Android图片操作-保存图片到SD卡

/**
* Save Bitmap to a file.保存图片到SD卡。
*
* @param bitmap
* @param file
* @return error message if the saving is failed. null if the saving is
*         successful.
* @throws IOException
*/
public static void saveBitmapToFile(Bitmap bitmap, String _file)
throws IOException {
BufferedOutputStream os = null;
try {
File file = new File(_file);
// String _filePath_file.replace(File.separatorChar +
// file.getName(), "");
int end = _file.lastIndexOf(File.separator);
String _filePath = _file.substring(0, end);
File filePath = new File(_filePath);
if (!filePath.exists()) {
filePath.mkdirs();
}
file.createNewFile();
os = new BufferedOutputStream(new FileOutputStream(file));
bitmap.compress(Bitmap.CompressFormat.PNG, 100, os);
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
Log.e(TAG_ERROR, e.getMessage(), e);
}
}
}
}