ios - 背景图像在窗口/ View 中太大

Question

我正在玩一个非常小的单 View 应用程序，以了解 View 是如何工作的。我对 iOS 开发非常陌生。我正在使用我放在一起的图像作为我唯一 View 的背景。运行应用程序时，我的背景是巨大的。就好像它被放大或缩放一样。我正在关注 Big Nerd Ranch View 教程，因此我正在使用 UIView 的一个子类，称为 HypnosisView。这是暂时的。值得一提的是，我尝试用作背景的图像正好是 640 x 1136 像素。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.

    CGRect viewFrame = CGRectMake(0, 0, 640, 1136);

    HypnosisView *view = [[HypnosisView alloc] initWithFrame:viewFrame];
    [view setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"BG.png"]]];
    [[self window] addSubview:view];

    self.window.backgroundColor = [UIColor blackColor];
    [self.window makeKeyAndVisible];
    return YES;
}

更新了尝试使用 0、0、320、568 帧实现 UIImageView 的代码。我还创建了一个 320 大小的背景，然后是一个全尺寸的背景，并用正确的标题命名它们。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.

    CGRect viewFrame = CGRectMake(0, 0, 320, 568);


    UIImage *background = [UIImage imageNamed:@"background@2x.png"];
    UIImageView *backgroundView = [[[UIImageView alloc] initWithImage:background] initWithFrame:viewFrame];

    [[self window] addSubview:backgroundView];
    [[self window] sendSubviewToBack:backgroundView];

    self.window.backgroundColor = [UIColor clearColor];
    [self.window makeKeyAndVisible];
    return YES;
}

Answer 1

如果您的 View 框架比您的屏幕大，您的图像也将被剪裁。您可以使用 UIScrollView，将原始图像缩小到一定大小或使用如下代码缩放图像:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.

CGRect viewFrame = CGRectMake(0, 0, 320, 568);


UIImage *background = [UIImage imageNamed:@"BG.png"];

UIImage *scaledImage = [UIImage imageWithCGImage:[background CGImage]
                                           scale:(background.scale * 2.0)
                                     orientation:(background.imageOrientation)];

UIImageView *backgroundView = [[[UIImageView alloc] initWithImage:scaledImage] initWithFrame:viewFrame];

[[self window] addSubview:backgroundView];
[[self window] sendSubviewToBack:backgroundView];

self.window.backgroundColor = [UIColor clearColor];
[self.window makeKeyAndVisible];
return YES;
}

(我的比例因子基于 640x1136 的图像大小)