// ==============================================
// 文件：MainActivity.java
// 功能：演示五種方式實(shí)現(xiàn)界面定時(shí)刷新（實(shí)時(shí)時(shí)鐘示例）
// 包含布局 XML、Gradle 依賴(lài)一處整合，詳細(xì)注釋
// ==============================================
 
package com.example.timerrefresh;
 
import android.os.*;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
 
// RxJava 依賴(lài)
import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.schedulers.Schedulers;
 
// Kotlin Coroutines & Flow 依賴(lài)（需 Kotlin 支持）
// import kotlinx.coroutines.*
// import kotlinx.coroutines.flow.*
 
// Java 并發(fā)
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.*;
 
public class MainActivity extends AppCompatActivity {
    private TextView tvClock;
    private Button btnStart, btnStop;
 
    // --- 方案 A: Handler + postDelayed ---
    private Handler handler = new Handler(Looper.getMainLooper());
    private Runnable taskA = new Runnable() {
        @Override public void run() {
            updateTime();
            handler.postDelayed(this, 1000);
        }
    };
 
    // --- 方案 B: Timer + Handler ---
    private Timer timerB;
    private TimerTask timerTaskB;
 
    // --- 方案 C: ScheduledExecutorService ---
    private ScheduledExecutorService schedulerC;
    private ScheduledFuture<?> futureC;
 
    // --- 方案 D: RxJava interval ---
    private Disposable disposableD;
 
    // --- 方案 E: Kotlin Coroutines + Flow ---
    // private Job jobE;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);  // 布局整合在注釋下方
 
        tvClock   = findViewById(R.id.tvClock);
        btnStart  = findViewById(R.id.btnStart);
        btnStop   = findViewById(R.id.btnStop);
 
        btnStart.setOnClickListener(v -> {
            // 選擇下面一種，注釋其余
            startA();
            // startB();
            // startC();
            // startD();
            // startE();
        });
        btnStop.setOnClickListener(v -> {
            stopA();
            stopB();
            stopC();
            stopD();
            stopE();
        });
    }
 
    /** 更新時(shí)鐘顯示 */
    private void updateTime() {
        String now = new SimpleDateFormat(
            "HH:mm:ss", Locale.getDefault())
            .format(new Date());
        tvClock.setText(now);
    }
 
    // === 方案 A：Handler + postDelayed ===
    private void startA() {
        handler.post(taskA);
    }
    private void stopA() {
        handler.removeCallbacks(taskA);
    }
 
    // === 方案 B：Timer + Handler ===
    private void startB() {
        timerB = new Timer();
        timerTaskB = new TimerTask() {
            @Override public void run() {
                handler.post(() -> updateTime());
            }
        };
        timerB.scheduleAtFixedRate(timerTaskB, 0, 1000);
    }
    private void stopB() {
        if (timerB != null) {
            timerB.cancel();
            timerB = null;
        }
    }
 
    // === 方案 C：ScheduledExecutorService ===
    private void startC() {
        schedulerC = Executors.newSingleThreadScheduledExecutor();
        futureC = schedulerC.scheduleAtFixedRate(() -> {
            runOnUiThread(this::updateTime);
        }, 0, 1, TimeUnit.SECONDS);
    }
    private void stopC() {
        if (futureC != null) futureC.cancel(true);
        if (schedulerC != null) schedulerC.shutdown();
    }
 
    // === 方案 D：RxJava interval ===
    private void startD() {
        disposableD = Observable.interval(0, 1, TimeUnit.SECONDS)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(x -> updateTime());
    }
    private void stopD() {
        if (disposableD != null && !disposableD.isDisposed()) {
            disposableD.dispose();
        }
    }
 
    // === 方案 E：Kotlin Coroutines + Flow ===
    /*
    private void startE() {
        jobE = CoroutineScope(Dispatchers.Main).launch {
            flow {
                while (true) {
                    emit(Unit)
                    delay(1000)
                }
            }.collect {
                updateTime()
            }
        };
    }
    private void stopE() {
        if (jobE != null && jobE.isActive()) {
            jobE.cancel();
        }
    }
    */
 
    @Override protected void onDestroy() {
        super.onDestroy();
        // 確保停止所有方案
        stopA(); stopB(); stopC(); stopD(); stopE();
    }
}
 
/*
=========================== res/layout/activity_main.xml ===========================
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:gravity="center"
    android:padding="24dp"
    android:layout_width="match_parent" android:layout_height="match_parent">
    <TextView
        android:id="@+id/tvClock"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="--:--:--"
        android:textSize="48sp"
        android:textStyle="bold"/>
    <LinearLayout
        android:orientation="horizontal"
        android:layout_marginTop="32dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <Button
            android:id="@+id/btnStart"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="開(kāi)始刷新"/>
        <Button
            android:id="@+id/btnStop"
            android:layout_marginStart="16dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="停止刷新"/>
    </LinearLayout>
</LinearLayout>
=========================== 布局結(jié)束 ===========================
*/
 
/*
=========================== app/build.gradle 關(guān)鍵依賴(lài) ===========================
dependencies {
    implementation 'androidx.appcompat:appcompat:1.5.1'
    implementation 'io.reactivex.rxjava3:rxjava:3.1.5'
    implementation 'io.reactivex.rxjava3:rxandroid:3.0.0'
    // Kotlin Coroutines & Flow（如需要示例 E）
    // implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4'
    // implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.6.4'
}
=========================== Gradle 結(jié)束 ===========================
*/