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异步操作AsyncTask（二）从网络下载图片（带下载进度数据）
package com.example.asyntaskproject;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends Activity {
private ImageView imageView;
private Button button;
//图片的网络地址
private String image_path = "http://pic4.nipic.com/20090828/2366808_092035042961_2.jpg";
private ProgressDialog dialog ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageView = (ImageView) findViewById(R.id.imageView1);
button = (Button) findViewById(R.id.button1);
dialog = new ProgressDialog(this);
dialog.setTitle("提示");
dialog.setMessage("正在下载，请稍后..");
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setCancelable(false);
//不让屏幕失去焦点，即点其他的地方的时候进度条不消失
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
new MyTask().execute(image_path);
}
});
}
public class MyTask extends AsyncTask<String, Integer, Bitmap>{
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
dialog.show();
}
@Override
protected void onProgressUpdate(Integer... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
dialog.setProgress(values[0]);
}
@Override
protected Bitmap doInBackground(String... params) {
// TODO Auto-generated method stub
Bitmap bitmap = null;
//声明一个内存流，用于将他图片读取放到内存缓冲区中
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
InputStream inputStream = null;
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(params[0]);
HttpResponse httpResponse;
try {
httpResponse = httpClient.execute(httpGet);
if(httpResponse.getStatusLine().getStatusCode() == 200){
inputStream = httpResponse.getEntity().getContent();
long file_length = httpResponse.getEntity().getContentLength();
int len = 0;
byte[] data = http://www.mamicode.com/new byte[1024];>
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异步操作AsyncTask（二）从网络下载图片（带下载进度数据）
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