
i = new Intent(this, TimeService.class);
ContextCompat.startForegroundService(this, i);
}
}
}
time service.Java
import android.app.Service;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.CountDownTimer;
import android.os.IBinder;
import android.support.annotation.Nullable;
public class TimeService extends Service {
CountDownTimer cdt = null;
private SharedPreferences pref;
//Things you want SharedPreferences to change.
Intent i;
@Override
public void onCreate() {
i = new Intent(this, TimeService.class);
startService(i);
pref = this.getSharedPreferences("myAppPref", MODE_PRIVATE);
cdt = new CountDownTimer(3600000, 1000) { //One hour timer with one second interval.
@Override
public void onTick(long millisUntilFinished) {
}
@Override
public void onFinish() {
//Whatever you need SharedPreferences to change here.
}
};
cdt.start();
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
}