最近專案中，發現程式的反應實在有點慢，主執行緒中的耗時操作多了點，但沒有時間去改，就想寫個公用類，專門用來處理這些耗時操作，於是寫了個 ThreadUtil,

思路是在util中使用一個單例執行緒池，然後用反射的方法去呼叫需要被呼叫的方法，然後用handler去協調，程式碼並沒優美，只是把想法記錄下來，以後再進行優化。程式碼如下：

ThreadUtil.java

package com.bjj.test_thread_step;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * Created by Administrator on 2016/4/18.
 */
public class ThreadUtil {

    private ExecutorService services;

    public static ThreadUtil thread;

    public static ThreadUtil getInstance(){
        if(thread == null){
            thread = new ThreadUtil();
        }
        return  thread;
    }

    public ThreadUtil(){
        services = Executors.newSingleThreadExecutor();
    }

    public void add(final Method method,final Object _class){
        services.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    method.invoke(_class);
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}
 

用Thread.sleep(10000) 來模擬耗時操作

package com.bjj.test_thread_step;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case 0:{
                    try {
                        ThreadUtil.getInstance().add(MainActivity.this.getClass().getMethod("step1"),MainActivity.this);
                    } catch (NoSuchMethodException e) {
                        e.printStackTrace();
                    }
                    break;
                }
                case 1:{
                    try {
                        ThreadUtil.getInstance().add(MainActivity.this.getClass().getMethod("step2"),MainActivity.this);
                    } catch (NoSuchMethodException e) {
                        e.printStackTrace();
                    }
                    break;
                }
                case 2:{
                    try {
                        ThreadUtil.getInstance().add(MainActivity.this.getClass().getMethod("step3"),MainActivity.this);
                    } catch (NoSuchMethodException e) {
                        e.printStackTrace();
                    }
                    break;
                }
                case 3:{
                    try {
                        ThreadUtil.getInstance().add(MainActivity.this.getClass().getMethod("step4"),MainActivity.this);
                    } catch (NoSuchMethodException e) {
                        e.printStackTrace();
                    }
                    break;
                }
            }
        }
    };

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

        findViewById(R.id.start).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                handler.sendEmptyMessage(0);
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    public void step1(){
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                ((TextView) findViewById(R.id.t1)).setText("這是第一步");
            }
        });
        handler.sendEmptyMessage(1);
    }

    public void step2(){
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                ( (TextView)findViewById(R.id.t2) ).setText("這是第二步");
            }
        });
        handler.sendEmptyMessage(2);
    }

    public void step3(){
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                ( (TextView)findViewById(R.id.t3) ).setText("這是第三步");
            }
        });
        handler.sendEmptyMessage(3);
    }

    public void step4(){
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                ( (TextView)findViewById(R.id.t4) ).setText("這是第四步");
            }
        });
    }
}