关于BitmapFactory.decodeStream(is)方法无法正常解码为Bitmap对象的解决方法

关于BitmapFactory.decodeStream(is)方法无法正常解码为Bitmap对象的解决方法

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</pre>在android sdk 1.6版本API帮助文档中，其中关于BitmapFactory.decodeFactory.decodeStream(InputStream is)的帮助文档是这么说明的：<p></p><p></p><pre name="code" class="html">
Bitmap android.graphics.BitmapFactory.decodeStream(InputStream is)

public static Bitmap decodeStream (InputStream is)
Since: API Level 1
Decode an input stream into a bitmap. <strong>If the input stream is null, or cannot be used to decode a bitmap, the function returns null</strong>. The stream's position will be where ever it was after the encoded data was read.

Parameters
is The input stream that holds the raw data to be decoded into a bitmap.

Returns
The decoded bitmap, or null if the image data could not be decoded.

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public static Bitmap bmpFromURL(URL imageURL){

Bitmap result = null;

try {

HttpURLConnection connection = (HttpURLConnection)imageURL .openConnection();

connection.setDoInput(true);

connection.connect();

InputStream input = connection.getInputStream();

result = BitmapFactory.decodeStream(input);

} catch (IOException e) {

e.printStackTrace();

}

return result;

}

public static Bitmap bmpFromURL(URL imageURL){

Bitmap result = null;

try {

HttpURLConnection connection = (HttpURLConnection)imageURL .openConnection();

connection.setDoInput(true);

connection.connect();

InputStream input = connection.getInputStream();

result = BitmapFactory.decodeStream(input);

} catch (IOException e) {

e.printStackTrace();

}

return result;

}

后来调试发现，result为null，加之查看帮助文档中的黑体字，

所以在所获得的InputStream不为空的情况下，调用BitmapFactory.decodeStream(is)方法，他也有可能无法解码成bitmap,刚开始我怀疑是本身图片地址有问题，或图片自身格式不正确，但通过浏览器查看，图片显示正常，而且，我是保存了几十张图片，但每次都会有个别几张图片无法正常显示，需要重复下载三四次，才可能保存成功。

后来在一篇文章中才发现，原来这是android 1.6版本的一个bug！

有牛人提出的一个解决办法，我试了试，问题解决了

首先在原方法中改一句：

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result = BitmapFactory.decodeStream(new PatchInputStream(input));

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public class PatchInputStream extends FilterInputStream{

protected PatchInputStream(InputStream in) {
super(in);
// TODO Auto-generated constructor stub

}

public long skip(long n)throws IOException{
long m=0l;
while(m<n){
long _m=in.skip(n-m);
if(_m==0l){
break;
}
m+=_m;
}
return m;
}

}

public class PatchInputStream extends FilterInputStream{

protected PatchInputStream(InputStream in) {
super(in);
// TODO Auto-generated constructor stub
}

public long skip(long n)throws IOException{
long m=0l;
while(m<n){
long _m=in.skip(n-m);
if(_m==0l){
break;
}
m+=_m;
}
return m;
}

}

第二种方法：最终用的是这种方法

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InputStream is = httpConn.getInputStream();

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if (is == null){
throw new RuntimeException("stream is null");
}else{
try {
byte[] data=readStream(is);
if(data!=null){
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
}
} catch (Exception e) {
e.printStackTrace();
}

is.close();
}

if (is == null){
throw new RuntimeException("stream is null");
}else{
try {
byte[] data=readStream(is);
if(data!=null){
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
}
} catch (Exception e) {
e.printStackTrace();
}

is.close();
}

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/*
* 得到图片字节流 数组大小
* */
public static byte[] readStream(InputStream inStream) throws Exception{
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = 0;
while( (len=inStream.read(buffer)) != -1){
outStream.write(buffer, 0, len);
}
outStream.close();
inStream.close();
return outStream.toByteArray();
}