How to solve the problem of the upper left corner disappearing when uniapp jumps

Recently, many uniapp developers have encountered a strange problem: when jumping to a new page, the return button in the upper left corner will suddenly disappear, making the user unable to return to the previous page. Although this problem is annoying, it can be solved with some simple methods. In this article, we will introduce you in detail how to solve the problem of the upper left corner of the uniapp jump disappearing.

1. Check the page jump method

First, we need to check whether a necessary operation is missing when the page jumps. In uniapp, we can jump to different pages through navigateTo, redirectTo, switchTab, reLaunch, etc. Among them, when using the navigateTo or redirectTo method to jump, we must also carry the delta parameter, indicating how many pages to return.

For example:

uni.navigateTo({
url: '/pages/pageA/pageA?delta=1',
})

If we Jump to the pageA page, and the "Return" button needs to be displayed in the upper left corner of the pageA page, then we must set the delta value to 1 in the pageA page, and add the onLoad life cycle function:

onLoad: function (option) {
  this.delta = option.delta || 1;
}

Then in Add the following code to the onUnload life cycle function of pageA:

onUnload: function () {
  uni.navigateBack({
    delta: this.delta
  })
}

This way, the correct page can be returned when the user clicks the "Return" button in the upper left corner.

2. Check the page stack depth

Another common reason is that the page stack depth is too large. In uniapp, the page stack is a first-in, last-out (LIFO) data structure that is used to manage each page that users access in the mini program. If the page stack depth is too large, the system cannot correctly manage the pages in the stack, resulting in the return button of some pages not being displayed properly.

In order to solve this problem, we can use the uni.navigateBack function to clear some unnecessary pages and reduce the page stack depth to a manageable range. For example:

uni.navigateBack({
delta: 2
})

This will return to the third to last page in the page stack and at the same time replace the last two pages. Removed from the page stack. In this way, the problem of excessive page stack depth can be effectively solved.

3. Check the page style

The last reason is the page style problem. If we set some wrong CSS styles in the page, it may cause the page layout to be disordered, thus affecting the normal display of the return button in the upper left corner of the page.

In order to avoid this problem, we can follow the official style specifications provided by uniapp during the development process and try to use uniapp's built-in components and styles. At the same time, we should also actively debug the page style and use the developer tools of browsers such as Chrome to view the real layout of the page so that style problems can be fixed in a timely manner.

In short, there are many reasons for the problem of the disappearance of the upper left corner of the uniapp jump, but we only need to carefully check the code and find the reason, and we can easily solve this problem. I hope this article can help you avoid similar problems during the development process.

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