Android Service实现闹钟

1.MainActivity.class中开启服务

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = new Intent(this, LongRunningService.class);
startService(intent);
}
}

2.LongRunningService.class中获取闹钟服务，并定时10s，然后启动AlarmActivity.class

import android.app.AlarmManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.SystemClock;
import android.util.Log;

import java.util.Date;

/**
* Created by admin on 16-5-31.
*/
public class LongRunningService extends Service{
@Override
public IBinder onBind(Intent intent) {
return null;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
new Thread(new Runnable() {
@Override
public void run() {
Log.i("LongRunningService", "executed at " + new Date().toString());
}
}).start();
AlarmManager manager = (AlarmManager) getSystemService(ALARM_SERVICE);
int anHour = 10 * 1000;
long triggerAtTime = SystemClock.elapsedRealtime() + anHour;
Intent i = new Intent(this, AlarmActivity.class);
PendingIntent pi = PendingIntent.getActivity(this, 0, i, 0);
manager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, triggerAtTime, pi);//1min后返回执行
return super.onStartCommand(intent, flags, startId);
}
}

3.AlarmActivity.class中实例化一个对话框，并播放音乐

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class AlarmActivity extends Activity {

MediaPlayer mAlarmMusic;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAlarmMusic = MediaPlayer.create(this,R.raw.alarm);
mAlarmMusic.setLooping(true);
mAlarmMusic.start();
new AlertDialog.Builder(AlarmActivity.this).setTitle("Alarm !!!")
.setMessage("Time Out,GO!")
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
mAlarmMusic.stop();
AlarmActivity.this.finish();
}
}).show();
}
}

实现效果，如下图所示。