Question

我将创建一个UIImage，但如果我调试该方法，它将返回nil。我希望有人知道我必须做什么。

我的代码：

返回nil：

UIImage *image1 = imgView.image;

整个代码块：

UIImage *image1 = imgView.image;
NSString *cachedFolderPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
NSString *cachedImagePath = [cachedFolderPath stringByAppendingPathComponent:@"image1.png"];
[UIImagePNGRepresentation(image1) writeToFile:cachedImagePath atomically:YES];

更新

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {

        toolbar.hidden = NO;

        UIImage *image1 = imgView.image;
        NSString *cachedFolderPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
        NSString *cachedImagePath = [cachedFolderPath stringByAppendingPathComponent:@"image1.png"];
        [UIImagePNGRepresentation(image1) writeToFile:cachedImagePath atomically:YES];

    }

    if (picker.sourceType == UIImagePickerControllerSourceTypePhotoLibrary) {

        toolbar.hidden = NO;

        UIImage *image1 = imgView.image;
        NSString *cachedFolderPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
        NSString *cachedImagePath = [cachedFolderPath stringByAppendingPathComponent:@"image1.png"];
        [UIImagePNGRepresentation(image1) writeToFile:cachedImagePath atomically:YES];
    }

    if (picker.sourceType == UIImagePickerControllerSourceTypeSavedPhotosAlbum) {

        toolbar.hidden = NO;

        UIImage *image1 = imgView.image;
        NSString *cachedFolderPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
        NSString *cachedImagePath = [cachedFolderPath stringByAppendingPathComponent:@"image1.png"];
        [UIImagePNGRepresentation(image1) writeToFile:cachedImagePath atomically:YES];
    }

    else{

        toolbar.hidden = NO;

    }

    imgView.image = [info objectForKey:@"UIImagePickerControllerEditedImage"];

    [self dismissViewControllerAnimated:YES completion:nil];
}

Answer 1

首次将imgView.image设置为值时，imagePickerController:didFinishPickingMediaWithInfo:即将结束。因此，第一次调用此方法时，imgView.image将为nil，直到最后设置为：{/ p>

imgView.image = [info objectForKey:@"UIImagePickerControllerEditedImage"];

Answer 2

抱歉，要跳过阅读您的代码，发布适合我的内容。

- (UIImage *) getImage{

    NSString *pathAndFileName = [[NSBundle mainBundle] pathForResource:@"somefile.png"  ofType:nil];
    if ([[NSFileManager defaultManager] fileExistsAtPath:pathAndFileName])
    {
        return [UIImage imageNamed:@"somefile.png"];
    }
    else{
        NSString *t = [self pathToImageInCache:@"somefile.png"];

        if ([[NSFileManager defaultManager] fileExistsAtPath:t]){
            NSLog(@"fiel exists");
            return [[UIImage alloc]initWithContentsOfFile:t];
        }
        else{
            NSLog(@"fiel does not exists");
        }
    }

    return nil;
}

- (NSString *) pathToImageInCache: (NSString *) imageName{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@""];

    NSString *URLImg = [documentsDirectory stringByAppendingPathComponent:imageName];
    return URLImg;
}

Answer 3

我认为你甚至在设置它之前就试图使用imgView.image属性。

使用此行设置imageView.image

imgView.image = [info objectForKey:@"UIImagePickerControllerEditedImage"];

将该行移动到方法的开头。像这样

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

 imgView.image = [info objectForKey:@"UIImagePickerControllerEditedImage"];

if (picker.sourceType == UIImagePickerControllerSourceTypeCamera) {

    toolbar.hidden = NO;

    UIImage *image1 = imgView.image;
    NSString *cachedFolderPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
    NSString *cachedImagePath = [cachedFolderPath stringByAppendingPathComponent:@"image1.png"];
    [UIImagePNGRepresentation(image1) writeToFile:cachedImagePath atomically:YES];

}

UIImage返回nil

3 个答案: