Question

我写了一个应用程序，可以在之前选择的预定时间打开/关闭WiFi。它的工作方式非常简单：从时间选择器中选择时间，然后将其添加即可。它以编程方式从时间选择器获取数据并进行设置和报警。我会为自己的活动写下一个代码，然后首先广播接收者，然后在此代码下写下我的问题。不用担心，我在代码中添加了注释，以便更清晰地阅读和理解

Wifi.class：

public class WiFi extends AppCompatActivity {
private final int TEMP_REQUEST_CODE = 1;
private AlarmManager alarmManager;
private TimePicker timePicker;
private PendingIntent pendingIntent;
private Intent intent;
private Context context;
private Calendar calendar;
Intent alarmIntent;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.wifi_class);
    timePicker = (TimePicker) findViewById(R.id.timePicker1);
    timePicker.setIs24HourView(true);
    setTitle("Set WiFi off/on");
    //store context in global variable
    context = getApplicationContext();
    //creates an intent that will be used in pending intent
    initializeView();
    //creates pending intent
    createAlarmIntent();
    //checks if alarm exists and sets matching text on the screen
    checkAlarmExists();

}

// I got an add button in my toolbar that saves the alarm, same as to delete 
an alarm
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.tick:
            Alarm();
            finish();
            return true;
        case R.id.dismiss:
            cancelAlarm();
        default:
            return super.onOptionsItemSelected(item);
    }
}
//this method initialize intent and stores it into variable, 
WiFiService.class extends BroadcastReceiver
//and all what it has to do is to turn wifi on/off
private void initializeView () {
    intent = new Intent(context, WifiService.class);

    //creating global pendingIntent variable
     pendingIntent = PendingIntent.getBroadcast(context,
            0,
            intent,
            0);
    //creating global alarmManager variable
     alarmManager = (AlarmManager) context.getSystemService(ALARM_SERVICE);
}
//this method gets selected time from timepicker and calls another method to 
create an alarm
private void Alarm() {
     calendar = Calendar.getInstance();
    if (Build.VERSION.SDK_INT >= 23) {
        calendar.set(
                calendar.get(Calendar.YEAR),
                calendar.get(Calendar.MONTH),
                calendar.get(Calendar.DAY_OF_MONTH),
                timePicker.getHour(),
                timePicker.getMinute(), 0
        );

    } else {
        calendar.set(
                calendar.get(Calendar.YEAR),
                calendar.get(Calendar.MONTH),
                calendar.get(Calendar.DAY_OF_MONTH),
                timePicker.getCurrentHour(),
                timePicker.getCurrentMinute(),
                0);
    }
    setAlarm();
}

/**
 * This method sets Alarm that will be executed even in Doze mode and will 
intent WifiServices class,
 * in the result it will turn wifi off or on
 *
 */
private PendingIntent createAlarmIntent() {
     alarmIntent = new Intent(this, WifiService.class);
    return PendingIntent.getBroadcast(this, TEMP_REQUEST_CODE,
            alarmIntent, 0);
}
private void setAlarm() {
//setting alarm
    PendingIntent intent = createAlarmIntent();
    if (Build.VERSION.SDK_INT >= 23) {
        alarmManager.setAlarmClock(new 
AlarmManager.AlarmClockInfo(calendar.getTimeInMillis(), pendingIntent), 
intent);
}
    else {
        alarmManager.setExact(AlarmManager.RTC, calendar.getTimeInMillis(), 
pendingIntent);
    }

    long AlarmMgs = calendar.getTimeInMillis() - 
Calendar.getInstance().getTimeInMillis();
    Toast.makeText(context, "Alarm will be executed in " + AlarmMgs / 1000 / 
60 + "min", Toast.LENGTH_SHORT).show();

}


/**
 * This method should cancel alarm that is being currently set. There is no 
 if/else statement 
 * because it always says that alarm exists (see next method)
 */
private void cancelAlarm() {

    alarmManager.cancel(createAlarmIntent());
    Toast.makeText(context, "Alarm dismissed", Toast.LENGTH_SHORT).show();
    checkAlarmExists();
}

/**
 * This method checks wrether alarm is set or not and assigns that into 
 TextView
 * Unfortunately it always says it exists
 */
private void checkAlarmExists() {

    boolean alarmExists =
            (PendingIntent.getBroadcast(context,
                    0,
                    intent,
                    PendingIntent.FLAG_NO_CREATE)
                    != null);

    TextView alarmSetter = (TextView) findViewById(R.id.alarmSet);
    if (alarmExists) {
        alarmSetter.setText("Alarm is set");

    } else {
        alarmSetter.setText("Alarm is not set yet");
    }
}
    //TODO: (1): Create more than 1 alarm without replacing one before
    //TODO: (2): Cancel one of them, not all of them
    //TODO: (3): Edit those alarms 
}

WifiService类：

public class WifiService extends BroadcastReceiver {

public static final String TAG = "WiFi";

@Override
public void onReceive(Context context, Intent intent) {
//        if 
(intent.getAction().equals("android.intent.action.BOOT_COMPLETED")) 
{

        WifiManager wifiManager = (WifiManager) 
context.getApplicationContext().getSystemService(Context.WIFI_SERVICE);
        Log.v("Wifi", "checked");
        if (wifiManager.isWifiEnabled()) {
            wifiManager.setWifiEnabled(false);
            Toast.makeText(context, "Turning wifi off", 
Toast.LENGTH_SHORT).show();
            Log.v(TAG, "Turned off");
        } else {
            wifiManager.setWifiEnabled(true);
            Toast.makeText(context, "turning wifi on", 
Toast.LENGTH_SHORT).show();
            Log.v(TAG, "turned off");
        }
//        }
    Log.v(TAG, "Works");
}

}

好的，我在代码中留下了3个TODO： 1.我想创建1个或多个警报而不替换现有警报，我要做的就是设置挂起标志以在每次设置警报时更新？ 2.如果我创建了3个警报，我想取消其中一个，指定一个。无论如何，我将这些警报存储在数据库中，所以我的想法是：创建警报->将其添加到数据库->在列表中显示-> 如果已删除->从列表中删除->停用 3.编辑警报。我知道如何编辑数据库中的项目，但是如何编辑预定警报？我的意思是编辑其起火时间。就是要重新创建警报吗？

有人可以回答我的问题吗？预先感谢。

Answer 1

设置闹钟时，您将PendingIntent传递给AlarmManager。 PendingIntent包装Intent。设置警报时，AlarmManager会删除它已安排的与PendingIntent匹配的所有警报。要确定PendingIntent是否匹配，将比较以下内容：

requestCode通话中的PendingIntent.getBroadcast()
Intent
Intent中的类别
Intent
Component中的Intent（程序包名称，类名称）

注意：Intent中的“附加”不进行比较

因此，如果我们想重新安排警报，只需创建一个PendingIntent，其requestCode，ACTION和Component与上一个相同，然后重新设置警报。 AlarmManager将删除上一个并设置新的。

如果要并行安排多个警报，则需要确保requestCode，Component或ACTION不同，否则它们将相互覆盖。

编辑预定的待定计划

1 个答案: