Android 在低版本sdk中没有getSupportedPreviewSizes和getSupportedPictureSizes函数怎么办？

在做camera和SurfaceView做摄像头程序时，需要获取camera支持的相片大小，在低版本sdk中没有getSupportedPictureSizes函数，怎么办呢，请参阅下面的关键代码：

1、定义Size类

public class Size {

/***

* Sets the dimensions for pictures.

*

* @param w the photo width (pixels)

* @param h the photo height (pixels)

*/

public Size(int w, int h) {
width = w;
height = h;
}

/***

* Compares {@code obj} to this size.

*

* @param obj the object to compare this size with.

* @return {@code true} if the width and height of {@code obj} is the

*         same as those of this size. {@code false} otherwise.

*/

@Override

public boolean equals(Object obj) {
if (!(obj instanceof Size)) {
return false;
}
Size s = (Size) obj;
return width == s.width && height == s.height;
}

@Override

public int hashCode() {
return width * 32713 + height;
}

/*** width of the picture */
public int width;

/*** height of the picture */
public int height;
}

2、定义CameraHelper类

import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import android.hardware.Camera;

public class CameraHelper {

private static final String KEY_PREVIEW_SIZE = "preview-size";
private static final String KEY_PICTURE_SIZE = "picture-size";
private static final String SUPPORTED_VALUES_SUFFIX = "-values";
private Camera.Parameters mParms;

public CameraHelper(Camera.Parameters parm) {
this.mParms = parm;
}

public List<Size> GetSupportedPreviewSizes() {
String str = mParms.get(KEY_PREVIEW_SIZE + SUPPORTED_VALUES_SUFFIX);
return splitSize(str);
}

public List<Size> GetSupportedPictureSizes() {
String str = mParms.get(KEY_PICTURE_SIZE + SUPPORTED_VALUES_SUFFIX);
return splitSize(str);
}

private ArrayList<Size> splitSize(String str) {
if (str == null)
return null;
StringTokenizer tokenizer = new StringTokenizer(str, ",");
ArrayList<Size> sizeList = new ArrayList<Size>();
while (tokenizer.hasMoreElements()) {
Size size = strToSize(tokenizer.nextToken());
if (size != null)
sizeList.add(size);
}
if (sizeList.size() == 0)
return null;
return sizeList;
}

private Size strToSize(String str) {
if (str == null)
return null;
int pos = str.indexOf('x');
if (pos != -1) {
String width = str.substring(0, pos);
String height = str.substring(pos + 1);
return new Size(Integer.parseInt(width), Integer.parseInt(height));
}
return null;
}

}

其实，主要是通过Camera.Parameters的get方法，然后再解析获取的字符串来代替那些不存在的api。