AsyncTask

[java]代码库

package com.example.day_07asynctask;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.concurrent.ExecutionException;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;

public class MainActivity extends Activity {

    private ImageView imageview;
	private ProgressBar progressBar;
	@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageview = (ImageView) findViewById(R.id.imageview);
        progressBar = (ProgressBar) findViewById(R.id.progressBar);
    }
    public void button(View v){
    	AsyncTask<URL, Integer, Bitmap> asyncTask=new AsyncTask<URL, Integer, Bitmap>() {
			private Bitmap bitmap;
			@Override
			protected void onPreExecute() {
				// TODO Auto-generated method stub
				super.onPreExecute();
				progressBar.setVisibility(View.VISIBLE);
			}
			@Override
			protected Bitmap doInBackground(URL... params) {
				try {
					String path="http://zxpic.gtimg.com/infonew/0/wechat_pics_-8590809.jpg/640";
					URL url=new URL(path);
					HttpURLConnection openConnection = (HttpURLConnection) url.openConnection();
					openConnection.setConnectTimeout(5000);
					openConnection.setRequestMethod("GET");
					openConnection.setReadTimeout(5000);
					openConnection.connect();
					if(200==openConnection.getResponseCode()){
						InputStream inputStream = openConnection.getInputStream();
						bitmap = BitmapFactory.decodeStream(inputStream);
						//返回
						return bitmap;
					}
				} catch (MalformedURLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return null;
			}
			@Override
			protected void onPostExecute(Bitmap result) {
				// TODO Auto-generated method stub
				super.onPostExecute(result);
				imageview.setImageBitmap(bitmap);
				progressBar.setVisibility(View.GONE);
			}
		};
		asyncTask.execute();
    	
    }
    


   
}