AsyncTask下载网络图片的简单应用

使用AsyncTask加载图片

最新推荐文章于 2025-09-05 16:34:31 发布

转载最新推荐文章于 2025-09-05 16:34:31 发布 · 82 阅读

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原文链接：http://www.cnblogs.com/liupengcheng/p/5028795.html

文章标签：

#移动开发 #java

本文介绍了一个简单的Android应用示例，该应用通过AsyncTask后台任务从网络下载并显示一张图片。示例包括了完整的源代码，涉及Activity配置、进度条显示、图片加载等步骤。

1、imageTest

package lpc.com.asynctaskdemo;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
/**
* Created by Administrator on 2015/12/8.
*/
public class ImageTest extends Activity {
private ImageView mImageView;
private ProgressBar mProgressBar;
private String URL = "http://cdnq.duitang.com/uploads/item/201409/14/20140914172442_sjXYv.jpeg";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.image);
mImageView = (ImageView) findViewById(R.id.image);
mProgressBar = (ProgressBar) findViewById(R.id.progress);
new MyAsycTask().execute(URL);
}
class MyAsycTask extends AsyncTask<String,Void,Bitmap>{
@Override
protected void onPreExecute() {
super.onPreExecute();
mProgressBar.setVisibility(View.VISIBLE);
}
@Override
protected void onPostExecute(Bitmap bitmap) {
super.onPostExecute(bitmap);
mProgressBar.setVisibility(View.GONE);
mImageView.setImageBitmap(bitmap);
}
@Override
protected Bitmap doInBackground(String... params) {
String url = params[0];
Bitmap bitmap = null;
URLConnection connection;
InputStream is;
try {
connection = new URL(url).openConnection();
is = connection.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
bitmap = BitmapFactory.decodeStream(bis);
is.close();
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
return bitmap;
}
}
}