如何从React Native中的TextField获取值，由于空值而无法将数据存储到数据库

Question

I've been working on react native and laravel within 2 months, and so far so good. But I got stuck when I am trying to do post method in react native. I made a simple form with textfield from react native materials. I knew that the application is connected already with my back-end, but when I want to store data, it shown an error about the column should not be null even I already inserted values.

I already check the onChange and the value itself also the method that I declared to do post method. Here is my constructor, textfield, and the onPress for submit Button

Here is my Constructor:

constructor(){
        super();
        this.state = {
            Ketua: '',
        Level: '',
        }
    }

Here is the Textfield:

                <TextField
                    label = 'Ketua Kegiatan'
                    onChange={(data) => { this.setState({Ketua:data.target.value}) }}
                    value = {this.state.Ketua}
                />

                <TextField
                    label = 'Laboratorium'
                    onChange={(data) => { this.setState({lab:data.target.value}) }}
                    value = {this.state.lab}
                />

                <TextField
                    label = 'Level'
                    onChange={(data) => { this.setState({level:data.target.value}) }}
                    value = {this.state.level}
                />

Here is my Submit Method:

submit(){
        let url = "http:/IP:Localhost/api/pinjams";
        let data = this.state;
        fetch(url,{
            method:'POST',
            headers:{
                "Content-Type" : "application/json",
                "Accept" : "application/json"
            },
            body: JSON.stringify(data)
        })
        .then((result) => {
            result.json().then((resp) => {
                console.warn("resp", resp)
                alert("Data is Submitted")
            })
        })
    } 

And, here is my Submit Button

<Button
                    style={{fontSize:20, color:'orange'}}
                    styleDisabled={{color:'grey'}}
                    onPress={()=>{this.submit()}}
                    > {"\n"} Submit
                </Button>

But Here is The ERROR MESSAGE:

resp, Object {
  "exception": "Illuminate\\Database\\QueryException",
  "file": "C:\\xampp\\htdocs\\coba_api_laravel\\vendor\\laravel\\framework\\src\\Illuminate\\Database\\Connection.php",
  "line": 664,
  "message": "SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'ketua_kegiatan' cannot be null (SQL: insert into `tb_peminjaman_mhs` (`ketua_kegiatan`, `lab`, `level`) values (?, ?, ?))",

If anyone can help me to solve this error, I'd be so thankful for that :)

Answer 1

I figured out how to solve mine, i think it's because in the constructor state we need to arrange the variable row same as in database and also match the variable name in onChange with the columns in database. What I mean is try to match the variable that you are going to use with the column name in database. Thank You So much for helping me out !