目标 C：如何将图像放入 imageview

Question

我正在使用 UIImagePickerController 为我的应用选择图像。但是我遇到了所选图像的纵横比问题。图像显示大于其原始尺寸并且未显示完整图像。我尝试将UIViewContentMode 属性更改为所有可能的值仍然没有用。任何人都可以指导我如何使它工作？

这里是 UIImagePickerController 委托的实现

- (void)imagePickerController:(UIImagePickerController *)picker
        didFinishPickingImage:(UIImage *)image
                  editingInfo:(NSDictionary *)editingInfo {

     self.imageProfile.contentMode = UIViewContentModeScaleAspectFit;
     self.imageProfile.image = image;
     [picker dismissViewControllerAnimated:YES completion:nil];

}

Answer 1

当您使用自动布局时，首先使用您的图像高度约束定义一个出口，称为imageHeightConstraint，然后使用这个修改您的代码

- (void)imagePickerController:(UIImagePickerController *)picker
        didFinishPickingImage:(UIImage *)image
                  editingInfo:(NSDictionary *)editingInfo {

     float aspectRatio = image.size.height/image.size.width
     self.imageProfile.contentMode = UIViewContentModeScaleAspectFit;
     self.imageProfile.image = image;
     [self.imageHeightConstraint setConstant: self.imageProfile.frame.size.width * aspectRatio];
     [picker dismissViewControllerAnimated:YES completion:nil];
}

---

已编辑

这是我的代码

#import "ViewController.h"

@interface ViewController () <UINavigationControllerDelegate,UIImagePickerControllerDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *imageProfile;
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *imageConstraintHeigth;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}


- (IBAction)selectImage:(id)sender {

    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.allowsEditing = YES;
    picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    [self presentViewController:picker animated:YES completion:NULL];
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(nullable NSDictionary<NSString *,id> *)editingInfo{

    float aspectRatio = image.size.height/image.size.width;
    self.imageProfile.contentMode = UIViewContentModeScaleAspectFit;
    self.imageProfile.image = image;
    //this if you need adjust heigth according to width
    [self.imageConstraintHeigth setConstant: self.imageProfile.frame.size.width * aspectRatio];

    [picker dismissViewControllerAnimated:YES completion:nil];
}



@end

这是我的限制

希望对我有帮助，对我来说效果很好