我正在尝试在照片应用程序中调整图像的大小,但尚未成功。我是iOS上调整照片大小的新手,但是我发誓我做的不错,但是我的日志显示:
Error: <WUTModelImageUploadReq>
[photo]: <nil>
[extension]: <nil>
</WUTModelImageUploadReq>
我正在尝试将'scaleImage'设置为AsyncPostFeed.m中的图像
这是我的代码:
UIImage + Scaling.m
@implementation UIImage (Scaling)
- (UIImage *)scaleImageToSize:(CGSize)newSize {
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
CGFloat originX = 0.0;
CGFloat originY = 0.0;
CGRect destinationRect =
CGRectMake(originX, originY, newSize.width, newSize.height);
[self drawInRect:destinationRect];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
@end
WUTPostViewController.m:
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *selectedImage = _imageForPost;
CGSize scaleSize = CGSizeMake(200.0f, 200.0f);
UIImage *scaleImage =
[selectedImage scaleImageToSize:scaleSize];
[self.imageViewForPost setImage:scaleImage];
...
}
WUTPostViewController.h:
@interface WUTPostViewController : WUTCommonViewController <UITextViewDelegate,UIAlertViewDelegate>
@property (strong, nonatomic) IBOutlet UILabel *lblUserName;
@property (strong, nonatomic) IBOutlet UIImageView *imageViewForPost;
@property (strong, nonatomic) IBOutlet UITextView *tvDesription;
@property (strong,nonatomic) UIImage *imageForPost;
@property (strong,nonatomic) UIImage *scaleImage;
- (void)wsPostLikeSuccessCallbackForPostId;
- (void)wsPostLikeFailCallbackWithMessage:(NSString *)errorMessage;
@end
AsyncPostFeed.m:
- (void)uploadPhoto {
WUTModelImageUploadReq *imageUploadReq = [[WUTModelImageUploadReq alloc]init];
// I'm trying to set scaleImage here
imageUploadReq.photo = [self encodeToBase64String:[UIImage imageWithData:UIImageJPEGRepresentation(self.viewControllerPost.scaleImage, 0.07f)]];
imageUploadReq.extension = @"jpg";
NSLog(@"Error: %@", imageUploadReq);
void (^wsSuccessHandler)(AFHTTPRequestOperation *operation, NSDictionary* responseObject) = ^(AFHTTPRequestOperation *operation, id responseObject){
NSLog(@"Pull Feed responseObject %@",responseObject);
NSError *error;
WUTModelPostImageResponse *wsResponse = [[WUTModelPostImageResponse alloc]initWithDictionary:(NSDictionary *)responseObject error:&error];
if (error) {
errorMessage = @"Failure to upload image.";
NSLog(@"Error: %@", error);
[self postExecuteFail];
}else{
if (wsResponse.success) {
WUTModelImage *imageTemp = [wsResponse.data firstObject];
[postItem setObject:imageTemp.photo forKey:@"photo"];
[self uploadPostFeed];
}else{
errorMessage = @"Failure to upload image.";
NSLog(@"Error: %@", error);
[self postExecuteFail];
}
}
};
更新
看起来像你忘了局部变量设置scaleImage
到scaleImage
财产WUTPostViewController
类。
尝试以下代码(最后一行应该可以解决问题):
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *selectedImage = _imageForPost;
CGSize scaleSize = CGSizeMake(200.0f, 200.0f);
UIImage *scaleImage =
[selectedImage scaleImageToSize:scaleSize];
[self.imageViewForPost setImage:scaleImage];
self.scaleImage = scaleImage;
...
}
原始答案
您的调整大小算法是正确的。我在我的项目中使用了相同的工具,并且效果很好。
看起来像您向对象发送scaleImageToSize:
消息nil
。这就是为什么此消息的结果为的原因nil
。
您可以通过以下方式更新代码来验证此假设:
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *selectedImage = _imageForPost;
NSAssert(selectedImage != nil, @"Selected image is nil");
CGSize scaleSize = CGSizeMake(200.0f, 200.0f);
UIImage *scaleImage =
[selectedImage scaleImageToSize:scaleSize];
[self.imageViewForPost setImage:scaleImage];
...
}
如您所见,我添加了NSAssert
呼叫,因此如果所选图像为nil,您的应用程序将崩溃,并显示所提供的消息。
如果NSAssert
被触发,则需要查找问题的根本原因。基本上,您需要_imageForPost
在viewDidLoad
调用方法之前验证变量是否已初始化。
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