以编程方式访问 iPad 启动图像？

Question

我在Images.xcassets 中使用LaunchImage.launchimage 来管理启动图像。但我也在尝试使用应用内的启动图像。

我读过this answer：

文档表明 UIImage 上的 imageNamed: 方法 应该自动地选择正确的版本

所以，我使用了这个代码

UIImageView *backImage = [UIImageView new];
backImage.image = [UIImage imageNamed:@"LaunchImage"];

在 iPhone 4、5、6、6+ 上工作时，它运行良好并获得正确的 LaunchImage，但在 iPad Retina 上工作时，它返回 LaunchImage-700@2x.png，这是 iPhone 4s 640 x 960 pixels

那么我怎样才能以编程方式访问 iPad 的正确 LaunchImage 呢？？

LaunchImage文件夹中Contents.json的内容

{
  "images" : [
    {
      "extent" : "full-screen",
      "idiom" : "iphone",
      "subtype" : "736h",
      "filename" : "LaunchImage-800-Portrait-736h@3x.png",
      "minimum-system-version" : "8.0",
      "orientation" : "portrait",
      "scale" : "3x"
    },
    {
      "extent" : "full-screen",
      "idiom" : "iphone",
      "subtype" : "667h",
      "filename" : "LaunchImage-800-667h@2x.png",
      "minimum-system-version" : "8.0",
      "orientation" : "portrait",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "iphone",
      "extent" : "full-screen",
      "minimum-system-version" : "7.0",
      "filename" : "LaunchImage-700@2x.png",
      "scale" : "2x"
    },
    {
      "extent" : "full-screen",
      "idiom" : "iphone",
      "subtype" : "retina4",
      "filename" : "LaunchImage-700-568h@2x.png",
      "minimum-system-version" : "7.0",
      "orientation" : "portrait",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "minimum-system-version" : "7.0",
      "filename" : "LaunchImage-700-Portrait~ipad.png",
      "scale" : "1x"
    },
    {
      "orientation" : "landscape",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "minimum-system-version" : "7.0",
      "filename" : "LaunchImage-700-Landscape~ipad.png",
      "scale" : "1x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "minimum-system-version" : "7.0",
      "filename" : "LaunchImage-700-Portrait@2x~ipad.png",
      "scale" : "2x"
    },
    {
      "orientation" : "landscape",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "minimum-system-version" : "7.0",
      "filename" : "LaunchImage-700-Landscape@2x~ipad.png",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "iphone",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700.png",
      "scale" : "1x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "iphone",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700@2x.png",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "iphone",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700-568h@2x.png",
      "subtype" : "retina4",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700-Portrait~ipad.png",
      "scale" : "1x"
    },
    {
      "orientation" : "landscape",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700-Landscape~ipad.png",
      "scale" : "1x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700-Portrait@2x~ipad.png",
      "scale" : "2x"
    },
    {
      "orientation" : "landscape",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "filename" : "LaunchImage-700-Landscape@2x~ipad.png",
      "scale" : "2x"
    }
  ],
  "info" : {
    "version" : 1,
    "author" : "xcode"
  }
}

Answer 1

我认为这些扩展（例如 -700-Landscape@2x~ipad）无法识别。

将以下项目添加到您的 Contents.json 中，仅用于测试目的：

{
      "orientation" : "landscape",
      "idiom" : "ipad",
      "extent" : "full-screen",
      "filename" : "LaunchImage.png",
      "scale" : "1x"
}

现在试试 imageNamed: 方法。

或者试试 imageNamed: 和图片全名：

backImage.image = [UIImage imageNamed:@"LaunchImage-700-Landscape~ipad.png"];

Answer 2

LaunchImage.launchimage

您真的使用Images.xcassets 来管理启动图像吗？ 你不是用LaunchImage.launchimage 代替吗？

如果是这样，就会出现混乱。您无法使用来自LaunchImage.launchimage 的[UIImage imageNamed:@"LaunchImage"]; 加载。

规范名称

• LaunchImage.png
• LaunchImage@2x.png
• LaunchImage-700@2x.png
• LaunchImage-568h@2x.png
• LaunchImage-700-568h@2x.png
• LaunchImage-700-Landscape@2x~ipad.png

LaunchImage-700-肖像@2x~ipad.png不在列表中。

Answer 3

我已经用一个长方法解决了这个问题

BOOL deviceIsIpad = NO;
if ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad ) {
    deviceIsIpad = YES;
}

if (!deviceIsIpad) {
    backImage.image = [UIImage imageNamed:@"LaunchImage"];
} else {
    UIInterfaceOrientation interfaceOrientation = self.interfaceOrientation;
    CGFloat screenScale = [[UIScreen mainScreen] scale];
    if (interfaceOrientation == UIDeviceOrientationPortrait || interfaceOrientation == UIDeviceOrientationPortraitUpsideDown){
        if (screenScale > 1) {
            backImage.image = [UIImage imageNamed:@"LaunchImage-700-Portrait@2x~ipad.png"];
        } else {
            backImage.image = [UIImage imageNamed:@"LaunchImage-700-Portrait~ipad.png"];
        }
    } else {
        if (screenScale > 1) {
            backImage.image = [UIImage imageNamed:@"LaunchImage-700-Landscape@2x~ipad.png"];
        } else {
            backImage.image = [UIImage imageNamed:@"LaunchImage-700-Landscape~ipad.png"];
        }
    }
}