How does UniAPP define select?

UniAPP is a cross-platform development framework based on the Vue.js framework, which can be used to develop iOS, Android and H5 applications. Among them, select is one of the form components frequently used in UniAPP. In this article, we will explore how select is defined in UniAPP.

1. Select definition

In UniAPP, you can use the <Picker> tag to define a select component. For example:

<template>
  <view>
    <picker mode="selector" :range="{{ array }}" @change="bindPickerChange">
      <view class="picker">
        当前选择：{{ array[index] }}
      </view>
    </picker>
  </view>
</template>
<script>
  export default {
    data() {
      return {
        array: ['选项一', '选项二', '选项三', '选项四'],
        index: 0
      };
    },
    methods: {
      bindPickerChange(e) {
        console.log('选中值为', e.detail.value);
        this.index = e.detail.value;
      }
    }
  };
</script>

In this example, we use the <Picker> tag to define a select component. Among them, mode="selector" indicates that this is a select component in selector mode. The range attribute is used to define the option list of this select component. @changeThe event will trigger the corresponding callback function when the option changes. In the callback function, you can get the value of the currently selected option through e.detail.value. Save the value of the currently selected option (that is, an element in the array) by storing an index variable in data, and display the currently selected option by binding it to the text of the view.

2. Select-related attributes

In addition to defining a select component in the template, we can also control the behavior of this component through some attributes. Commonly used attributes include:

1. mode: select mode, which can be selector, multiSelector, time, date, region.
2. range: The option array of the select component, which can be a static array or a dynamically calculated value.
3. value: The default selected value of the select component.
4. disabled: Whether the select component is disabled.
5. start: The start time of the select component.
6. end: The end time of the select component.
7. fields: When mode is time or date, specify the fields to be displayed. It can be hour, minute, second, year, month, day.

3. Custom styles of select

In addition to defining the relevant attributes of select, we can also change the appearance of select through custom styles. Generally speaking, we can define the corresponding style in the <style> tag:

<style>
  .picker {
    font-size: 16px;
    color: #999;
    text-align: center;
    padding: 20px;
    margin-top: 10px;
    border: 1px solid #eee;
  }
</style>

In this example, we pass it as class="picker" The label sets some styles to change the appearance of the select. Among them, we added styles such as font size, text color, text position, and padding.

To sum up, we can flexibly define a select component through template definition, attribute settings and custom styles. I hope that through this article, readers can better understand and master the use of the select component in UniAPP.

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