my camera previewSize shows low resolution

Question

i'm on creating custom camera for android, but camera previewSize is showing low resolution , how can i make that to best preview size

this is the code for i used get previewSize

private Camera.Size getBestPreviewSize(int width, int height) {
        Camera.Size result = null;
        Camera.Parameters p = camera.getParameters();
        for (Camera.Size size : p.getSupportedPreviewSizes()) {
            if (size.width <= width && size.height <= height) {
                if (result == null) {
                    result = size;
                } else {
                    int resultArea = result.width * result.height;
                    int newArea = size.width * size.height;

                    if (newArea > resultArea) {
                        result = size;
                    }
                }
            }
        }
        return result;

    }

results of this code is shows width: 352: height: 288

using below code shows some other resolution

private Camera.Size getBestPreviewSize(int width, int height)
    {
        List<Size> sizes = camera.getParameters().getSupportedPreviewSizes();
        if (sizes == null) return null;

        Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = height;
        int targetWidth = width;

        int minWidthDiff = 0;
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.width - targetWidth) < minDiff) {
                    if(size.width > width) {
                        if (minWidthDiff == 0) {
                            minWidthDiff = size.width - width;
                            optimalSize = size;
                        }
                        else if (Math.abs(size.width - targetWidth) < minWidthDiff) {
                            minWidthDiff = size.width - width;
                            optimalSize = size;

                        }   
                        minDiff = Math.abs(size.width - targetWidth);
                     }
                }
            }
        }

        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;
    }

results of this code width: 640 : height: 480 but still preview looks blur

EDIT: stop preview before using it

camera.stopPreview();
parameters.setPreviewSize(size.width, size.height);
parameters.setRotation(0);