Checkbox control in Android Application
In this article I am going to
explain how to create a checkbox control in android application by using
CheckBox widget. When the CheckBox is
pressed, toast message will indicate the current state of the checkbox and the
text of the checkbox will change.
Start a new project, named CheckBoxDemo.
Open res/layout/main.xml and add the
checkbox as shown below:
<?xml
version="1.0"
encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<CheckBox android:id="@+id/checkbox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Check me"/>
</LinearLayout>
Open the activity file and add the following code as given below:
import
android.app.Activity;
import
android.os.Bundle;
import
android.view.View;
import
android.view.View.OnClickListener;
import
android.widget.CheckBox;
import
android.widget.Toast;
public
class CheckBoxActivity
extends Activity {
@Override
public
void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final CheckBox checkbox=(CheckBox)findViewById(R.id.checkbox);
checkbox.setOnClickListener(new OnClickListener()
{
public
void onClick(View v) {
if(((CheckBox)v).isChecked())
{
Toast.makeText(CheckBoxActivity.this,
"Selected",
Toast.LENGTH_SHORT).show();
checkbox.setText("Unchecked me");
}
else
{
Toast.makeText(CheckBoxActivity.this,
"Not Selected",
Toast.LENGTH_SHORT).show();
checkbox.setText("Checked me");
}
}
});
}
}
This captures the
CheckBox element from the layout, and
then adds a
View.OnClickListener. The
View.OnClickListener must implement the
onClick(View) callback method, which defines the action to be
made when the checkbox is clicked. When clicked,
isChecked() is called to check the new state of the check box.
If it has been checked, then a
Toast displays the message "Selected" and change the checkbox
text to "Unchecked me, otherwise it
displays "Not selected" and change
the checkbox text to "Checked me".
Run an application
Your output is something like this:
When you checked the checkbox, a
toast display a message "Selected" and checkbox text will change into "Unchecked me".
Again, when you unchecked the
checkbox, a toast display a message "Not
Selected" and checkbox text will change into "Checked me".