Background

HTML element has built-in form component , but no corresponding part for react-native. So, we have to do some additional work wrapping some basic component to create a form component. Then, some of excellent third part form components won the developers’ star in reactjs community. One of the best is tcomb-form-native . Today, we’ll use this component to create a simple form, and display it in a popup modal.

Snippets

install the form component module is just as simple as the below command:

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$ npm install tcomb-form-native --save

after installation, the two module included in package.json:

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"redux-persist": "^5.9.1",
"tcomb-form-native": "^0.6.11"

In the Example section of the tcomb-form-native README.md, it use require function to reference the library, but we can also use ES6 import for uniformity to other basic react-native component import.

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// var t = require('tcomb-form-native');
import t from 'tcomb-form-native';

After that, we have a Form Class from the t:

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const Form = t.form.Form;

Now, we are ready to create a real Form instance by combining three parts:

  • domain model, a struct to define your form fields;
  • form options, an object to define the relevant visual/invisible attributes about fields;
  • Form tag, the visual part returned in render function;

the complete implementation code like this:

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var Card = t.struct({
  big: t.String,              // a required string
  title: t.maybe(t.String),  // an optional string
  subtitle: t.maybe(t.String),  // an optional string
  // age: t.Number,               // a required number
});

var options = {
  fields: {
    big: {
      label: '词汇', // <= label for the name field
      placeholder: '填写你要记忆的词汇'
    },
    title: {
      label: '解释',
      placeholder: '填写对该词汇的解释'
    },
    subtitle: {
      label: '举例',
      placeholder: '对该词汇造句或者相关词汇'
    }
  }
}; // optional rendering options (see documentation)

...

<Form
  ref="form"
  type={Card}
  options={options}
  value={this.state.value}
/>

...

what does it look like? here it is:

the end result of the component source code is in here!

next post we’ll figure out how to dynamically create a popup form rather than defined in the root view of app component.

coming soon…