Looper物件之角色(Demo 4)

这个例子主要演示了主,子线程之间的信息交互 

package com.example.Looper_04;

import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

public class Looper_04 extends Activity implements OnClickListener {
    private final int WC = LinearLayout.LayoutParams.WRAP_CONTENT;
    private final int FP = LinearLayout.LayoutParams.FILL_PARENT;
    public TextView tv;
    private myThread t;
    private Button btn, btn2;
    private Handler h;
    private Context ctx;

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        ctx = this;
        LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        btn = new Button(this);
        btn.setId(101);
        btn.setBackgroundResource(R.drawable.icon);
        btn.setText("test looper");
        btn.setOnClickListener(this);
        LinearLayout.LayoutParams param = new LinearLayout.LayoutParams(100, 50);
        param.topMargin = 10;
        layout.addView(btn, param);
        btn2 = new Button(this);
        btn2.setId(102);
        btn2.setBackgroundResource(R.drawable.icon);
        btn2.setText("exit");
        btn2.setOnClickListener(this);
        layout.addView(btn2, param);
        tv = new TextView(this);
        tv.setTextColor(Color.WHITE);
        tv.setText("");
        LinearLayout.LayoutParams param2 = new LinearLayout.LayoutParams(FP, WC);
        param2.topMargin = 10;
        layout.addView(tv, param2);
        setContentView(layout);
        // 这里执行了子线程
        t = new myThread();
        t.start();
    }

    public void onClick(View v) {
        switch (v.getId()) {
        case 101:
            String obj = "mainThread";
            Message m = h.obtainMessage(1, 1, 1, obj);
            // 发送的消息由子线程的handler来进行处理
            h.sendMessage(m);
            break;
        case 102:
            h.getLooper().quit();
            finish();
            break;
        }
    }

    // ------------------------------------------------
    public class EventHandler extends Handler {
        public EventHandler(Looper looper) {
            super(looper);
        }

        @Override
        public void handleMessage(Message msg) {
            ((Activity) ctx).setTitle((String) msg.obj);
        }
    }

    // ------------------------------------------------
    class myThread extends Thread {
        public void run() {
            // 初始化当前子线程的Looper物件之管理对象
            Looper.prepare();
            h = new Handler() {
                public void handleMessage(Message msg) {
                    //又建立了主线程的handler对象
                    EventHandler ha = new EventHandler(Looper.getMainLooper());
                    String obj = (String) msg.obj + ", myThread";
                    Message m = ha.obtainMessage(1, 1, 1, obj);
                    ha.sendMessage(m);
                }
            };
            Looper.loop();
        }
    }
}

• Looper_4.rar (26.5 KB)
• 下载次数: 5