android 自定义照相机Camera…

对于一些手机，像HTC，当自定义Camera时，调用Camera.Parameters的parameters.setPreviewSize(width,
height)方法时，如果width和height为奇数情况下，则会出现黑屏现象，解决办法可参考SDK提供的ApiDemos中关于Camera的例子：

List sizes = parameters.getSupportedPreviewSizes();

Size optimalSize
= getOptimalPreviewSize(sizes, w,
h);
parameters.setPreviewSize(optimalSize.width,
optimalSize.height);

同时，在HTC手机中，设置parameters.setPictureSize(width,height)属性，也会导致黑屏，而在三星手机上则没有问题。还有如果设置setPreviewSize属性的宽高错误的话，拍出的照片也会存在失真等Bug，所以遇到适配问题时，最好的办法就是不设置PreviewSize和PictureSize属性。


getOptimalPreviewSize方法

private Size getOptimalPreviewSize(List sizes, int w, int h)
{

final double
ASPECT_TOLERANCE = 0.05;

double
targetRatio = (double) w / h;

if (sizes ==
null)

return
null;

Size optimalSize
= null;

double minDiff =
Double.MAX_VALUE;

int targetHeight
= h;

// Try to find an
size match aspect ratio and size

for (Size size :
sizes) {

double
ratio = (double) size.width / size.height;

if
(Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)

continue;

if
(Math.abs(size.height - targetHeight) < minDiff) {

optimalSize
= size;

minDiff
= Math.abs(size.height - targetHeight);

}

}

// Cannot find
the one match the aspect ratio, ignore the requirement

if (optimalSize
== null) {

minDiff
= Double.MAX_VALUE;

for
(Size size : sizes) {

if
(Math.abs(size.height - targetHeight) < minDiff) {

optimalSize
= size;

minDiff
= Math.abs(size.height - targetHeight);

}

}

}

return
optimalSize;

}