Question

这里有两个问题。我尝试让用户选择特定时间让应用提醒用户使用应用。一旦用户设定时间说晚上8点。通知应该每天弹出。但是，在我使用

之后

"NotificationManager" and "Notification"

首先，没有任何弹出窗口。例如，现在是AU的上午1:19，然后，我将此应用设置为凌晨1点20分，以便在状态栏中显示通知作为测试。

其次，如果在我的 TabBar 类中我使用

nm.cancel(getIntent().getExtras().getInt("NotifID"));

它将获得空指针异常

这是我的代码：

TabBar.class

NotificationManager nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
nm.cancel(getIntent().getExtras().getInt("NotifID"));

Notification.class

package com.example.tabpro;

import java.util.Calendar;
import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TimePicker;

public class SettingNotification extends Activity{

TimePicker timePicker;

 @Override
 public void onCreate(Bundle savedInstanceState){
     super.onCreate(savedInstanceState);
     setContentView(R.layout.setting_notification);

     Button btnset = (Button) findViewById(R.id.btnSetAlarm);
     btnset.setOnClickListener(new View.OnClickListener(){

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            timePicker = (TimePicker) findViewById(R.id.timePicker_settime);

            AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);

            Calendar calendar = Calendar.getInstance();  
            calendar.set(Calendar.HOUR_OF_DAY, timePicker.getCurrentHour());
            calendar.set(Calendar.MINUTE, timePicker.getCurrentMinute());
            calendar.set(Calendar.SECOND, 0);

            Intent i = new Intent("com.example.tabpro.DisplayNotification");
            Intent i2 = new Intent(SettingNotification.this, TabBar.class);
            i.putExtra("NotifID", 1);                                

            PendingIntent displayIntent = PendingIntent.getActivity(
                getBaseContext(), 0, i, 0); 

            alarmManager.set(AlarmManager.RTC_WAKEUP, 
                    calendar.getTimeInMillis(), displayIntent);
            startActivity(i2);

        }


     });



 }


}

DisplayNotification.class

package com.example.tabpro;

import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;

public class DisplayNotification extends Activity {

 @Override
 public void onCreate(Bundle savedInstanceState){
     super.onCreate(savedInstanceState);
     int notifID = getIntent().getExtras().getInt("NotifID");

     Intent i = new Intent("com.example.tabpro.TabBar");

     i.putExtra("NotifID", notifID); 

     PendingIntent detailsIntent = PendingIntent.getActivity(this, 0, i, 0);

     NotificationManager nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
     Notification notif = new Notification(R.drawable.ic_launcher, "Time's up!", System.currentTimeMillis());

     CharSequence from = "AlarmManager - Time's up!";
     CharSequence message = "This is your alert, courtesy of the AlarmManager";        
     notif.setLatestEventInfo(this, from, message, detailsIntent);       

     finish();
 }

}

Answer 1

您需要在NotificationManager上致电notify()以实际显示通知。由于您从未调用此方法，因此永远不会显示您的通知。

您的NullPointerException可能是一个不同的问题。为此，你应该自己做一些调试。首先，您需要确定什么是null。然后确定它为null的原因并修复它。在您的代码中，导致TabBar中的NPE的最可能候选者是nm，getIntent()和getExtras()。

Answer 2

希望这会有所帮助：您需要调用notify（）方法在设备的通知栏中显示通知。

以下是代码：

Notification notification;
PendingIntent contentIntent = PendingIntent.getActivity(context, 0,new Intent(context,      YourActivity.class), 0);
NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
notification = builder.setContentIntent(contentIntent)
                .setSmallIcon(icon).setTicker(yourappname).setWhen(0)
                .setAutoCancel(true).setContentTitle(yourappname)
                .setContentText(yourmessage).build();
notificationManager.notify(0, notification);

android状态栏中没有通知弹出窗口

2 个答案: