添加 displayNotification() 后，Android 应用程序不断崩溃

Question

so the problem is following - My react-native android app keeps crashing, when I try to open it. This started after adding CreateNotificationChannel() and SendNotification() functions. Would like to get some help or tips about my problem. This is my code. As I figured out, there is something wrong about the intent.

package com.notifikacijas;
import android.util.Log;
import android.widget.Toast;

import android.content.Context;
import android.content.Intent;
import android.app.NotificationManager;
import android.app.NotificationChannel;
import android.app.Notification;
import android.app.PendingIntent;
import com.facebook.react.bridge.ReactContextBaseJavaModule;
import android.os.Build;
import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;
import androidx.core.app.NotificationCompat.Builder;
import com.facebook.react.bridge.ReactApplicationContext;
import android.net.Uri;
public class NotificationService extends ReactContextBaseJavaModule {
  private ReactApplicationContext reactContext;

  public NotificationService(ReactApplicationContext reactContext) {
    super(reactContext);
    Log.i("NotificationService", "NotificationService Constructor");
    this.reactContext = reactContext;
    String CHANNEL_ID = "Kanaals";
    NotificationCompat.Builder builders = new NotificationCompat.Builder(this.reactContext, CHANNEL_ID);
    builders.setContentTitle("Virsraksts");
    builders.setContentText("Teksts");
    // createNotificationChannel();
createNotificationChannel();
displayNotification();

  }

  private void displayNotification() {
  Intent intent = this.reactContext.getPackageManager().getLaunchIntentForPackage("dtg");

  intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);

  Uri uri = intent.getData();

  Log.i("NotificationService", "URI "+uri.toString());
  PendingIntent pendingIntent = PendingIntent.getActivity(this.reactContext, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

  String CHANNEL_ID = "notificationsChannel";
  NotificationCompat.Builder builder = new NotificationCompat.Builder(this.reactContext, CHANNEL_ID);
  // builder.setSmallIcon(17301575);
  builder.setContentTitle("Objektā atrodas darbinieki");
  builder.setContentText("Vai vēlaties izreģistrēt darbiniekus no objekta?");
  builder.setPriority(NotificationCompat.PRIORITY_DEFAULT);
  builder.setContentIntent(pendingIntent);
  // builder.setAutoCancel(false);

  NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this.reactContext);
  notificationManager.notify(123, builder.build());
  }

  private void createNotificationChannel() {
String CHANNEL_ID = "notificationsChannel";
// Create the NotificationChannel, but only on API 26+ because
// the NotificationChannel class is new and not in the support library
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
CharSequence name = new StringBuffer("charsequence");
String description = "normals description";
int importance = NotificationManager.IMPORTANCE_DEFAULT;
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
channel.setDescription(description);
// Register the channel with the system; you can't change the importance
// or other notification behaviors after this
NotificationManager notificationManager = this.reactContext.getSystemService(NotificationManager.class);
notificationManager.createNotificationChannel(channel);
}
}

  @Override
  public String getName() {
    return "NotificationService";
  }
}

react-native: 0.61.5

EDIT:: Error log (logcat)

03-13 10:16:45.420 26359 26359 E AndroidRuntime: FATAL EXCEPTION: main
03-13 10:16:45.420 26359 26359 E AndroidRuntime: Process: com.notifikacijas, PID: 26359
03-13 10:16:45.420 26359 26359 E AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.notifikacijas/com.notifikacijas.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.PackageManager com.facebook.react.bridge.ReactApplicationContext.getPackageManager()' on a null object reference
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3107 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3250 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1947 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.os.Handler.dispatchMessage(Handler.java:106 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.os.Looper.loop(Looper.java:214 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.ActivityThread.main(ActivityThread.java:7032 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at java.lang.reflect.Method.invoke(Native Method)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime: Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.PackageManager com.facebook.react.bridge.ReactApplicationContext.getPackageManager()' on a null object reference
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.notifikacijas.NotificationService.displayNotification(NotificationService.java:34 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.notifikacijas.NotificationService.<init>(NotificationService.java:30 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.notifikacijas.MainApplication$1.getPackages(MainApplication.java:29 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.facebook.react.ReactNativeHost.createReactInstanceManager(ReactNativeHost.java:76 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.facebook.react.ReactNativeHost.getReactInstanceManager(ReactNativeHost.java:38 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.facebook.react.ReactDelegate.loadApp(ReactDelegate.java:103 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.facebook.react.ReactActivityDelegate.loadApp(ReactActivityDelegate.java:88 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.facebook.react.ReactActivityDelegate.onCreate(ReactActivityDelegate.java:83 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at com.facebook.react.ReactActivity.onCreate(ReactActivity.java:44 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at android.app.Activity.performCreate(Activity.java:7327 undefined)
03-13 10:16:45.420 26359 26359 E AndroidRuntime:    at andr

MainApplication.java

package com.notifikacijas;

import android.app.Application;
import android.content.Context;
import com.facebook.react.PackageList;
import com.facebook.react.ReactApplication;
import com.facebook.react.ReactNativeHost;
import com.facebook.react.ReactPackage;
import com.facebook.soloader.SoLoader;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
// import NotificationService.java;


public class MainApplication extends Application implements ReactApplication {

  private final ReactNativeHost mReactNativeHost =
      new ReactNativeHost(this) {
        @Override
        public boolean getUseDeveloperSupport() {
          return BuildConfig.DEBUG;
        }

        @Override
        protected List<ReactPackage> getPackages() {
          @SuppressWarnings("UnnecessaryLocalVariable")
          List<ReactPackage> packages = new PackageList(this).getPackages();
          // Packages that cannot be autolinked yet can be added manually here, for example:
        new NotificationService(null);
         return packages;
        }

        @Override
        protected String getJSMainModuleName() {
          return "index";
        }
      };

  @Override
  public ReactNativeHost getReactNativeHost() {
    return mReactNativeHost;
  }

  @Override
  public void onCreate() {
    super.onCreate();
    SoLoader.init(this, /* native exopackage */ false);
    initializeFlipper(this); // Remove this line if you don't want Flipper enabled
  }

  /**
   * Loads Flipper in React Native templates.
   *
   * @param context
   */
  private static void initializeFlipper(Context context) {
    if (BuildConfig.DEBUG) {
      try {
        /*
         We use reflection here to pick up the class that initializes Flipper,
        since Flipper library is not available in release mode
        */
        Class<?> aClass = Class.forName("com.facebook.flipper.ReactNativeFlipper");
        aClass.getMethod("initializeFlipper", Context.class).invoke(null, context);
      } catch (ClassNotFoundException e) {
        e.printStackTrace();
      } catch (NoSuchMethodException e) {
        e.printStackTrace();
      } catch (IllegalAccessException e) {
        e.printStackTrace();
      } catch (InvocationTargetException e) {
        e.printStackTrace();
      }
    }
  }
}

Answer 1

I think reactContext has null value thats why it is unable to get Package Manager. try checking that and assign proper object in reactContext.

Hope this will help you.