Android Api Demos登顶之路（三十一）Alarm Controller

这个demo演示了闹钟定时器的用法。功能与TimerTask功能类似，但Alarm 即使在当前应用退出后也可以做到Schedule一个任务在指定的时刻执行。
activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="5dp" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:text="@string/info" />
    <Button 
        android:id="@+id/bt_one_shot"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:layout_gravity="center_horizontal"
        android:text="One shot alarm"/>
    <Button 
        android:id="@+id/bt_repeating"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:layout_gravity="center_horizontal"
        android:text="Start repeating alarm"/>
    <Button 
        android:id="@+id/bt_stop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:layout_gravity="center_horizontal"
        android:text="Stop repeating alarm"/>

</LinearLayout>

OneShotReceiver.java

public class OneShotReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String text="接收到了一个定时器发送的广播";
        Toast.makeText(context,text, 1).show();
    }

}

RepeatingAlarmReceiver.java

public class RepeatingAlarmReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String text="接收到了定时器重复发送的广播";
        Toast.makeText(context,text, 1).show();
    }

}

ManiActivity

public class MainActivity extends Activity implements OnClickListener {
    private Toast toast;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button bt_one_shot = (Button) findViewById(R.id.bt_one_shot);
        Button bt_repeating = (Button) findViewById(R.id.bt_repeating);
        Button bt_stop = (Button) findViewById(R.id.bt_stop);
        bt_one_shot.setOnClickListener(this);
        bt_repeating.setOnClickListener(this);
        bt_stop.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.bt_one_shot:
            oneShotAlarm();
            break;
        case R.id.bt_repeating:
            repeatingAlarm();
            break;
        case R.id.bt_stop:
            stopAlarm();
            break;
        default:
            break;
        }
    }

    private void stopAlarm() {
        Intent intent = new Intent(this, RepeatingAlarmReceiver.class);
        // 创建一个延迟意图,用于定时发送广播
        PendingIntent sender = PendingIntent.getBroadcast(this, 0, intent, 0);

        // 获取闹钟定时器
        AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
        // 取消发送任务
        am.cancel(sender);

        if (toast != null) {
            toast.cancel();
        } else {
            toast=Toast.makeText(this, "已取消发送广播", 1);
            toast.show();
        }

    }

    private void repeatingAlarm() {
        Intent intent = new Intent(this, RepeatingAlarmReceiver.class);
        // 创建一个延迟意图,用于定时发送广播
        PendingIntent sender = PendingIntent.getBroadcast(this, 0, intent, 0);
        // 获取一个相对时间：从开机到当前的毫秒数
        long firstTime=SystemClock.elapsedRealtime();
        firstTime+=5*1000;

        // 获取闹钟定时器
        AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
        // 设置一重复性定时器.
        //闹钟类型表示闹钟在睡眠状态下会唤醒系统并执行提示功能，该状态下闹钟使用相对时间
        am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP, firstTime, 5*1000, sender);

        if (toast != null) {
            toast.cancel();
        } else {
            toast=Toast.makeText(this, "开始计时，5秒后将重复发送广播...", 1);
            toast.show();
        }
    }

    private void oneShotAlarm() {
        Intent intent = new Intent(this, OneShotReceiver.class);
        // 创建一个延迟意图,用于定时发送广播
        PendingIntent sender = PendingIntent.getBroadcast(this, 0, intent, 0);
        // 创建一个定时器，时间间隔为5秒
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());
        // 添加一个时间间隔
        calendar.add(Calendar.SECOND, 5);

        // 获取闹钟定时器
        AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
        // 设置一次性定时器，第一个参数表示闹钟类型，第二个参数表示触发闹钟需等待的时间，第三个参数
        // 表示闹钟响应的动作
        // RTC_WAKEUP表示闹钟在睡眠状态下会唤醒系统并执行提示功能，该状态下闹钟使用绝对时间
        am.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), sender);

        if (toast != null) {
            toast.cancel();
        } else {
            toast=Toast.makeText(this, "开始计时，5秒后将发送广播...", 1);
            toast.show();
        }
    }

}

配置文件

 <!-- android:process=":remote"表示当需要接收广播时自动创建进程 -->
        <receiver android:name="com.fishtosky.alarmcontroller.OneShotReceiver"
            android:process=":remote"></receiver>
        <receiver android:name="com.fishtosky.alarmcontroller.RepeatingAlarmReceiver"
            android:process=":remote"></receiver>