1.佈局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
 
>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="設定鬧鐘一次"
        android:onClick="setAlarmone"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="設定鬧鐘週期"
 

        android:onClick="setAlarmcycle"/>

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="取消設定鬧鐘週期"
        android:onClick="mcycle"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 

    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_ring"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="起床了"
        android:textSize="30sp"/>

    <TimePicker
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/timePicker2" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="關閉鬧鐘"
        android:onClick="close"/>
</LinearLayout>


2.MainActivity .java程式碼
public class MainActivity extends AppCompatActivity {

    private AlarmManager alarmManager;
    private PendingIntent pendingIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //獲取鬧鐘管理者
        alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    }

    public void setAlarmone(View view) {
        Calendar calendar = Calendar.getInstance();
        final int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);
        TimePickerDialog timePickerDialog = new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
            @Override
            public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                Calendar c = Calendar.getInstance();
                c.set(Calendar.HOUR_OF_DAY, hourOfDay);
                c.set(Calendar.MINUTE, minute);
                Intent intent = new Intent();
                intent.setAction("com.zking.g158231_android28.RING");
                PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0x100, intent, 0);
                alarmManager.set(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), pendingIntent);
            }
        }, hour, minute, true);
        timePickerDialog.show();
    }

    public void setAlarmcycle(View view) {
        Calendar calendar = Calendar.getInstance();
        final int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);
        TimePickerDialog timePickerDialog = new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
            @Override
            public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                Calendar c = Calendar.getInstance();
                c.set(Calendar.HOUR_OF_DAY, hourOfDay);
                c.set(Calendar.MINUTE, minute);
                Intent intent = new Intent();
                intent.setAction("com.zking.g158231_android28.RING");
                pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0x102, intent, 0);
                //每5秒掉一次鬧鐘
                alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(),5000, pendingIntent);
            }
        }, hour, minute, true);
        timePickerDialog.show();
    }
    public void mcycle(View view){
        alarmManager.cancel(pendingIntent);
    }
}

3.廣播接受著程式碼
public class Ring extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        if ("com.zking.g158231_android28.RING".equals(intent.getAction())){
            Intent intent1=new Intent(context,RingActivity.class);
            intent1.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(intent1);
        }
    }
}


4.鬧鐘頁面程式碼
public class RingActivity extends AppCompatActivity {

    private MediaPlayer mediaPlayer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ring);
        //播放音樂
        mediaPlayer = MediaPlayer.create(this, R.raw.aaa);
        mediaPlayer.start();
    }
    public void close(View view){
        mediaPlayer.stop();
        finish();
    }
}


5.在清單檔案application下注冊廣播
 <receiver android:name=".Ring">
            <intent-filter>
                <action android:name="com.zking.g158231_android28.RING"></action>
            </intent-filter>
        </receiver>