Random Films

STRINGS:
<resources>
    <string name="app_name">My Application</string>
    <string name="nextButton">NEXT</string>
    <string name="resetButton">RESET</string>
    <string-array name="movies">
        <item>Pretty Woman</item>
        <item>Iron Lady</item>
        <item>Hours</item>
        <item>August: Osage County</item>
        <item>Doubt</item>
    </string-array>
</resources>
MAIN ACTIVITY:
package com.itschoolsamsung.myapplication;

import android.content.res.Resources;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    String[] movies;
    boolean[] shown_movies;
    TextView tvTitle;
    int counter = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tvTitle = (TextView) findViewById(R.id.title);
        Resources r = getResources();
        movies = r.getStringArray(R.array.movies);
        shown_movies = new boolean[movies.length];
    }
    public void nextClick(View v){
        int k = 0;
        do{
        k = (int) (Math.random()*movies.length);
        } while(shown_movies[k] && counter<=movies.length);
        tvTitle.setText(movies[k]);
        shown_movies[k] = true;
        counter++;
    }
    public void resetClick(View v){
        shown_movies = new boolean[movies.length];
    }
}
ACTIVITY MAIN:
<?xml version="1.0" encoding="utf-8"?>
<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"
    android:orientation="vertical"
    tools:context="com.itschoolsamsung.myapplication.MainActivity">

    <TextView
        android:textSize="40sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/title"/>
    <Button
        android:textSize="40sp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/nextButton"
        android:onClick="nextClick"
        />
    <Button
        android:textSize="40sp"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:text="@string/resetButton"
        android:onClick="restClick"/>
</LinearLayout>