Android - 在本地数据库中存储评级值、旋转器值

Question

I am new to android programming and I am trying out a small programming exercise involving database storage.

I have a simple page where there is a spinner element, rating bar. For each entry in the spinner I would like to select a rating against that entry and in the end when upload button is clicked, I want all the entries to be stored in database. So that when the app is opened again, the stored ratings are shown.

I have come up with the following design for the layout

ratingLayout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/button"
        android:layout_width="276dp"
        android:layout_height="60dp"
        android:layout_marginBottom="144dp"
        android:text="Upload Skills"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent" />

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="258dp"
        android:layout_height="64dp"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.452"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.54" />

    <RatingBar
        android:id="@+id/ratingBar2"
        android:layout_width="242dp"
        android:layout_height="51dp"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/spinner" />
</androidx.constraintlayout.widget.ConstraintLayout>

and the corresponding activity.java file is as follows

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

import androidx.appcompat.app.AppCompatActivity;

import java.util.ArrayList;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.ratingLayout);

        Spinner spinner = findViewById(R.id.spinner);
        ArrayList<String> arrayList = new ArrayList<>(Arrays.asList("Java", "C++", "C", "Python", "Ruby", "JavaScript"));
        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, arrayList);
        arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(arrayAdapter);
    }
}

Could someone let me know how to proceed forward with choosing the ratings and uploading all the ratings at once to the database?

Answer 1

Databases are a huge topic in Android, and we can't exactly cover all that goes into it in a single post. I'd suggest you use a Room database. See this codelab:

https://codelabs.developers.google.com/codelabs/android-room-with-a-view/#0