iOS 无法加载图像文件以编程方式从 View Controller 查看

Question

我有一个 View ，其属性应该从我的 View Controller 获取 NSString 并显示图像。如果我在我的 View 中使用“320x213-1.png”对 locationImageFile 进行硬编码，则图像会正确显示，但如果我尝试从我的 View Controller 设置 locationImageFile，则图像不会出现。我觉得我缺少一些非常基本的东西。旁注:我似乎可以毫无问题地从我的 View Controller 设置 locationTitle 属性。

LocationViewController.m

#import "LocationViewController.h"
#import "LocationView.h"

@implementation LocationViewController
{
    LocationView *_locationView;
}

- (void)loadView
{
    CGRect frame = [[UIScreen mainScreen] bounds];
    _locationView = [[LocationView alloc] initWithFrame:frame];
    [self setView:_locationView];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Do any additional setup after loading the view.

    _locationView.locationTitle.text = aLocation.name;
    _locationView.locationImageFile = @"320x213-1.png";

}

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

@end

LocationView.m

#import "LocationView.h"

@implementation LocationView

@synthesize locationTitle;
@synthesize locationImageFile;


- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code

        [self setBackgroundColor: [UIColor blueColor]];

        // Image container
        UIImage *locationImage = [UIImage imageNamed:locationImageFile];
        UIImageView *locationImageContainer = [[UIImageView alloc] initWithImage:locationImage];
        [locationImageContainer setTranslatesAutoresizingMaskIntoConstraints:NO];
        locationImageContainer.backgroundColor = [UIColor yellowColor];
        [self addSubview:locationImageContainer];

        // Text line
        locationTitle = [[UILabel alloc]init];
        [locationTitle setTranslatesAutoresizingMaskIntoConstraints:NO];
        locationTitle.backgroundColor = [UIColor whiteColor];
        [self addSubview:locationTitle];

        }
    return self;
}

@end

Answer 1

我认为这是因为 loadView 方法的调用早于 viewDidLoad 方法。

所以当您设置 _locationView.locationImageFile = @"320x213-1.png"; 时，containerView 的图像没有被设置。

你可以考虑将 locationImageContainer 声明为 locationView 的属性，并直接设置它的图像。就像

_locationView.locationImageContainer.image = [UIImage imageNamed:@"320x213-1.png"];

而不是将 locationImageFile 设置为属性。