Question

我想在状态栏中显示其他应用程序发布的通知。所以我做了一个按钮。单击该按钮将调用executeButtonClick()方法。 我的代码：

public void executeButtonClick(View view) {
    NLService nlService = new NLService();
    if(nlService.getActiveNotifications()!=null) {
        Toast.makeText(MainActivity.this,"InsideIf",Toast.LENGTH_SHORT).show();
        for (StatusBarNotification sbn : nlService.getActiveNotifications()) {
            String temp = "Package Name: " + sbn.getPackageName() +
                    "\n" + "Title: " + sbn.getNotification().extras.getString("android.title") + "\n" +
                    "Text: " + sbn.getNotification().extras.getCharSequence("android.text");
            String newText = textView.getText().toString() + temp;
            textView.setText(newText);

        }
    }
}

但是未显示通知，并且我得到了空指针异常：

"Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference"

在以下行中：activity.executeButtonClick(com.example.asus.notificationtest.MainActivity.textView);

下面提到的onNotificationPosted()方法的

：

public class NLService extends NotificationListenerService {

Context context;

@Override
public void onCreate() {
    super.onCreate();
    context = getApplicationContext();
}

@Override
public void onNotificationPosted(StatusBarNotification sbn) {
    if(MainActivity.textView != null)
        activity.executeButtonClick(com.example.asus.notificationtest.MainActivity.textView);
    //Toast.makeText(this,"Post from: "+sbn.getPackageName(),Toast.LENGTH_SHORT).show();
}

@Override
public void onNotificationRemoved(StatusBarNotification sbn) {
    //Toast.makeText(this,"Post from: "+sbn.getPackageName(),Toast.LENGTH_SHORT).show();
}

Answer 1

要使Notification侦听器服务正常运行，有许多步骤？是否完全检测到通知？

步骤： 1）在清单中请求权限（例如）：

  <service android:name=".TheNotificationListener"
    android:label="NotifiationListener"
    android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE">
    <intent-filter>
        <action android:name="android.service.notification.NotificationListenerService" />
    </intent-filter>

2）向用户请求运行时权限：

   private void assessPermissions() {
    if(isPermissionRequired()){
        requestNotificationPermission();
    }else{
        startBackground();
    }
}

public boolean isPermissionRequired() {
    ComponentName cn = new ComponentName(this, TheNotificationListener.class);
    String flat = Settings.Secure.getString(this.getContentResolver(), "enabled_notification_listeners");
    final boolean enabled = flat != null && flat.contains(cn.flattenToString());
    return !enabled;
}

private void requestNotificationPermission() {
    Intent intent=new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
    startActivityForResult(intent, 101);
}

提示：确保从通知侦听器服务中删除绑定操作！我花了一天的时间才弄清楚我不应该在那儿放那个代码。

在Android中实现NotificationListenerService

1 个答案: