状态栏中的android无通知弹出窗口

这里有两个问题。我尝试让用户选择一个特定的时间来提醒用户使用应用程序。一旦用户设置了时间，就说是晚上8:00。通知应该每天都会弹出。然而，在我使用

"NotificationManager" and "Notification"

首先，没有弹出窗口。例如，现在是AU的凌晨1:19，然后，我将此应用程序设置为凌晨1:20，以在状态栏中显示通知作为测试

其次，如果我在TabBar类中使用

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

它将得到一个空指针异常

这是我的密码：

塔巴级

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

通知类

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);

        }


     });



 }


}

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();
 }

}

DisplayNotification.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);

        }


     });



 }


}

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();
 }

}

您需要调用

NotificationManager

来实际显示通知。由于您从未调用此方法，因此不会显示通知

您的NullPointerException可能是另一个问题。为此，您应该自己进行一些调试。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，最有可能导致

TabBar

中出现NPE的是

nm

、

getIntent（）

、和

getExtras（）

，希望这对您有所帮助： 您需要调用notify（）方法在设备的通知托盘中显示通知

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);

使用

set（）

可以给出过去的时间，如果小时/分钟/秒是今天的过去。您需要检查此项，如果需要，请添加一天。