Handler, AsyncTask用法简单示例

package com.jim.testapp;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;

class MyHandler extends Handler
{
    private Activity mActivity;
    private Button btn;
    public MyHandler(Activity activity) {
        mActivity = activity;
        btn = (Button)activity.findViewById(R.id.button);
    }

    @Override
    public void handleMessage(Message msg) {
        Integer integer = (Integer) msg.obj;
        switch (msg.what) {
            case MainActivity.MSG_ONE:
                btn.setText(integer.toString());
                break;
        }
    }
}

class MyAsyncTask extends AsyncTask<String, Integer, Integer> {

    private MainActivity mActivity;
    private Button btn;

    public MyAsyncTask(MainActivity activity) {
        mActivity = activity;
        btn = (Button)activity.findViewById(R.id.button);
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        btn.setText("Loading start");
    }

    @Override
    protected void onPostExecute(Integer integer) {
        super.onPostExecute(integer);
        btn.setText("Loading finished");
        Log.i(MainActivity.TAG, "Result is " + integer);
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
        btn.setText("Loading " + values[0] + "%");
    }

    @Override
    protected Integer doInBackground(String... params) {
        Log.i(MainActivity.TAG, params[0]);
        for (int i = 1; i <= 10; i++) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
            publishProgress(i*10);
        }
        return 0;
    }
}

public class MainActivity extends AppCompatActivity {

    public static final String TAG = "jimtest";
    public static final int MSG_ONE = 1;
    public static final int MSG_TWO = 2;

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

        //MyAsyncTask task = new MyAsyncTask(this);
        //task.execute("i am the param");

        final MyHandler h = new MyHandler(this);

        Runnable r = new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 10; i++) {
                    h.obtainMessage(MSG_ONE, new Integer(i)).sendToTarget();
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                    }
                }

            }
        };

        new Thread(r).start();

    }
}