iOS7中的UIImage保存问题：混合问题

Question

以下是模拟器和保存图片的截图：

代码：

UIGraphicsBeginImageContext(self.view.bounds.size);

[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *screenshotImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

//guru - just for simulator
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Image.png"];

[UIImagePNGRepresentation(screenshotImage) writeToFile:filePath atomically:YES];
//end guru

UIImageWriteToSavedPhotosAlbum(screenshotImage, nil, nil, nil);

如何解决此问题？当我使用Xcode4_iOS6构建它时工作正常，但不适用于Xcode5_iOS7。

Answer 1

你可以用这种方式修复它：

    if([self IS_IOS_7])
    {
        UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, TRUE, [[UIScreen mainScreen] scale]);
    }
    else
    {
        UIGraphicsBeginImageContext(self.view.bounds.size);
    }


    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *screenshotImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    UIImageWriteToSavedPhotosAlbum(screenshotImage, nil, nil, nil);

iOS7检查：

-(bool)IS_IOS_7
{
    NSString *currOsVersion = [[UIDevice currentDevice] systemVersion];

    float sysver = [currOsVersion floatValue] ;

    if(sysver >=7.0f)
        return true;

    return false;
}