Working with CheckBox in Android

Hello guys, how are you today? Its super Saturday, i hope you guys will be enjoying your weekend.

In this blog we are going to see how to work with the checkboxes in android. So lets get started.

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1) First of all  create an Android Application Project.

2) Go to "res/layout/activity_main.xml" and create 4 checkboxes thereselect, android, windows, ios. The code looks like

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:orientation="vertical" >
    
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Select all"
        android:id="@+id/select" />

    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Android"
        android:id="@+id/android" />
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Windows"
        android:id="@+id/win" />
    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="iOS"
        android:id="@+id/ios" />
    

</LinearLayout>

3) Next go to "src/your_package_name/MainActivity.java" and here we will implement OnCheckedChangeListener for all the checkboxes. On clicking the "select all" checkbox all the rest checkboxes should get selected and on unselecting it the rest should get unselected.

The code for MainActivity is given below

import android.app.Activity;
import android.os.Bundle;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Toast;

public class MainActivity extends Activity implements OnCheckedChangeListener {
    CheckBox select, android, win, ios;

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

        select = (CheckBox) findViewById(R.id.select);
        android = (CheckBox) findViewById(R.id.android);
        win = (CheckBox) findViewById(R.id.win);
        ios = (CheckBox) findViewById(R.id.ios);

        select.setOnCheckedChangeListener(this);
        android.setOnCheckedChangeListener(this);
        win.setOnCheckedChangeListener(this);
        ios.setOnCheckedChangeListener(this);
    }

    @Override
    public void onCheckedChanged(CompoundButton arg0, boolean arg1) {
        // TODO Auto-generated method stub
        switch (arg0.getId()) {
        case R.id.select:
            if (select.isChecked())
                select_all();
            else
                unselect_all();
            break;

        case R.id.android:
            if (android.isChecked())
                Toast.makeText(this, "Android is selected", Toast.LENGTH_SHORT)
                        .show();
            else
                Toast.makeText(this, "Android is unselected",
                        Toast.LENGTH_SHORT).show();
            break;

        case R.id.win:
            if (win.isChecked())
                Toast.makeText(this, "Windows is selected", Toast.LENGTH_SHORT)
                        .show();
            else
                Toast.makeText(this, "Windows is unselected",
                        Toast.LENGTH_SHORT).show();
            break;

        case R.id.ios:
            if (ios.isChecked())
                Toast.makeText(this, "ios is selected", Toast.LENGTH_SHORT)
                        .show();
            else
                Toast.makeText(this, "ios is unselected", Toast.LENGTH_SHORT)
                        .show();
            break;
        }
    }

    private void select_all() {
        // TODO Auto-generated method stub
        android.setChecked(true);
        win.setChecked(true);
        ios.setChecked(true);
    }

    private void unselect_all() {
        // TODO Auto-generated method stub
        android.setChecked(false);
        win.setChecked(false);
        ios.setChecked(false);
    }

}

Now we are done. Post your questions in the comment. I will be happy to answer those.

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Thank you