Definition of Dialog
“A dialog is a small window that prompts the user to make a decision or enter additional information.”AlertDialog is composed of three regions:
1. Title defines the title of the AlertDialog.
2. Content area displays message or custom layout.
3. Action button is used to add one, two or three buttons on AlertDialog, but it does not allow more than three.
To build an AlertDialog window you have to instantiate an AlertDialog.Builder with its constructor.
AlertDialog.Builder dialog = new AlertDialog.Builder(this);
AndroidDialog class has following three standard methods to add positive, negative and cancel button.
| Methods | Description |
|---|---|
| setNegativeButton(CharSequence text, DialogInterface.OnClickListener listener) | This method sets a listener and it will be invoked when the negative button of the dialog is pressed. |
| setNeutralButton(CharSequence text, DialogInterface.OnClickListener listener) | This method sets a listener and it will be invoked when the neutral button of the dialog is pressed. |
| setPositiveButton(CharSequence text, Dialognterface.OnClickListener listener) | This method sets a listener and it will be invoked when the positive button of the dialog is pressed. |
Example : AlertDialog
File Name: activity_main.xml
<LinearLayoutxmlns: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:orientation = "vertical">
<Button
android:id="@+id/threeButtonDialog"
android:layout_width = "match_parent"
android:layout_height = "wrap_content"
android:layout_marginTop = "50dp"
android:text = "ThreeButtonDialog"
android:textSize = "30dp"/>
</LinearLayout>
File Name: MainActivity.java
public class MainActivity extends Activity implements OnClickListener
{
Button button1;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate (savedInstanceState);
setContentView (R.layout.activity_main);
button1 = (Button)findViewById(R.id.threeButtonDialog);
button1.setOnClickListener (this);
}
@Override
public void onClick(View v)
{
// TODO Auto-generated method stub
showThreeButtonDialog();
}
public void showThreeButtonDialog()
{
AlertDialog.Builder dialog = newAlertDialog.Builder(this);
dialog.setTitle("Save Confirm");
dialog.setMessage("Are You Sure to save");
dialog.setPositiveButton("OK",newDialogInterface.OnClickListener()
{
@Override
publicvoidonClick(DialogInterface dialog, int which)
{
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "You clicked on OK", Toast.LENGTH_SHORT).show();
}
});
dialog.setNegativeButton("NO", newDialogInterface.OnClickListener()
{
@Override
publicvoidonClick(DialogInterface dialog, int which)
{
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "You clicked on NO", Toast.LENGTH_SHORT).show();
}
});
dialog.setNeutralButton("Cancel", newDialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialog, int which)
{
// TODO Auto-generated method stub
Toast.makeText(getApplicationContext(), "You clicked on Cancel button", Toast.LENGTH_SHORT).show();
}
});
AlertDialog ad = dialog.create();
ad.show();
}
}
Output:
