How to set the width and height of uniapp

With the popularity of mobile applications, more and more developers are beginning to use uniapp to quickly develop cross-platform mobile applications. For beginners of uniapp, there may be some confusion about its width and height settings. This article will introduce the relevant knowledge of uniapp's width and height settings to help everyone better master uniapp development skills.

1. Pixel unit

Before introducing the width and height settings of uniapp, we need to understand the pixel unit first. A pixel is a basic unit used in display devices that represents a point on the screen. On mobile devices, a pixel is often referred to as a physical pixel, which represents an actual point on the device's screen.

However, it should be noted that different devices have different pixel densities, so they display different numbers of pixels on the same size screen. Taking the iPhone 6 as an example, its screen resolution is 750x1334 pixels, and its pixel density (that is, the number of physical pixels contained per inch) is 326. So, there are 326 pixels per inch of screen on the iPhone 6.

2. Unit conversion

In uniapp, width and height settings need to be expressed in specific units. Commonly used units include pixels (px), percentages (%), viewport width units (vw), and viewport height units (vh). Among them, pixel (px) is the most commonly used unit.

However, it should be noted that different devices have different pixel densities, so on different devices, the same width and height settings may produce different effects. In order to solve this problem, you can use flexible layout (Flex layout) and relative units (rem) to adapt to different device screens.

In uniapp, 1rem is equal to the ratio of 750px divided by the device width. For example, if the width of a certain device is 375px, the size of 1rem is 375/750=0.5px.

3. Width and height settings

In uniapp, you can use the style attribute to set the width and height of a component. For example:

<view style="width:200px;height:150px;"></view>

In the above example, we use the style attribute to set the width to 200px and the height to 150px for a view component. This method is the simplest and crudest and can meet some simple layout needs.

However, using fixed width and height settings may produce different effects on different devices. Therefore, you can use percentages (%) or viewport units (vw, vh) to adapt to the screens of different devices.

Percent (%) is calculated relative to the width and height of the parent component and can be used for responsive layout. For example:

<view style="width:50%;height:50%;"></view>

In the above example, we use styles to set the width and height of a view component to 50% of the parent component.

Viewport units (vw, vh) can be used to adapt according to the screen size of the device. For example, the following code sets the width and height of a view component to 50% of the device width and height:

<view style="width:50vw;height:50vh;"></view>

In addition to fixed-size width and height settings, we can also use flexible layout (Flex layout). layout. Using Flex layout allows components to allocate width and height according to a certain ratio to adapt to different device screens.

4. Summary

In uniapp, there are many ways to set width and height, including pixel unit (px), percentage (%), viewport width unit (vw) and viewport Height unit (vh), etc. Different width and height setting methods are suitable for different scenarios and can be selected according to needs. At the same time, in order to adapt to the screens of different devices, you can use techniques such as flexible layout (Flex layout) and relative units (rem). Through these methods, uniapp applications can achieve good display effects on different devices.

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