IOS给任意UIView截屏

//获得某个window的某个subView
UIView *view = [[[[[UIApplication sharedApplication] windows] objectAtIndex:0] subviews] lastObject];
NSInteger index = 0;//用来给保存的png命名
for (UIView *subView in [view subviews]) {//遍历这个view的subViews
if ([subView isKindOfClass:NSClassFromString(@"MKMapView")]) {//找到自己需要的subView
NSLog(@"fund");
//支持retina高分的关键
if(UIGraphicsBeginImageContextWithOptions != NULL)
{
UIGraphicsBeginImageContextWithOptions(subView.frame.size, NO, 0.0);
} else {
UIGraphicsBeginImageContext(subView.frame.size);
}
//获取图像
[subView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//保存图像
NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/%d.png",index];
if ([UIImagePNGRepresentation(image) writeToFile:path atomically:YES]) {
index += 1;
NSLog(@"Succeeded! %@",path);
}
else {
NSLog(@"Failed!");
}
}
}