Java tutorial
//package com.java2s; import android.app.Activity; import android.graphics.Point; import android.hardware.Camera; import android.view.Display; import java.util.List; public class Main { public static Camera.Size getOptimalPreviewSize(Activity currentActivity, List<Camera.Size> sizes, double targetRatio) { // Use a very small tolerance because we want an exact match. final double ASPECT_TOLERANCE = 0.001; if (sizes == null) return null; Camera.Size optimalSize = null; double minDiff = Double.MAX_VALUE; // Because of bugs of overlay and layout, we sometimes will try to // layout the viewfinder in the portrait orientation and thus get the // wrong size of preview surface. When we change the preview size, the // new overlay will be created before the old one closed, which causes // an exception. For now, just get the screen size. Point point = getDefaultDisplaySize(currentActivity, new Point()); int targetHeight = Math.min(point.x, point.y); // Try to find an size match aspect ratio and size for (Camera.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. This should not happen. // Ignore the requirement. if (optimalSize == null) { minDiff = Double.MAX_VALUE; for (Camera.Size size : sizes) { if (Math.abs(size.height - targetHeight) < minDiff) { optimalSize = size; minDiff = Math.abs(size.height - targetHeight); } } } return optimalSize; } private static Point getDefaultDisplaySize(Activity activity, Point size) { Display d = activity.getWindowManager().getDefaultDisplay(); d.getSize(size); return size; } }