Cách refresh Activity khi IntentService hoàn thành trong Android

Giới thiệu

Ví dụ này minh họa cách cập nhật UI Activity khi IntentService hoàn thành công việc, sử dụng LocalBroadcastManager để giao tiếp an toàn trong cùng process.

Bước 1: Tạo dự án mới

Android Studio → File → New Project.

Bước 2: Giao diện (res/layout/activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:app="https://schemas.android.com/apk/res-auto"
    xmlns:tools="https://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Khởi động Service"
        android:textSize="25sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

Bước 3: MainActivity với BroadcastReceiver (src/MainActivity.java)

package com.example.andy.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    TextView text;
    BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String value = intent.getStringExtra("someName");
            text.setText(value); // Cập nhật UI trên Main Thread
        }
    };

    @Override
    protected void onStart() {
        super.onStart();
        IntentFilter filter = new IntentFilter();
        filter.addAction("com.example.andy.myapplication");
        LocalBroadcastManager.getInstance(this).registerReceiver(broadcastReceiver, filter);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        text = findViewById(R.id.text);
        text.setOnClickListener(v -> startService(new Intent(MainActivity.this, RefreshService.class)));
    }

    @Override
    protected void onStop() {
        super.onStop();
        LocalBroadcastManager.getInstance(this).unregisterReceiver(broadcastReceiver);
    }
}

Bước 4: IntentService gửi broadcast (RefreshService.java)

package com.example.andy.myapplication;

import android.app.IntentService;
import android.content.Intent;
import android.os.IBinder;
import android.support.v4.content.LocalBroadcastManager;

public class RefreshService extends IntentService {
    public static volatile boolean shouldStop = false;

    public RefreshService() {
        super(RefreshService.class.getSimpleName());
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Intent resultIntent = new Intent("com.example.andy.myapplication");
        resultIntent.putExtra("someName", "Tutorialspoint.com");
        LocalBroadcastManager.getInstance(this).sendBroadcast(resultIntent);

        if (shouldStop) {
            stopSelf();
            return;
        }
    }
}

Bước 5: Manifest

<service android:name=".RefreshService"/>

Giải thích LocalBroadcastManager

• Giao tiếp trong cùng process (an toàn, hiệu năng cao, không cần permission)
• registerReceiver trong onStart(), unregisterReceiver trong onStop() tránh leak
• Action string phải khớp giữa sender và receiver

Chạy ứng dụng

Chạy app → Nhấn "Khởi động Service" → Service chạy xong → TextView cập nhật thành "Tutorialspoint.com".