public class Alarm2Activity extends AppCompatActivity { private AlarmManager alarmManager; private PendingIntent pendingIntent; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_alarm2); //實例化鬧鐘個管理器 alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE); } //設置鬧鐘（只響一次） public void startAlarmOne(View view){ //獲取當前系統的時間 Calendar calendar=Calendar.getInstance(); int hour=calendar.get(Calendar.HOUR_OF_DAY); int minute=calendar.get(Calendar.MINUTE); //彈出時間對話框（選擇時間） TimePickerDialog timePickerDialog=new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {  @Override  public void onTimeSet(TimePicker timePicker, int i, int i1) {  //獲取當前系統的時間  Calendar c=Calendar.getInstance();  c.set(Calendar.HOUR_OF_DAY,i);  c.set(Calendar.MINUTE,i1);  //打開一個Activity  Intent intent=new Intent();  intent.setAction("com.example.myandroid_27.ALARM");  PendingIntent pendingIntent= PendingIntent.getBroadcast(Alarm2Activity.this,0x101,intent,0);  //設置鬧鐘  alarmManager.set(AlarmManager.RTC_WAKEUP,c.getTimeInMillis(),pendingIntent);  } },hour,minute,true); timePickerDialog.show(); } //設置鬧鐘（在多長時間后鬧鐘響然后繼續計時） public void startAlarmTwo(View view){ //獲取當前系統的時間 Calendar calendar=Calendar.getInstance(); int h=calendar.get(Calendar.HOUR_OF_DAY); int m=calendar.get(Calendar.MINUTE); //彈出時間對話框（選擇時間） TimePickerDialog timePickerDialog=new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {  @Override  public void onTimeSet(TimePicker timePicker, int i, int i1) {  //獲取選擇的鬧鐘時間  Calendar c=Calendar.getInstance();  c.set(Calendar.HOUR_OF_DAY,i);  c.set(Calendar.MINUTE,i1);  //打開一個Activity  Intent intent=new Intent();  intent.setAction("com.example.myandroid_27.ALARM");  pendingIntent = PendingIntent.getBroadcast(Alarm2Activity.this,0x102,intent,0);  //鬧鐘什么時候繼續執行  alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,c.getTimeInMillis(),5000, pendingIntent);  } },h,m,true); timePickerDialog.show(); } //關閉周期鬧鐘 public void startAlarmThree(View view){ alarmManager.cancel(pendingIntent); }}