How uniapp implements data binding of input boxes

With the rapid development of mobile applications, cross-platform application development has become an increasingly popular choice, especially the uni-app cross-platform development framework, which allows developers to develop once using Vue syntax and then publish it. to multiple platforms, including iOS, Android, H5, mini programs, etc. In uni-app, how to implement data binding of input boxes? Next, let us take a look.

1. v-model instruction

In Vue, we can use the v-model instruction to perform two-way data binding between the input box and the properties in the Data object. This instruction is also applicable to uni -app framework.

The method of using the v-model directive is very simple. You only need to add the v-model directive on the <input> or <textarea> tag and specify the binding Just specify the properties of the Data object. For example:

<template>
  <view>
    <input type="text" v-model="inputValue"/>
    <view>输入的值为：{{inputValue}}</view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        inputValue: ''
      }
    }
  }
</script>

In the above example, we added the v-model="inputValue" directive on the <input> tag to align the input box with inputValueBind, so that the input value of the input box will be automatically updated to the inputValue attribute. At the same time, use {{inputValue}} interpolation syntax on the page to display the value of the input box.

2. @input event

In addition to the v-model directive, we can also use the @input event to bind input box data.

In the uni-app framework, you can use the @input event to monitor changes in the input value of the input box, and synchronize the changed value to the properties in the Data object, for example:

<template>
  <view>
    <input type="text" :value="inputValue" @input="handleInput"/>
    <view>输入的值为：{{inputValue}}</view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        inputValue: ''
      }
    },
    methods: {
      handleInput(e) {
        this.inputValue = e.target.value
      }
    }
  }
</script>

In the above example, we defined a value attribute on the <input> tag and bound it to the inputValue attribute of the Data object, At the same time, use the @input event to monitor the input value change of the input box, and synchronize the changed value to the inputValue attribute in the handleInput method. Similarly, use {{inputValue}} interpolation syntax on the page to display the value of the input box.

3. watch attribute

In addition to the v-model directive and @input event, we can also use the watch attribute of the component instance to monitor changes in attributes in the Data object and do something when the change occurs Take appropriate action.

In the uni-app framework, you can use the watch attribute to monitor property changes of the Data object, for example:

<template>
  <view>
    <input type="text" :value="inputValue"/>
    <view>输入的值为：{{inputValue}}</view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        inputValue: ''
      }
    },
    watch: {
      inputValue(newValue) {
        console.log('输入框的值变为：' + newValue)
      }
    }
  }
</script>

In the above example, we defined a watch attribute to monitor the Data object. The inputValue attribute, when its value changes, the console will output corresponding information.

Summary

In the uni-app framework, we can use a variety of methods to implement two-way data binding of input boxes, including v-model instructions, @input events and watch attributes. Different methods are suitable for different scenarios, and developers can choose the most appropriate method according to their own needs.

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