What's wrong with the uniapp cache object being lost after restarting?

With the popularization of mobile Internet and the continuous updating of technology, developing mobile applications has become the choice of more and more developers. Among them, uniapp is a cross-platform development framework that can be developed on multiple platforms at the same time. At the same time, caching is also a very important part of mobile applications. However, when using uniapp to develop applications, we may encounter some caching problems, such as the problem of cache object being lost upon restart. This article will discuss this problem and its solution.

1. Confirm the problem

When dealing with caching problems, you first need to confirm the source and specific manifestations of the problem. When using uniapp to develop applications, we may use uniapp's caching API, including setData, getStorageSync, setStorageSync, etc., to save and obtain data. However, in some cases, we will find that some object type data will be lost after the application is restarted, causing us to reload the data. This situation is the problem of cache object being lost after restarting.

2. Solution

For the problem of cache object restart loss, we can adopt the following solutions:

1. Use JSON.stringify and JSON.parse methods

First, we can convert the object object into a JSON string and store it using local storage methods such as LocalStorage or SessionStorage. The specific code is as follows:

//设置缓存
var obj = {'name':'test','age':21};
localStorage.setItem('myObj',JSON.stringify(obj));
//获取缓存
var objStr = localStorage.getItem('myObj');
var obj = JSON.parse(objStr);

Use the JSON.stringify and JSON.parse methods Convert object to JSON string and back to object. This can avoid the problem of object parsing errors in the cache and ensure that the cache can be stored and retrieved normally.

2. Use the uni.setStorageSync and uni.getStorageSync methods

In addition, we can use the uni.setStorageSync and uni.getStorageSync methods provided by uniapp for caching. These two methods will automatically cache the object Type data is converted to string type and saved. The specific code is as follows:

//设置缓存
var obj = {'name':'test','age':21};
uni.setStorageSync('myObj',obj);
//获取缓存
var obj = uni.getStorageSync('myObj');

When using the uni.setStorageSync method to set up the cache, if the data type is object, it will automatically be converted into a string type for storage. Any type of data can be stored using this method. storage. At the same time, when using the uni.getStorageSync method to obtain the cache, type conversion is automatically performed to convert string type data into object type.

3. Use caching plug-in

If the above two methods still cannot solve the problem, we can consider using caching plug-in. uniapp provides some caching plug-ins, such as H5plus, storagePlus and other plug-ins, which can achieve a more flexible and stable caching method. These plug-ins can not only support ordinary key-value pair storage, but also support the storage of multiple data types, such as binary streams.

4. Summary

Caching is a very important part of mobile application development. Especially for data that needs to be read frequently, caching can greatly improve application efficiency and user experience. However, when using uniapp for development, we may encounter the problem of cache object being lost upon restart. At this point, we can take some solutions, such as using JSON.stringify and JSON.parse methods, using uni.setStorageSync and uni.getStorageSync methods, and using cache plug-ins, etc. Through the application of these methods, we can effectively solve the problem of cache object restart loss and improve application performance and stability.

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