iOS：缩放适合或在UIWebView中填充本地图像？

Question

I'm using a UIWebView to display a gif animation stored on local disk, since UIImageView doesn't work with gif format. Here is how I did it:

[webView loadData:imageData MIMEType:@"image/gif" textEncodingName:nil baseURL:nil];

I found the solution from here .

The problem now is the position of the image. See the screen capture below. The UIWebView frame is (20, 20, 280, 280). But the image is on the top left with its content size.

How do I make this image scale to fit the UIWebView frame? I've tried "scalesPageToFit = YES" and "contentMode = UIViewContentModeScaleAspectFit", not working. Maybe specifying something in html? Please help.

Answer 1

Actually, there are a few ways to use a animated GIF in imageview, and I think it's a lot better than use a webView just for this purpose.

I personnaly used SDWebImage, that can be easily used with cocoa pods. See this: https://github.com/rs/SDWebImage

After integreted SDWebImage to your project, just import this header:

#import "UIImage+GIF.h"

And set the gif image like this:

self.imageView.image = [UIImage sd_animatedGIFNamed:@"loading"] //loading.gif it's a gif image inside the project bundle

If you still insist to use a webview, the only way to resize a image inside it, it's with javascript.

Select the image with javascript and edit it's height and width properties. You can run javascript code in a webView with the function below:

 [self.webView stringByEvaluatingJavaScriptFromString:@"-javascript code here-"];

So, in your case, it will be something like this:

[self.webView stringByEvaluatingJavaScriptFromString:@"document.getElementsByTagName('img')[0].style.width = '280px'"];

[self.webView stringByEvaluatingJavaScriptFromString:@"document.getElementsByTagName('img')[0].style.height = '280px'"];