Image loader image loading method implemented by Android listview

This article gives an example of how Android listview implements imageloader image loading. Share with you for your reference, as follows:

I've been busy doing projects recently, and I'm also busy today. I want to write a blog to consolidate the knowledge used in the application before. Previously, we may and must have encountered the problem of asynchronous loading of pictures. However, we may also encounter the problem of loading pictures twice or multiple times, which is caused by the characteristics of listview. The specific reasons are not discussed here, or oom and other problems. Today I want to talk about an open source framework imageloader, which I think is very easy to use.

The address of the framework in GitHub. https://github.com/nostra13/Android-Universal-Image-Loader 。 Let's first look at the characteristics of this open source inventory:

① 2. Multi thread downloading of pictures, which can come from the network, file system, project folder, assets and drawable medium ②. Support arbitrary configuration of imageloader, such as thread pool, picture downloader, memory cache strategy, hard disk cache strategy, picture display options and other configurations ③. Support memory cache of pictures, File system cache or SD card cache ④. Support the monitoring of picture download process ⑤. Cut the bitmap according to the size of the control (ImageView) to reduce the excessive memory occupied by the bitmap ⑥. Better control the picture loading process, such as pausing the picture loading and restarting the picture loading. It is generally used in listview and GridView to pause the picture loading during sliding, Load pictures when sliding stops ⑦. Provide loading pictures on slow networks

Let's get to the point:

1. We need to go to GitHub to download the jar package of imageloader, which has been given on the website, and then put it in your development environment. Everyone will know how to operate it.

2. Configure Android manifest file

3. First, we need to create a new myapplication, inherit from the application, and configure imageloader in oncreate. You can refer to the following code.

It can be called in onCreate.

4. Set picture display properties

5. Display the picture by calling displayimage

This completes the loading of the picture.

Of course, there is a small problem with this, that is, the image will be loaded twice. The reason is that the image will be cached once before downloading and again later. The specific reason can be determined by Baidu. I won't discuss it here. Just replace the above code with the following one. Direct code

Well, that's all for imageloader. I hope you can point out any problems.

More readers interested in Android related content can view the special topics of this site: summary of Android graphics and image processing skills, introduction and advanced tutorial of Android development, summary of Android debugging skills and common problem solving methods, summary of Android basic component usage, summary of Android view skills, summary of Android layout skills, and Android control usage summary

I hope this article will help you in Android programming.