我们的应用或多或少都会从网络获取图片数据然后进行显示，下面就将实现一个这样的例子，获取网络中的图片！

首先：我们来看一下效果图

界面中有三个控件，一个EditText，一个Button，一个ImageView

1、下面是具体布局文件

<EditText
　　android:id="@+id/picturepagh"
　　android:layout_width="fill_parent"
　　android:layout_height="wrap_content"
　　android:text="@string/hello_world" />

<Button
　　android:id="@+id/btn"
　　android:layout_width="fill_parent"
　　android:layout_height="wrap_content"
　　android:text="查看" />

<ImageButton
　　android:id="@+id/imageView"
　　android:layout_width="fill_parent"
　　android:layout_height="200px" />

2、在MainActivity中进行图片图示代码编写

public class MainActivity extends Activity {
private Button btn;
private EditText path;
private ImageView imgview;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.btn);
path = (EditText) findViewById(R.id.picturepagh);
imgview = (ImageView) findViewById(R.id.imageView);

btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.i("CLICK", ((Button) v).getText().toString());
new Thread(runa).start();
}
});
}

public void setView() {
String picturepath = path.getText().toString();
byte[] data = null;
try {
data = ImageService.getImage(picturepath);
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);// BitmapFactory：图片工厂！
Looper.prepare();// 必须调用此方法，要不然会报错
Message msg = new Message();
msg.what = 0;
msg.obj = bitmap;
handler.sendMessage(msg);
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "获取图片错误", 1).show();
}
}

private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == 0) {
updateImageView((Bitmap) msg.obj);
}
}

};

private Runnable runa = new Runnable() {
@Override
public void run() {
setView();
}
};

private void updateImageView(Bitmap bm) {
imgview.setImageBitmap(bm);
}
}

3、添加一个ImageService图片服务类，里面包含一个获取网络数据的方法；

public class ImageService {

// 获取网络图片的数据
public static byte[] getImage(String picturepath) throws Exception {
URL url = new URL(picturepath);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();// 基于http协议的连接对象
conn.setConnectTimeout(10);// 10秒；
conn.setRequestMethod("GET");// 大写
if (conn.getResponseCode() == 200) {
InputStream ins = conn.getInputStream();
return StreamTool.read(ins);
}
return null;
}
}

4、添加一个流处理工作类StreamTool

public class StreamTool {

public static byte[] read(InputStream ins) throws Exception {
ByteArrayOutputStream outstream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length = 0;
while ((length = ins.read(buffer)) > -1) {
outstream.write(buffer, 0, length);
}
outstream.close();
return outstream.toByteArray();
}
}

5、大功告成？NO，还要添加网络访问权限： <uses-permission android:name="android.permission.INTERNET" />

OK，运行程序！