localbroadcast-snippet

localbroadcast-snippet.java

public class ExampleActivity extends AppCompatActivity {
    ...
    // Declaration of the broadcast receiver
    private BroadcastReceiver mMessageReceiver = new BroadcastReceiver()     {
        @Override
        public void onReceive(Context context, Intent intent) {
            // Retrieving of the parcelable object
            ComplexObject complexObject = 
                       intent.getParcelableExtra("MyComplexObject");
            textView.setText(complexObject.getMessage());
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        AsyncTask asyncTask = new ExampleTask();
        asyncTask.execute("Hello ! ");
        ...
    }

    @Override
    public void onResume() {
        super.onResume();
        LocalBroadcastManager localBroadcastManager = 
                                 LocalBroadcastManager.getInstance(this);
        // Registering of the broadcast receiver
        localBroadcastManager.registerReceiver(mMessageReceiver, 
new IntentFilter("MyIntentMessage"));
    }

    @Override
    public void onPause() {
        // Unregistering of the broadcast receiver
        localBroadcastManager.unregisterReceiver(mMessageReceiver);
        super.onPause();
    }

    // Declaration of the message object
    // Implementation of the parcelable methods
    class ComplexObject implements Parcelable {

        private String message;
        // Other fields ...

        public ComplexObject(String message) {
            this.message = message;
        }

        public String getMessage() {
            return message;
        }

        protected ComplexObject(Parcel in) {
            message = in.readString();
        }

        public final Creator<ComplexObject> CREATOR = 
         new Creator<ComplexObject>() {
            @Override
            public ComplexObject createFromParcel(Parcel in) {
                return new ComplexObject(in);
            }

            @Override
            public ComplexObject[] newArray(int size) {
                return new ComplexObject[size];
            }
        };

        @Override
        public void writeToParcel(Parcel parcel, int i) {
            parcel.writeString(message);
            // Writting of the other fields...
        }

        @Override
        public int describeContents() {
            return 0;
        }
    }

    class ExampleTask extends AsyncTask<Object, Void, Void>{

        @Override
        protected Void doInBackground(Object... objects) {
            Intent intent = new Intent("MyIntentMessage");
            intent.putExtra("MyComplexObject", 
                                  new ComplexObject((String)strings[0]));
            LocalBroadcastManager.getInstance(getApplicationContext()).
sendBroadcast(intent);

            return null;
        }

    }
}