Question

我有一个mapview，显示从解析中提取的一系列注释。每个都有一个细节视图控制器，显示连接到注释的标签，我试图显示一个图像，但似乎无法搞清楚。这是我目前的代码

    - (void)viewDidLoad
{
    [super viewDidLoad];
    PFObject *gameScore = [PFObject objectWithClassName:@"Arcade"];
    self.title = @"Detail View";
    PFQuery *query = [PFQuery queryWithClassName:@"Arcade"];
    NSString *objectId = gameScore.objectId;
    [query getObjectInBackgroundWithId:ObjectIdentifier block:^(PFObject *gameScore, NSError *error) {
        lblTitle.text = pawpost.title;
        lblPhone.text = pawpost.phone;
        lblAddress.text = pawpost.address;
        __block UIImage *MyPicture = [[UIImage alloc]init];
        PFFile *imageFile = [gameScore objectForKey:@"image"];
        [imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error){
            if (!error) {
                MyPicture = [UIImage imageWithData:data];

            }
        }];
        imgView.image = MyPicture;
    }];

}

我运行它时没有给我任何错误，但它根本不显示..有什么建议吗？

Answer 1

getDataInBackgroundWithBlock是异步执行的，包含这一行的块：

 MyPicture = [UIImage imageWithData:data];

可能在

之后完成

imgView.image = MyPicture;

尝试类似：

[query getObjectInBackgroundWithId:ObjectIdentifier block:^(PFObject *gameScore, NSError *error) {
    lblTitle.text = pawpost.title;
    lblPhone.text = pawpost.phone;
    lblAddress.text = pawpost.address;
    __block UIImage *MyPicture = [[UIImage alloc]init];
    PFFile *imageFile = [gameScore objectForKey:@"image"];
    [imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error){
        if (!error) {
            MyPicture = [UIImage imageWithData:data];
            imgView.image = MyPicture;
        }
    }];

}];

Answer 2

我建议从解析加载图像：使用imgView作为PFImageView的子类，由Parse提供加载图像并分配给imageView。在这种情况下，您可以简单地分配如下图像：

PFImageView * imgView = [[PFImageView alloc] init]; imgView = [UIImage imageNamed:@"..."]; // placeholder image imgView.file = [gameScore objectForKey:@"image"]; [imgView loadInBackground];

https://www.parse.com/docs/ios_guide#ui-imageview/iOS

Answer 3

以上所有解决方案都是正确的，但是想要添加另一种方法来支持SDWebImage的图像缓存或任何类似的库。

我已经回答了类似的问题。看一看 https://stackoverflow.com/a/28761476/2225439

通过Parse iOS显示图像

3 个答案: