我有以下代码 fragment 。标记的行导致 BufferUnderflowException。我阅读了有关异常的文档,但仍然不明白它的含义究竟。我使用 .rewind()
方法,我印象中它可以缓解这个问题。
谁能告诉我错误的主题或原因?
Bitmap cameraBaseSized = BitmapFactory.decodeFile(cameraPath, opts);
Bitmap canvasBlendSized = BitmapFactory.decodeFile(canvasPath, options);
Bitmap result = cameraBaseSized.copy(Config.ARGB_8888, true);
IntBuffer buffBase = IntBuffer.allocate(cameraBaseSized.getWidth()
* cameraBaseSized.getHeight());
cameraBaseSized.copyPixelsToBuffer(buffBase);
buffBase.rewind();
IntBuffer buffBlend = IntBuffer.allocate(canvasBlendSized.getWidth()
* canvasBlendSized.getHeight());
canvasBlendSized.copyPixelsToBuffer(buffBlend);
buffBlend.rewind();
IntBuffer buffOut = IntBuffer.allocate(cameraBaseSized.getWidth()
* cameraBaseSized.getHeight());
buffOut.rewind();
while (buffOut.position() < buffOut.limit()) {
int filterInt = buffBlend.get(); //BUFFERUNDERFLOW EXCEPTION
int srcInt = buffBase.get();
int redValueFilter = Color.red(filterInt);
int greenValueFilter = Color.green(filterInt);
int blueValueFilter = Color.blue(filterInt);
int redValueSrc = Color.red(srcInt);
int greenValueSrc = Color.green(srcInt);
int blueValueSrc = Color.blue(srcInt);
int redValueFinal = multiply(redValueFilter, redValueSrc);
int greenValueFinal = multiply(greenValueFilter, greenValueSrc);
int blueValueFinal = multiply(blueValueFilter, blueValueSrc);
int pixel = Color.argb(255, redValueFinal, greenValueFinal, blueValueFinal);
buffOut.put(pixel);
}
buffOut.rewind();
result.copyPixelsFromBuffer(buffOut);
异常 fragment
11-29 14:41:57.347: E/AndroidRuntime(2166): Caused by: java.nio.BufferUnderflowException
11-29 14:41:57.347: E/AndroidRuntime(2166): at java.nio.IntArrayBuffer.get(IntArrayBuffer.java:55)
我还想补充一点,这只发生在特定设备上,尤其是三星机型。
最佳答案
也许这个测试会有所帮助:
ByteBuffer b = ByteBuffer.allocate(1);
b.get();
b.get();
分配后缓冲区中有 1 个字节,第一个 get() 读取这个字节并且缓冲区达到其限制,第二个 get() 是非法的,没有任何内容可读,所以你得到 BufferUnderflowException。
此代码不会失败:
ByteBuffer b = ByteBuffer.allocate(1);
b.get();
b.rewind();
b.get();
你读取了这个字节,但是它还在缓冲区中,所以你可以倒带它并再次读取这个字节
关于java - 缓冲区下溢?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13633522/