Android笔记之Handler

 * 二者比较明显handler速度要快一点
 * 如果异步任务的数据特别庞大，AsyncTask这种线程池结构的优势就体现出来了。

public class MainActivity extends Activity {

    private Button button1, button2;private Dialog dialog;
    private ProgressDialog progressDialog;

    String path = "http://g.hiphotos.baidu.com/album/w%3D2048/sign=d6ae435755e736d158138b08af684dc2/9358d109b3de9c82bff8f4046d81800a18d8439f.jpg";
    //用做处理线程传递的消息handler.sendMessage(message1);
    private Handler handler = new Handler() {
        @Override
        public void handleMessage(android.os.Message msg) {
                             ....

            Bundle bundle = msg.getData();
            String string = bundle.getString("Id");
            if (msg.what == 1) {
                //这里1表示完成
                dialog.dismiss();
            }

        };
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = (ImageView) findViewById(R.id.imageView1);

        dialog = new ProgressDialog(this);
        dialog.setTitle("正在下载...");
        dialog.setCancelable(false);

        progressDialog = new ProgressDialog(this);
        progressDialog.setTitle("标题Title...");
        progressDialog.setMessage("信息Message...");
        // 不会失去焦点
        progressDialog.setCancelable(false);
        // 横向进度条
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(H);
    }

    private View.OnClickListener H = new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            // 等同与于new Thread(new Runnable() {).start();，为了复用性选择新建class
            new Thread(new DownImgThread()).start();
           // 显示对话框
            dialog.show();

        }
    };

    // 内部类，于class之下，与onCreate平齐
    public class DownImgThread implements Runnable {

        @Override
        public void run() {
            // TODO Auto-generated method stub
            // 线程主体，完成网络耗时操作
            // 仅仅只做发送message的操作，更新ui什么的在handleMessage里面
                       ........// 第一种
                    Message message1 = Message.obtain();
                    message1.obj = data;
                    message1.what = 1;
                    // 不sendMessage則不會產生效果
                    handler.sendMessage(message1);
                    // 第二种,绑定handler
                    // Message message2 = Message.obtain(handler);
                    // message2.obj = data;
                    // message2.what = isFinish;
                    // message2.sendToTarget();
                    // //第三种
                    // //第四种
                    // Message message4 = Message.obtain(handler,0,1,2,"hello");
                    // //传递复杂的数据类型
                    // Bundle bundle=new Bundle();
                    // bundle.putString("Id", "007");
                    // message4.setData(bundle);
                    // message4.sendToTarget();
        }

    }

Done !