Java DecodeBytarray和copyPixelsToBuffer不工作。SkImageDecoder::工厂返回null
我有一个实现Serializable的类TouchPoint,因为它包含位图,所以我为该类编写了writeObject和readObject:Java DecodeBytarray和copyPixelsToBuffer不工作。SkImageDecoder::工厂返回null,java,android,bitmap,bytearray,serializable,Java,Android,Bitmap,Bytearray,Serializable,我有一个实现Serializable的类TouchPoint,因为它包含位图,所以我为该类编写了writeObject和readObject: private void writeObject(ObjectOutputStream oos) throws IOException { long t1 = System.currentTimeMillis(); oos.defaultWriteObject(); if(_bmp!=null){ int byte
private void writeObject(ObjectOutputStream oos) throws IOException {
long t1 = System.currentTimeMillis();
oos.defaultWriteObject();
if(_bmp!=null){
int bytes = _bmp.getWidth()*_bmp.getHeight()*4;
ByteBuffer buffer = ByteBuffer.allocate(bytes);
_bmp.copyPixelsToBuffer(buffer);
byte[] array = buffer.array();
oos.writeObject(array);
}
Log.v("PaintFX","Elapsed Time: "+(System.currentTimeMillis()-t1));
}
private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException{
ois.defaultReadObject();
byte[] data = (byte[]) ois.readObject();
if(data != null && data.length > 0){
_bmp = BitmapFactory.decodeByteArray(data, 0, data.length);
}
}
问题是,我得到了
SkImageDecoder::工厂返回null
那我该怎么修呢。我知道可能的解决方案是将writeObject()更改为
但这种方法的速度要慢近10倍以上
- copyPixelsToBuffer~14ms用于写入图像
- _bmp.compress~160ms
buffer.array();
所有字节[]数组元素都是:0位图到字节[]:
Bitmap bmp; // your bitmap
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();
使用Bufferedstreams可以获得更好的性能。最后,我找到了一种方法,使它能够工作,同时速度更快。使用此方法时,我遇到两个问题:
private void writeObject(ObjectOutputStream oos) throws IOException {
oos.defaultWriteObject();
if(_bmp!=null){
int bytes = _bmp.getWidth()*_bmp.getHeight()*4;
ByteBuffer buffer = ByteBuffer.allocate(bytes);
_bmp.copyPixelsToBuffer(buffer);
byte[] array = new byte[bytes]; // looks like this is extraneous memory allocation
if (buffer.hasArray()) {
try{
array = buffer.array();
} catch (BufferUnderflowException e) {
e.printStackTrace();
}
}
String configName = _bmp.getConfig().name();
oos.writeObject(array);
oos.writeInt(_bmp.getWidth());
oos.writeInt(_bmp.getHeight());
oos.writeObject(configName);
} else {
oos.writeObject(null);
}
}
private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException{
ois.defaultReadObject();
byte[] data = (byte[]) ois.readObject();
if (data != null) {
int w = ois.readInt();
int h = ois.readInt();
String configName = (String) ois.readObject();
Bitmap.Config configBmp = Bitmap.Config.valueOf(configName);
Bitmap bitmap_tmp = Bitmap.createBitmap(w, h, configBmp);
ByteBuffer buffer = ByteBuffer.wrap(data);
bitmap_tmp.copyPixelsFromBuffer(buffer);
_bmp = bitmap_tmp.copy(configBmp,true);
bitmap_tmp.recycle();
} else {
_bmp = null;
}
}
这对我来说已经足够快了-大约比bmp.compress方式快15倍。希望这有帮助:)您没有收到任何其他错误消息吗?也许,
int bytes=\u bmp.getRowBytes()*\u bmp.getHeight()
可以解决您的问题。不,我没有收到其他消息。这并不能解决问题。然而,我找到了解决这个问题的方法。稍后我会发布一个答案。我已经说过这个方法太慢了,因为它压缩位图需要很多时间。我已经找到了比下面的方法快15倍的方法。它看起来比下面的方法慢得多。我做错什么了吗?
private void writeObject(ObjectOutputStream oos) throws IOException {
oos.defaultWriteObject();
if(_bmp!=null){
int bytes = _bmp.getWidth()*_bmp.getHeight()*4;
ByteBuffer buffer = ByteBuffer.allocate(bytes);
_bmp.copyPixelsToBuffer(buffer);
byte[] array = new byte[bytes]; // looks like this is extraneous memory allocation
if (buffer.hasArray()) {
try{
array = buffer.array();
} catch (BufferUnderflowException e) {
e.printStackTrace();
}
}
String configName = _bmp.getConfig().name();
oos.writeObject(array);
oos.writeInt(_bmp.getWidth());
oos.writeInt(_bmp.getHeight());
oos.writeObject(configName);
} else {
oos.writeObject(null);
}
}
private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException{
ois.defaultReadObject();
byte[] data = (byte[]) ois.readObject();
if (data != null) {
int w = ois.readInt();
int h = ois.readInt();
String configName = (String) ois.readObject();
Bitmap.Config configBmp = Bitmap.Config.valueOf(configName);
Bitmap bitmap_tmp = Bitmap.createBitmap(w, h, configBmp);
ByteBuffer buffer = ByteBuffer.wrap(data);
bitmap_tmp.copyPixelsFromBuffer(buffer);
_bmp = bitmap_tmp.copy(configBmp,true);
bitmap_tmp.recycle();
} else {
_bmp = null;
}
}