我有一个支持iOS8及以后版本的应用程序，内置在Xcode 7中，我使用XIB作为启动屏幕(我没有启动图像)。视图包含一个带有应用版本的UILabel，以及两个带有图像的UIImageViews，这两个图像都出现在images中。xcassets:标志和启动图像。

当我启动应用程序时，UILabel和logo图像显示正确，但如果我在带有iOS9的iPad Air 2上运行应用程序，启动图像就不能显示。我在运行iOS8的Air和Mini上进行了测试，在iPad 2、iPad Air和iPad Air 2的iOS9模拟器上进行了测试，图像在所有这些模拟器上都显示正确。

我运行了一些基本的故障排除，看看我是否能找出发生了什么，但我还没能解决它，我能看到的图像之间的唯一区别是，工作和一个失败的是，当我添加到资产…

以下是我所知道的:

The UIImageView for the splash image is in the correct place, at the correct size. I can tell this because I set its background color to green just to make sure. The view is there, but the image does not appear. So I'm assuming that the view is not to blame. Setting the UIImageView for the splash image to also use the logo image makes the logo image appear in the correct place for the view. This also leads me to assume that the view is not to blame. The UIImage that I am using in the splash image view is used elsewhere in the app and appears fine in those other views (the logo image is also used elsewhere in the app and appears fine). So I'm assuming that the image is valid and having it appear in other views is not a problem. I've confirmed that the settings of the UIImages for the logo and splash in the xcassets file are the same. They are set to Universal, Any width and height, multiple scale factors, rendered as default. There is one difference - the logo has 1x, 2x and 3x scales while the splash image only has 1x and 2x, but I have also tried using UIImages with only 1x, and 1x and 2x values in the UIView and they work (if they were added to the project some time ago). Adding another image of a different size or format (PNG and JPG) to my xcassets and using that UIImage in the UIImageView for the splash image also fails to display. Adding another UIImageView to the XIB file and allocating it a UIImage that was already in the xcassets works, the image appears in the loading screen. Copying and renaming the image files used for the logo and adding them to the project then using that UIImage in the splash view also fails to display. I have tried cleaning the project, restarting the development machine, and deleting the app from the Air 2 and reinstalling it just in case that was a problem.

这最后三个步骤使我相信，在项目文件生命周期的某一点之后添加的图像存在一些问题。当我昨天更新到Xcode 7时，splash图像最初是在Xcode 6中添加的，但logo图像(也添加到Xcode 6中)是在几个月前添加的。

我已经查看了logo图像和splash图像的json文件，它们似乎具有相同的格式。我还浏览了pbxproj文件，寻找不同之处，但我找不到任何不同之处。

所以我想知道是否有人知道为什么我在Air 2上添加的这些新图像在启动屏幕上不显示?我一直在阅读的其他有关未出现图像的问题似乎都与Launch images有关，或与XIB文件中具有关联类的图像有关，这两个问题在这里似乎都不相关。

我的代码在普通设备上工作正常，但在视网膜设备上产生模糊的图像。

有人知道我的问题的解决方案吗?

+ (UIImage *) imageWithView:(UIView *)view
{
    UIGraphicsBeginImageContext(view.bounds.size);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage * img = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return img;
}

我正在iOS 3.1.3 iPhone上测试我的iPhone应用程序。我正在使用UIImagePickerController选择/捕获图像:

UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
[imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera];
[imagePicker setDelegate:self];
[self.navigationController presentModalViewController:imagePicker animated:YES];
[imagePicker release];



- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    self.image = [info objectForKey:UIImagePickerControllerOriginalImage];
    imageView.image = self.image;
    [self.navigationController dismissModalViewControllerAnimated:YES];
    submitButton.enabled = YES;
}

然后在某个时候，我使用ASI类将它发送到我的web服务器:

ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString:@"http://example.com/myscript.php"]];
[request setDelegate:self];
[request setStringEncoding:NSUTF8StringEncoding];
[request setShouldContinueWhenAppEntersBackground:YES];
//other post keys/values
[request setFile:UIImageJPEGRepresentation(self.image, 100.0f) withFileName:[NSString stringWithFormat:@"%d.jpg", [[NSDate date] timeIntervalSinceNow]] andContentType:@"image/jpg" forKey:@"imageFile"];
[request startAsynchronous];

存在的问题: 当我拿着iPhone拍照时，照片会被上传到服务器，就像你期望的那样。手持竖屏拍照时，上传的照片是旋转90度后观看的。

我的应用程序被设置为只在纵向模式(倒置和常规)下工作。

我怎样才能使图像始终显示正确的方向后上传?

在UIImageView中显示的图像是正确的(直接在拍照后)，但在服务器上查看则不然。

在我的iPhone应用程序中，我用相机拍了一张照片，然后我想把它调整为290*390像素。我用这个方法来调整图像的大小:

UIImage *newImage = [image _imageScaledToSize:CGSizeMake(290, 390)
                         interpolationQuality:1];    

它工作得很好，但它是一个没有记录的功能，所以我不能再在iPhone OS4上使用它了。

所以…调整UIImage大小最简单的方法是什么?

我有一个名为theImageView的UIImageView, UIImage是单色的(透明背景)，就像下面左边的黑色心形。我如何在iOS 7或更高的系统中，根据iOS 7+导航栏图标中使用的色调方法，以编程方式更改此图像的色调颜色?

这个方法也适用于WatchKit的Apple Watch应用程序吗?

我想从我的应用程序中的URL加载图像，所以我首先尝试了Objective-C和它的工作，但是，与Swift，我有一个编译错误:

'imageWithData'不可用:使用对象构造'UIImage(data:)'

我的函数:

@IBOutlet var imageView : UIImageView

override func viewDidLoad() {
    super.viewDidLoad()

    var url:NSURL = NSURL.URLWithString("http://myURL/ios8.png")
    var data:NSData = NSData.dataWithContentsOfURL(url, options: nil, error: nil)

    imageView.image = UIImage.imageWithData(data)// Error here
}

在objective - c中:

- (void)viewDidLoad {
    [super viewDidLoad];

    NSURL *url = [NSURL URLWithString:(@"http://myURL/ios8.png")];
    NSData *data = [NSData dataWithContentsOfURL:url];

    _imageView.image = [UIImage imageWithData: data];
    _labelURL.text = @"http://www.quentinroussat.fr/assets/img/iOS%20icon's%20Style/ios8.png";
 }

有人能解释一下为什么imageWithData:不能与Swift一起工作，我该如何解决这个问题。