以编程方式访问iPad启动图像？

Question

我在Images.xcassets中使用LaunchImage.launchimage管理启动图像。但我也想在应用程序内部使用启动图像。

我阅读了这个答案:

文档说明UIImage上的imageNamed:方法应该会自动神奇地选择正确的版本。

所以，我使用了这段代码：

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

在使用 iPhone 4、5、6 和 6+ 时，它能够正常工作并获取正确的启动图像，但是在 iPad retina 上工作时，它返回 [e-mail] ，这是 iPhone 4s 的启动图像 640 x 960 像素

那么我该如何通过编程访问 iPad 的正确启动图像呢？

LaunchImage 文件夹中 Contents.json 的内容。

{
  "images" : [
    {
      "extent" : "full-screen",
      "idiom" : "iphone",
      "subtype" : "736h",
      "filename" : "[e-mail]",
      "minimum-system-version" : "8.0",
      "orientation" : "portrait",
      "scale" : "3x"
    },
    {
      "extent" : "full-screen",
      "idiom" : "iphone",
      "subtype" : "667h",
      "filename" : "[e-mail]",
      "minimum-system-version" : "8.0",
      "orientation" : "portrait",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "iphone",
      "extent" : "full-screen",
      "minimum-system-version" : "7.0",
      "filename" : "[e-mail]",
      "scale" : "2x"
    },
    {
      "extent" : "full-screen",
      "idiom" : "iphone",
      "subtype" : "retina4",
      "filename" : "[e-mail]",
      "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" : "[e-mail]",
      "scale" : "2x"
    },
    {
      "orientation" : "portrait",
      "idiom" : "iphone",
      "extent" : "full-screen",
      "filename" : "[e-mail]",
      "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"
  }
}

- MujtabaFR

Answer 1

我用一种冗长的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"];
        }
    }
}

- MujtabaFR

Answer 2

LaunchImage.launchimage

你真的在使用Images.xcassets来管理启动图片吗？难道不是使用LaunchImage.launchimage吗？

如果是这样，就会产生混淆。你不能从LaunchImage.launchimage中使用[UIImage imageNamed:@"LaunchImage"];进行加载。

规范名称

• LaunchImage.png
• [e-mail]
• [e-mail]
• [e-mail]
• [e-mail]
• LaunchImage-700-Landscape@2x~ipad.png

LaunchImage-700-Portrait@2x~ipad.png 不在列表中。

- SwiftArchitect

---

是的，我正在使用位于Images.xcassets中的LaunchImage.launchimage。 - MujtabaFR

即使将 LaunchImage-700-Portrait~ipad.png 重命名为 LaunchImage-700~ipad.png 并编辑 Contents.json，仍然返回 iPhone 4s 启动图像。 - MujtabaFR

Answer 3

我相信那些扩展名（例如-700-Landscape@2x~ipad）是不可识别的。

为了测试目的，将以下项目添加到您的Contents.json中：

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

现在尝试使用imageNamed:方法。

或者尝试使用带有完整图片名称的imageNamed:方法：

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

- hasan

---

如果这没有解决你的问题，你需要获取Images.xcassets包。请确认。我将添加获取Images.xcassets包的代码。 - hasan

抱歉..即使将LaunchImage-700-Portrait~ipad.png重命名为LaunchImage.png并编辑了Contents.json，仍然没有改变，仍然返回iPhone 4s图像。 - MujtabaFR

但是，如果像这样使用完整的图像名称 [UIImage imageNamed:@"LaunchImage-700-Landscape~ipad.png"]，它可以工作。但是，这需要更多的代码才能正常工作。 - MujtabaFR

我知道。这对我也从来没有起作用过。我相信苹果从未真正为所有这些扩展提供100%的支持。只有一些简单的扩展，如@2x才能工作。 - hasan