Android自定义照相机Camera出现黑屏的解决方法

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本文实例讲述了Android自定义照相机Camera出现黑屏的解决方法。分享给大家供大家参考,具体如下:

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<Size> 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<Size> 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;
    }