// ===============================================
// 文件：MainActivity.java
// 位置：app/src/main/java/com/example/timerefresh/MainActivity.java
// 功能：演示多種實現界面定時刷新的方法
// ===============================================
 
package com.example.timerefresh;
 
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Message;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
 
public class MainActivity extends AppCompatActivity {
 
    private TextView tvRefresh;
    private int counter = 0; // 記錄刷新次數
 
    // 方式1：Handler + Runnable
    private Handler handler = new Handler(Looper.getMainLooper());
    private Runnable refreshRunnable = new Runnable() {
        @Override
        public void run() {
            updateUI("Handler + Runnable 定時刷新：" + (++counter));
            handler.postDelayed(this, 2000); // 每隔2秒執(zhí)行一次
        }
    };
 
    // 方式2：Timer + TimerTask
    private Timer timer;
    private TimerTask timerTask;
 
    // 方式3：ScheduledExecutorService
    private ScheduledExecutorService scheduler;
 
    // 方式4：HandlerThread
    private HandlerThread handlerThread;
    private Handler backgroundHandler;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tvRefresh = findViewById(R.id.tvRefresh);
 
        // 啟動方式1
        handler.postDelayed(refreshRunnable, 2000);
 
        // 啟動方式2
        startTimerTask();
 
        // 啟動方式3
        startScheduler();
 
        // 啟動方式4
        startHandlerThread();
    }
 
    // 更新界面的方法（必須在主線程）
    private void updateUI(String text) {
        runOnUiThread(() -> tvRefresh.setText(text));
    }
 
    // 啟動 Timer 定時任務
    private void startTimerTask() {
        timer = new Timer();
        timerTask = new TimerTask() {
            @Override
            public void run() {
                updateUI("Timer 定時刷新：" + (++counter));
            }
        };
        timer.schedule(timerTask, 2000, 2000); // 延遲2秒后，每隔2秒執(zhí)行一次
    }
 
    // 啟動 ScheduledExecutorService 定時任務
    private void startScheduler() {
        scheduler = Executors.newScheduledThreadPool(1);
        scheduler.scheduleAtFixedRate(() -> {
            updateUI("ScheduledExecutorService 定時刷新：" + (++counter));
        }, 2, 2, TimeUnit.SECONDS);
    }
 
    // 啟動 HandlerThread 定時任務
    private void startHandlerThread() {
        handlerThread = new HandlerThread("RefreshThread");
        handlerThread.start();
        backgroundHandler = new Handler(handlerThread.getLooper()) {
            @Override
            public void handleMessage(Message msg) {
                updateUI("HandlerThread 定時刷新：" + (++counter));
                backgroundHandler.sendEmptyMessageDelayed(0, 2000);
            }
        };
        backgroundHandler.sendEmptyMessageDelayed(0, 2000);
    }
 
    @Override
    protected void onDestroy() {
        super.onDestroy();
        // 釋放 Handler
        handler.removeCallbacks(refreshRunnable);
 
        // 釋放 Timer
        if (timer != null) {
            timer.cancel();
        }
 
        // 釋放 ScheduledExecutorService
        if (scheduler != null) {
            scheduler.shutdown();
        }
 
        // 釋放 HandlerThread
        if (handlerThread != null) {
            handlerThread.quit();
        }
    }
}
 
 
// ===============================================
// 文件：activity_main.xml
// 位置：app/src/main/res/layout/activity_main.xml
// 功能：簡單布局，包含一個 TextView 用于展示刷新效果
// ===============================================
 
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:padding="20dp">
 
    <TextView
        android:id="@+id/tvRefresh"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="等待刷新..."
        android:textSize="18sp"
        android:textColor="@android:color/black"/>
</LinearLayout>