Java ANDROID:将PreviewCallback图像从字节数组保存为.jpg会导致文件损坏
我一直在扩充QR扫描库Zxing,以便扫描后立即保存照片。有人建议我在PreviewCallback.java中的onPreviewFrame方法中这样做,如下所示:Java ANDROID:将PreviewCallback图像从字节数组保存为.jpg会导致文件损坏,java,android,save,photo,zxing,Java,Android,Save,Photo,Zxing,我一直在扩充QR扫描库Zxing,以便扫描后立即保存照片。有人建议我在PreviewCallback.java中的onPreviewFrame方法中这样做,如下所示: public void onPreviewFrame(byte[] data, Camera camera) { Point cameraResolution = configManager.getCameraResolution(); Handler thePreviewHandler = previewHandler; Y
public void onPreviewFrame(byte[] data, Camera camera) {
Point cameraResolution = configManager.getCameraResolution();
Handler thePreviewHandler = previewHandler;
YuvImage im = new YuvImage(data, ImageFormat.NV21, 1200,
800, null);
Rect r = new Rect(0, 0, 1200, 800);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
im.compressToJpeg(r, 50, baos);
try {
FileOutputStream output = new FileOutputStream("/sdcard/test_jpg.jpg");
output.write(baos.toByteArray());
output.flush();
output.close();
System.out.println("Attempting to save file");
System.out.println(data);
} catch (FileNotFoundException e) {
System.out.println("Saving to file failed");
} catch (IOException e) {
System.out.println("Saving to file failed");
}
if (cameraResolution != null && thePreviewHandler != null) {
Message message = thePreviewHandler.obtainMessage(previewMessage, cameraResolution.x,
cameraResolution.y, data);
message.sendToTarget();
previewHandler = null;
} else {
Log.d(TAG, "Got preview callback, but no handler or resolution available");
}}
运行此代码的结果是set file目录中的映像损坏。我相信这是因为代码每帧都在运行。如果允许保存完整图像,是否有方法将此限制为每秒左右,或者是否有方法使图像仅在完成扫描后保存
我有一个不太好的工作选择,我可以成功地保存扫描时显示的黑白图像;当然,颜色是最好的选择
更新:代码更改为(理论上)适应任何设备上的相机分辨率。图像仍然损坏
public void onPreviewFrame(byte[] data, Camera camera) {
Point cameraResolution = configManager.getCameraResolution();
Handler thePreviewHandler = previewHandler;
android.hardware.Camera.Parameters parameters = camera.getParameters();
android.hardware.Camera.Size size = parameters.getPictureSize();
int height = size.height;
int width = size.width;
YuvImage im = new YuvImage(data, ImageFormat.NV21, width,
height, null);
Rect r = new Rect(0, 0, width, height);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
im.compressToJpeg(r, 50, baos);
try {
FileOutputStream output = new FileOutputStream("/sdcard/test_jpg.jpg");
output.write(baos.toByteArray());
output.flush();
output.close();
System.out.println("Attempting to save file");
System.out.println(data);
} catch (FileNotFoundException e) {
System.out.println("Saving to file failed");
} catch (IOException e) {
System.out.println("Saving to file failed");
}
if (cameraResolution != null && thePreviewHandler != null) {
Message message = thePreviewHandler.obtainMessage(previewMessage, cameraResolution.x,
cameraResolution.y, data);
message.sendToTarget();
previewHandler = null;
} else {
Log.d(TAG, "Got preview callback, but no handler or resolution available");
}}
检查宽度和高度变量是否正确设置为Nexus 7的相机宽度和高度1280x960。我相信问题来自于试图在每一帧保存图像,因为“试图保存到文件”在logcat中出现得有点快;一秒钟几次。还值得注意的是,保存的损坏图像为方形(ish)
提前谢谢。1200 x 800?你确定这是你的预览尺寸吗?检查您的参数。可能是1280 x 720是的,是摄像头,检查您的摄像头预览尺寸我如何找到任何设备的摄像头高度和宽度?我已经通过Camera.GetParameters看到了这一点,但我很难找到合适的示例代码。更新后的示例代码应能适应任何相机大小,图像仍然会损坏。您应该使用getPreviewSize()而不是getPictureSize(),我想它们是不同的。尝试一下谢谢你,现在可以成功了,但是我没有办法在扫描时只保存一张照片。我将提出一个新问题来帮助解决这个问题。再次感谢。