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
<RelativeLayout 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" ><ImageViewandroid: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"/></RelativeLayout>
另外在AndroidManifest.xml中需要添加以下权限，以便访问网络
<uses-permission android:name="android.permission.INTERNET" />
结束！