從活動的Java類npt調用Android通知

Question

如何從Java類啟動通知？ 我從一個活動啟動了通知，但是當我嘗試從一個Java類開始進行通知時，由於它需要一個上下文（這是指我的類上下文）而無法正常工作，這是從一個活動中啟動通知的函數代碼：

 public  void sendNotification(){
    NotificationCompat.Builder mBuilder =  new NotificationCompat.Builder(this)
                        .setSmallIcon(R.mipmap.ic_camera)
                        .setContentTitle("Someone on your door")
                        .setContentText("Open the camera to see!");

    // Creates an explicit intent for an Activity in your app
        Intent resultIntent = new Intent(this, CameraActivity.class);

// The stack builder object will contain an artificial back stack for the
// started Activity.
// This ensures that navigating backward from the Activity leads out of
// your application to the Home screen.
        TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
// Adds the back stack for the Intent (but not the Intent itself)
        stackBuilder.addParentStack(CameraActivity.class);
// Adds the Intent that starts the Activity to the top of the stack
        stackBuilder.addNextIntent(resultIntent);
        PendingIntent resultPendingIntent =
                stackBuilder.getPendingIntent(
                        0,
                        PendingIntent.FLAG_UPDATE_CURRENT
                );
        mBuilder.setContentIntent(resultPendingIntent);
        NotificationManager mNotificationManager = (NotificationManager)      this.getSystemService(Context.NOTIFICATION_SERVICE);
    // mId allows you to update the notification later on.
        mNotificationManager.notify(CAMERA_NOTIFICATION, mBuilder.build());

    }

在此先感謝您的幫助

Answer 1

為Java類創建一個以Context作為參數的參數化構造函數，並從您的活動中調用它。 您如何從活動中調用Java類。 您可能通過使其對象n調用默認構造函數來調用Java類，我猜是這樣的：

錯誤道

JavaClass obj = new JavaClass();

正確的路

`JavaClass obj = new JavaClass(MainActivity.this); // MainActivity.this is` context

Answer 2

您需要在類中使用上下文 。 在下面的代碼中，我將Context發送到Classes構造函數：

public class SendNotification
    {
        Context context;

        public SendNotification(Context context)
        {
            this.context = context;
        }

         public  void sendNotification()
        {
            NotificationCompat.Builder mBuilder =  new NotificationCompat.Builder(context)
                                .setSmallIcon(R.mipmap.ic_camera)
                                .setContentTitle("Someone on your door")
                                .setContentText("Open the camera to see!");

            // Creates an explicit intent for an Activity in your app
                Intent resultIntent = new Intent(context, CameraActivity.class);

        // The stack builder object will contain an artificial back stack for the
        // started Activity.
        // This ensures that navigating backward from the Activity leads out of
        // your application to the Home screen.
                TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
        // Adds the back stack for the Intent (but not the Intent itself)
                stackBuilder.addParentStack(CameraActivity.class);
        // Adds the Intent that starts the Activity to the top of the stack
                stackBuilder.addNextIntent(resultIntent);
                PendingIntent resultPendingIntent =
                        stackBuilder.getPendingIntent(
                                0,
                                PendingIntent.FLAG_UPDATE_CURRENT
                        );
                mBuilder.setContentIntent(resultPendingIntent);
                NotificationManager mNotificationManager = (NotificationManager)      context.getSystemService(Context.NOTIFICATION_SERVICE);
            // mId allows you to update the notification later on.
                mNotificationManager.notify(CAMERA_NOTIFICATION, mBuilder.build());

        }
    }

現在，您可以從您的活動中創建一個對象，並像下面這樣調用sendNotification方法：

SendNotification sendNotification = new SendNotification(this); 
sendNotification.sendNotification();