Unity3d 屏幕截图。并保存。iOS

- ( void ) imageSaved: ( UIImage *) image didFinishSavingWithError:( NSError *)error
    contextInfo: ( void *) contextInfo
{
    NSLog(@"保存结束");
    if (error != nil) {
        NSLog(@"有错误");
    }
}
void _SavePhoto(char *readAddr)
{
    NSString *strReadAddr = [NSString stringWithUTF8String:readAddr];
    UIImage *img = [UIImage imageWithContentsOfFile:strReadAddr];
    NSLog([NSString stringWithFormat:@"w:%f, h:%f", img.size.width, img.size.height]);
    PhotoManager *instance = [PhotoManager alloc];
    UIImageWriteToSavedPhotosAlbum(img, instance,
        @selector(imageSaved:didFinishSavingWithError:contextInfo:), nil);
}  

using UnityEngine;
using System.Runtime.InteropServices;  

public class TestSavePhoto : MonoBehaviour
{
    [DllImport("__Internal")]
    private static extern void _SavePhoto(string readAddr);  

    private string _cptrAddr;  

    private void OnGUI()
    {
        if (GUILayout.Button("_SavePhoto!", GUILayout.Height(), GUILayout.Width()))
        {
            Debug.Log("_SavePhoto");
            var readAddr = Application.persistentDataPath + "/" + _cptrAddr;
            _SavePhoto(readAddr);
        }
        if (GUILayout.Button("TakePhoto", GUILayout.Height(), GUILayout.Width()))
        {
            Debug.Log("TakePhoto");
            var cptrAddr = "testpic"; //捕捉地址
            var readAddr = Application.persistentDataPath + "/" + cptrAddr;//读取地址，这两个地址在iOS里不一样
            Debug.Log("cptr:" + cptrAddr + ", read:" + readAddr);
            Application.CaptureScreenshot(cptrAddr);
            _cptrAddr = cptrAddr;
        }
    }
}