What should I do if uniapp has too many levels and cannot obtain dom?

In recent years, with the rapid development of mobile Internet technology, more and more Internet companies have begun to pay attention to development efficiency and user experience. In order to solve the contradiction between development efficiency and user experience, front-end technology is also constantly developing and updating. In this context, uniapp has become a cross-terminal framework that has attracted much attention.

Uniapp is a cross-end framework based on the vue framework. It is compatible with the development of various mainstream mobile and web platforms, greatly improving development efficiency and user experience. However, like other front-end frameworks, uniapp also has its own problems. One of the common problems is that there are many levels and the DOM cannot be obtained.

When developing uniapp projects, we often encounter situations where we need to obtain dom elements. For example, if we need to pop up a prompt box, we must first obtain the pop-up box element before proceeding to the next step. However, in uniapp, due to cross-platform reasons, the hierarchy is encapsulated into a component, which leads to some problems when obtaining DOM elements. Next, let's take a look at this situation.

In uniapp, components are independent of each other. Each component has its own independent scope, which also means that the data and methods in each component are independent. When we get an element of another component in one component, we cannot get the element because their scopes are different. At this time, we need to use the $refs provided by uniapp to obtain elements in other components.

$refs is a special attribute used to mark component elements. It can mark an element of the specified component and store it in the form of key-value pairs in the attribute $refs in the component. When we need to get the element, we only need to use this.$refs['key'] to quickly get the element. The process of using $refs to obtain DOM elements is synchronous, so the correctness and effectiveness of the operation can be guaranteed.

However, in some cases, even if we use $refs, we cannot get the dom element. This problem generally occurs when uniapp has many levels, such as obtaining elements in sub-components in a nested component. In this case, $refs can only get elements in direct subcomponents, but not elements in other subcomponents.

For this situation, we can use native dom operations to solve it. You can set a class or id in the component that needs to get the dom element, and then get the element through the native document.getElementById or document.getElementsByClassName. Although this method can solve the problem, because the native DOM operation is asynchronous, if the rendering of the element has not been completed before the current operation of the element, the desired result will not be obtained by performing the native operation at this time.

Secondly, we can also use Vue's nextTick function to solve this problem. Vue's nextTick function can execute the callback function in the next event polling queue after the execution of the synchronization code of the current task queue is completed. We can use the nextTick function in the function that obtains the dom element to ensure that after the current operation, the element has been rendered and we can obtain the correct result for the element.

To sum up, it is a common problem that uniapp has too many levels and cannot obtain dom. For this problem, we can use the $refs provided by uniapp to obtain the elements in the component, and we can also use native dom operations or Vue's nextTick function to solve it. No matter which method is used, we should pay attention to the maintainability and readability of the code during development to improve development efficiency and reduce maintenance costs.

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