What's wrong with dynamically adding images to uniapp static files but not displaying them?

With the continuous development of mobile applications, people's demands for applications are becoming more and more diverse. They are not limited to a single function, but also require applications to present richer, dynamic, and personalized interfaces and effects. As a mobile development framework with excellent functions and experience, uniapp just meets this demand.

However, during the development process using uniapp, we may encounter such a problem: dynamically added images in static files cannot be displayed. This may cause problems with our application interface and seriously affect the user experience. Below I will explain how to solve this problem from three aspects: the process of adding static file images, possible problems, and solutions.

1. The process of adding static files and images

In uniapp, static files refer to files placed in the static directory of the project. They will be copied directly to dist directory and plays an important role. In actual development, if we need to dynamically add images to static files, we need to follow the following steps:

1. Create a new folder under the static folder and name it images or another name you like. .
2. Put the pictures you want to add in this folder and make sure the format and size of the pictures are correct.
3. Call the image through the img tag in the page. The path of src is /static/images/image name.extension.

The above is the basic process of adding static files and images. It seems very simple, but in actual development, you will encounter some problems.

2. Possible problems

1. Unable to find the image path

This is one of the headaches we may encounter when developing using uniapp . When adding a picture, it is easy to make a spelling mistake or write the wrong path, causing the picture path to be unable to be found. This situation is usually resolved by checking the path and spelling errors.

2. Incomplete or unclear picture display

This problem is usually caused by the picture size being too large or too small. In uniapp, the maximum size of pictures is 5M. Pictures that are too large may not be fully displayed, while pictures that are too small will affect the user experience due to distortion. Solving this problem requires reasonable resizing of the image.

3. Dynamicly added pictures cannot be displayed

This is one of the important problems we may encounter when developing using uniapp. If we dynamically add a picture when the project is running, but it cannot be displayed on the page, this will have a great negative impact on our application experience. Next we will elaborate on how to solve this problem.

3. Solution

As mentioned above, the inability to display dynamically added images is one of the important problems we may encounter, so how to solve it? Two solutions are provided below for your reference:

1. Cache cleaning method

When we dynamically add pictures when running the uniapp application, the actual path to the picture is not static /images/ path, but is stored in the image cache directory of uniapp. Therefore, if dynamically added images cannot be displayed, we can try to clear uniapp's cache.

The specific operation method is as follows:

① Open the official debugging tool in WeChat development tools.
② Open the "Console" panel of the development tool and find the "Clear Cache" option.
③ Select to clear uniapp’s cache in the “Clear Cache” option.
④ Check whether the picture can be displayed normally.

2. Image preloading method

If our application needs to dynamically add a large number of images, the efficiency of the cache clearing method may be reduced. At this time we can try Use image preloading technology to solve this problem. The specific operation method is as follows:

① Define an array in the data of the page to store the image path to be added.
② Load the image asynchronously through uni.getImageInfo in onLoad of the page, and save the image path in the array defined in data.
③ Listen to the image loading completion event in onReady of the page, and call this.setData() to update the src of the image display when the event is triggered.

By trying the above two methods, we can effectively solve the problem that dynamically added pictures cannot be displayed in uniapp, so that our application can present rich and vivid interface effects more smoothly and naturally.

Summary:

Through the above explanation, we can summarize the following key points:

1. Adding static files and images needs to strictly follow the specifications and ensure the path and spelling correct.
2. If the image size is too large or too small, it may cause incomplete display or distortion, so you need to pay attention to reasonable adjustments.
3. The inability to display dynamically added images is one of the important problems we may encounter, which can be solved by cache cleaning and image preloading.

Finally, I hope that the above analysis and solutions can help everyone with the problems of adding static files and images encountered during the development of uniapp.

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