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);
 //实例化闹钟个管理器
 alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

 }

 //设置闹钟（只响一次）
 public void startAlarmOne(View view){
 //获取当前系统的时间
 Calendar calendar=Calendar.getInstance();
 int hour=calendar.get(Calendar.HOUR_OF_DAY);
 int minute=calendar.get(Calendar.MINUTE);

 //弹出时间对话框（选择时间）
 TimePickerDialog timePickerDialog=new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
  @Override
  public void onTimeSet(TimePicker timePicker, int i, int i1) {
  //获取当前系统的时间
  Calendar c=Calendar.getInstance();
  c.set(Calendar.HOUR_OF_DAY,i);
  c.set(Calendar.MINUTE,i1);
  //打开一个Activity
  Intent intent=new Intent();
  intent.setAction("com.example.myandroid_27.ALARM");
  PendingIntent pendingIntent= PendingIntent.getBroadcast(Alarm2Activity.this,0x101,intent,0);
  //设置闹钟
  alarmManager.set(AlarmManager.RTC_WAKEUP,c.getTimeInMillis(),pendingIntent);
  }
 },hour,minute,true);
 timePickerDialog.show();
 }
 //设置闹钟（在多长时间后闹钟响然后继续计时）
 public void startAlarmTwo(View view){
 //获取当前系统的时间
 Calendar calendar=Calendar.getInstance();
 int h=calendar.get(Calendar.HOUR_OF_DAY);
 int m=calendar.get(Calendar.MINUTE);
 //弹出时间对话框（选择时间）
 TimePickerDialog timePickerDialog=new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
  @Override
  public void onTimeSet(TimePicker timePicker, int i, int i1) {
  //获取选择的闹钟时间
  Calendar c=Calendar.getInstance();
  c.set(Calendar.HOUR_OF_DAY,i);
  c.set(Calendar.MINUTE,i1);
  //打开一个Activity
  Intent intent=new Intent();
  intent.setAction("com.example.myandroid_27.ALARM");
  pendingIntent = PendingIntent.getBroadcast(Alarm2Activity.this,0x102,intent,0);
  //闹钟什么时候继续执行
  alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,c.getTimeInMillis(),5000, pendingIntent);
  }
 },h,m,true);
 timePickerDialog.show();
 }
 //关闭周期闹钟
 public void startAlarmThree(View view){
 alarmManager.cancel(pendingIntent);
 }
}