Bitmap.compress总是返回null
问题描述:
我正在从我的服务器上下载请求的图片,下载后这张图片成功显示,但是当我尝试在SD卡上存储相同的图片时,它返回null。 这是我下载的图像并保存它。我我得到空在通话过程中bitmap.compress(代码)Bitmap.compress总是返回null
void saveImage() {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/saved_images");
myDir.mkdirs();
String fname = "Image.png";
File file = new File (myDir, fname);
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
message_bitmap.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
//write the bytes in file
FileOutputStream fo;
try {
fo = new FileOutputStream(file);
fo.write(bytes.toByteArray());
fo.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
/*if (file.exists()) file.delete();
try {
FileOutputStream out = new FileOutputStream(file);
message_bitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}*/
}
static public Bitmap downloadBitmap(String url) {
final DefaultHttpClient client = new DefaultHttpClient();
final HttpGet getRequest = new HttpGet(url);
try {
HttpResponse response = client.execute(getRequest);
final int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w("ImageDownloader", "Error " + statusCode + " while retrieving bitmap from " + url);
return null;
}
final HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inputStream = null;
try {
inputStream = entity.getContent();
final Bitmap bitmap = BitmapFactory.decodeStream(new FlushedInputStream(inputStream));
return bitmap;
} finally {
if (inputStream != null) {
inputStream.close();
}
entity.consumeContent();
}
}
} catch (Exception e) {
// Could provide a more explicit error message for IOException or IllegalStateException
getRequest.abort();
Log.w("ImageDownloader", "Error while retrieving bitmap from " + url + e.toString());
} finally {
if (client != null) {
}
}
return null;
}
答
我觉得你已经很接近那里。如何相似,其下载下面有什么东西保存的图像:
try {
img_value = new URL("your_url");
} catch (MalformedURLException e) {
e.printStackTrace();
}
try {
mIcon1 = BitmapFactory.decodeStream(img_value.openConnection()
.getInputStream());
} catch (IOException e) {
e.printStackTrace();
}
String filename = "your_filename.jpg";
File file = new File(dir, filename);
if (file.exists()) {
try{
file.delete();
}catch(Exception e){
//sdcard plugged in
}
}
try {
FileOutputStream out = new FileOutputStream(file);
mIcon1.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();//will occur if the phone is plugged in
}
Bitmap.compress返回null我总是正如我所说,我休息的代码是完全一样的 – user1918034
你压缩()调用使用ByteOutputStream不是一个FileOutputStream 。你确定你在saveImage()的底部注释掉的那段代码不工作吗?上面的代码对我来说是正确的。 – MarkMan