Android中显示网络图片

本文参照自：  http://developer.51cto.com/art/201001/180968.htm

在 Android 中，显示网络图片还是比较简单的。当我们开始启动一个任务加载一个View对应的图片时，应该通过 setTag() 把该View的tag设置为图片的URL.当实际取得该图片时，应该检查其对应的URL是否和View的TAG一致，只有一致时才把该图片实际应用于该View.

实例1

InternetImageDemoActivity.java文件

package com . lenovo . robin . test ;

import java . io . IOException ;

import java . io . InputStream ;

import java . net . HttpURLConnection ;

import java . net . MalformedURLException ;

import java . net . URL ;

import android . app . Activity ;

import android . graphics . Bitmap ;

import android . graphics . BitmapFactory ;

import android . os . AsyncTask ;

import android . os . Bundle ;

import android . widget . ImageView ;

public class InternetImageDemoActivity extends Activity {

Bitmap bmImg ;

ImageView imView ;

@Override

public void onCreate ( Bundle savedInstanceState ) {

super . onCreate ( savedInstanceState );

setContentView ( R . layout . internet_image_demo );

imView = ( ImageView ) findViewById ( R . id . imageView1 );

String imageUrl = "http://img6.ph.126.net/hBiG96B8egigBULxUWcOpA==/109212290980771276.jpg" ;

final ImageView imageView = imView ;

imageView . setTag ( imageUrl );

ImageLoadedCallback callback = new ImageLoadedCallback () {

@Override

public void loaded ( Bitmap bitMap , String url ) {

// TODO Auto-generated method stub

if (url.equals(imageView.getTag())) {

imageView.setImageBitmap(bitMap);

}

}

};

new DownloadImageTask ( callback ). execute ( imageUrl );

}

}

class DownloadImageTask extends AsyncTask < String , Integer , Bitmap > {

ImageLoadedCallback callback = null ;

String url = null ;

DownloadImageTask ( ImageLoadedCallback callback ) {

this . callback = callback ;

}

protected Bitmap doInBackground ( String ... urls ) {

URL myFileUrl = null ;

Bitmap bitmap = null ;

url = urls [ 0 ];

try {

myFileUrl = new URL ( url );

} catch ( MalformedURLException e ) {

e . printStackTrace ();

}

HttpURLConnection conn = null ;

InputStream is = null ;

try {

conn = ( HttpURLConnection ) myFileUrl

. openConnection ();

conn . setDoInput ( true );

conn . connect ();

is = conn . getInputStream ();

bitmap = BitmapFactory . decodeStream ( is );

is . close ();

} catch ( IOException e ) {

e . printStackTrace ();

}

finally

{

if ( conn != null )

{

try {

conn . connect ();

} catch ( IOException e ) {

// TODO Auto-generated catch block

e.printStackTrace();

}

conn=null;

}

if(is!=null)

{

try {

is.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

is=null;

}

}

return bitmap;

}

protected void onPostExecute ( Bitmap bitMap ) {

callback . loaded ( bitMap , url );

}

}

interface ImageLoadedCallback {

public void loaded ( Bitmap bitMap , String url );

}

关于 AsyncTask请参照《 AsyncTask简介 》

布局文件internet_image_demo.xml

xmlns:android = "http://schemas.android.com/apk/res/android"

    xmlns:tools = "http://schemas.android.com/tools"

    android:layout_width = "match_parent"

    android:layout_height = "match_parent" >

   

        android:id = "@+id/imageView1"

        android:layout_width = "match_parent"

        android:layout_height = "match_parent"

        android:layout_alignLeft = "@+id/button1"

        android:layout_below = "@+id/textView1"

        android:layout_marginTop = "34dp"

  />

另外在AndroidManifest.xml中需要添加以下权限，以便访问网络

android:name="android.permission.INTERNET" />

结束！