Question

我有一个闹钟接收器，每天在特定时间每天在mainActivity中运行：

    public void scheduleAlarm() 
{
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeInMillis(System.currentTimeMillis());
    calendar.set(Calendar.HOUR_OF_DAY, 16);
    calendar.set(Calendar.MINUTE, 25);
    Intent intentAlarm = new Intent(this, AlarmReceiver.class);
    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), PendingIntent.getBroadcast(this,1,  intentAlarm, PendingIntent.FLAG_UPDATE_CURRENT));
}

在另一个名为alarmReceiver的类中我尝试更改textView上下文但它崩溃了......

public class AlarmReceiver extends BroadcastReceiver {
NotificationCompat.Builder mBuilder;

@Override
public void onReceive(Context context, Intent intent) {
    TextView black;

    black = (TextView) ((Activity)context).findViewById(R.id.BlackCounterDisplay);
    black.setText("toto");
}

}

无法找到原因......

Answer 1

如果您look at your stack trace，则会看到ClassCastException，因为传递给Context的{{1}}不是onReceive()。

Answer 2

你创建了你应该在主要活动中检查的全局变量并在onReceive（）中将其设置为true 然后在主要活动上更改文本但是，如果你想要一个警报或期间警报，那就更好了

从另一个类改变textview会崩溃一切

2 个答案: