Bitmap bmp = intent.getExtras().get("data");
int size = bmp.getRowBytes() * bmp.getHeight();
ByteBuffer b = ByteBuffer.allocate(size);
bmp.copyPixelsToBuffer(b);
byte[] bytes = new byte[size];
try {
b.get(bytes, 0, bytes.length);
} catch (BufferUnderflowException e) {
// always happens
}
// do something with byte[]
当我在调用copyPixelsToBuffer后查看缓冲区时，字节都是0…从相机返回的位图是不可变的…但这不重要，因为它正在复制。
这段代码可能有什么问题?
当前回答
为了避免较大文件的OutOfMemory错误，我建议通过将位图分成几个部分并合并它们部分的字节来解决任务。
private byte[] getBitmapBytes(Bitmap bitmap)
{
int chunkNumbers = 10;
int bitmapSize = bitmap.getRowBytes() * bitmap.getHeight();
byte[] imageBytes = new byte[bitmapSize];
int rows, cols;
int chunkHeight, chunkWidth;
rows = cols = (int) Math.sqrt(chunkNumbers);
chunkHeight = bitmap.getHeight() / rows;
chunkWidth = bitmap.getWidth() / cols;
int yCoord = 0;
int bitmapsSizes = 0;
for (int x = 0; x < rows; x++)
{
int xCoord = 0;
for (int y = 0; y < cols; y++)
{
Bitmap bitmapChunk = Bitmap.createBitmap(bitmap, xCoord, yCoord, chunkWidth, chunkHeight);
byte[] bitmapArray = getBytesFromBitmapChunk(bitmapChunk);
System.arraycopy(bitmapArray, 0, imageBytes, bitmapsSizes, bitmapArray.length);
bitmapsSizes = bitmapsSizes + bitmapArray.length;
xCoord += chunkWidth;
bitmapChunk.recycle();
bitmapChunk = null;
}
yCoord += chunkHeight;
}
return imageBytes;
}
private byte[] getBytesFromBitmapChunk(Bitmap bitmap)
{
int bitmapSize = bitmap.getRowBytes() * bitmap.getHeight();
ByteBuffer byteBuffer = ByteBuffer.allocate(bitmapSize);
bitmap.copyPixelsToBuffer(byteBuffer);
byteBuffer.rewind();
return byteBuffer.array();
}
其他回答
尝试转换字符串-位图或位图-字符串
/**
* @param bitmap
* @return converting bitmap and return a string
*/
public static String BitMapToString(Bitmap bitmap){
ByteArrayOutputStream baos=new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG,100, baos);
byte [] b=baos.toByteArray();
String temp=Base64.encodeToString(b, Base64.DEFAULT);
return temp;
}
/**
* @param encodedString
* @return bitmap (from given string)
*/
public static Bitmap StringToBitMap(String encodedString){
try{
byte [] encodeByte=Base64.decode(encodedString,Base64.DEFAULT);
Bitmap bitmap= BitmapFactory.decodeByteArray(encodeByte, 0, encodeByte.length);
return bitmap;
}catch(Exception e){
e.getMessage();
return null;
}
}
压缩格式太慢…
ByteBuffer试试。
※※※位图到字节※※※
width = bitmap.getWidth();
height = bitmap.getHeight();
int size = bitmap.getRowBytes() * bitmap.getHeight();
ByteBuffer byteBuffer = ByteBuffer.allocate(size);
bitmap.copyPixelsToBuffer(byteBuffer);
byteArray = byteBuffer.array();
※※※真佩服to bitmap※※※
Bitmap.Config configBmp = Bitmap.Config.valueOf(bitmap.getConfig().name());
Bitmap bitmap_tmp = Bitmap.createBitmap(width, height, configBmp);
ByteBuffer buffer = ByteBuffer.wrap(byteArray);
bitmap_tmp.copyPixelsFromBuffer(buffer);
您的字节数组太小。每个像素占用4个字节，而不是1个字节，所以将你的大小乘以4，这样数组就足够大了。
使用下面的函数将位图编码为字节[]，反之亦然
public static String encodeTobase64(Bitmap image) {
Bitmap immagex = image;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
immagex.compress(Bitmap.CompressFormat.PNG, 90, baos);
byte[] b = baos.toByteArray();
String imageEncoded = Base64.encodeToString(b, Base64.DEFAULT);
return imageEncoded;
}
public static Bitmap decodeBase64(String input) {
byte[] decodedByte = Base64.decode(input, 0);
return BitmapFactory.decodeByteArray(decodedByte, 0, decodedByte.length);
}
试试这样做:
Bitmap bmp = intent.getExtras().get("data");
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();
bmp.recycle();
