Android number picker dialog

dialog_picker.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	android:layout_marginBottom="4dp"
	android:layout_marginLeft="4dp"
	android:layout_marginRight="4dp"
	android:layout_marginTop="16dp"
	android:orientation="vertical">

	<NumberPicker
		android:id="@+id/picker"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_centerHorizontal="true"/>

</RelativeLayout>

showPickerDialog.java

	private void showPickerDialog() {
		AlertDialog.Builder builder = new AlertDialog.Builder(this);
		final View view = this.getLayoutInflater().inflate(R.layout.dialog_picker, null);
		builder.setView(view);
		//builder.setTitle();
		final NumberPicker picker = (NumberPicker) view.findViewById(R.id.picker);
		//picker.setMinValue();
		//picker.setMaxValue();
		//picker.setValue();
		builder.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
			@Override
			public void onClick(DialogInterface dialog, int id) {
				//positive button action

			}
		})
				.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int id) {
						//negative button action
					}
				});
		builder.create().show();
	}