Button View is not Visible even after setting its visibility true

Question

I am making a quiz app hence I wanted my MenuButton and NextButton view Invisible at the beginning but after satisfying a particular condition I wanted the View to be visible again hence I used findViewById(R.id.MenuButton).setVisibility(View.VISIBLE); and same for the NextButton but still these view were Invisible.What am I doing wrong?

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout

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:layout_gravity="center">

<TextView
    android:id="@+id/Question"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="46dp"
    android:text="TextView"
    android:gravity="center"
    android:textSize="25dp"
    android:textColor="#000000"/>

<RadioButton
    android:id="@+id/radioButton1"
    android:layout_width="wrap_content"
    android:layout_height="25dp"
    android:text="RadioButton1"
    android:textSize="20sp"
    android:textColor="#000000"
    android:layout_marginLeft="43dp"
    android:layout_marginStart="43dp"
    android:layout_marginTop="54dp"
    android:layout_below="@+id/Question"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:onClick="On_RadioButton1_Click"/>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/linearLayout"
    android:orientation="horizontal"
    android:layout_marginTop="55dp"
    android:layout_below="@+id/radioButton4"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true">

    <Button
        android:id="@+id/MenuButton"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_marginLeft="40dp"
        android:textSize="20dp"
        android:text="menu" />

    <Button
        android:id="@+id/NextButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:layout_marginLeft="125dp"
        android:text="next" />

</LinearLayout>

</RelativeLayout>

//Java file

private int Question_no=0;
private Boolean Boolean_Var=false;

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_question1);

    String[] Question_Array = getResources().getStringArray(R.array.Question1);
    TextView Questions = (TextView) findViewById(R.id.Question);
    Questions.setText(Question_Array[Question_no]);

    String[] Radio_Button1_Array = getResources().getStringArray(R.array.Option_1);
    RadioButton Radio_Button1 = (RadioButton) findViewById(R.id.radioButton1);
    Radio_Button1.setText(Radio_Button1_Array[Question_no]);

    findViewById(R.id.MenuButton).setVisibility(View.INVISIBLE);
    findViewById(R.id.NextButton).setVisibility(View.INVISIBLE);

}
public void On_RadioButton1_Click(View view)
{
    if(Boolean_Var==false)
    {
        String[] CorrectAns_Array = getResources().getStringArray(R.array.Answer1);
        String CorrectAns = CorrectAns_Array[Question_no];
        String[] Answer_Array = getResources().getStringArray(R.array.Option_1);
        String Answer = Answer_Array[Question_no];


        if(Answer.equals(CorrectAns))
        {
            RadioButton Right_Ans = (RadioButton) findViewById(R.id.radioButton1);
            Right_Ans.setTextColor(Color.GREEN);
            AnswerSubmitted();
        }
        else
        {
            RadioButton Wrong_Ans = (RadioButton) findViewById(R.id.radioButton1);
            Wrong_Ans.setTextColor(Color.RED);
            GreenTick();
            AnswerSubmitted();
         }
    }
    Boolean_Var=true;

}
 public void AnswerSubmitted()
{
    findViewById(R.id.MenuButton).setVisibility(View.VISIBLE);
    findViewById(R.id.NextButton).setVisibility(View.VISIBLE);
}

Answer 1

You should get a reference to your buttons and call setVisibility on the reference. What you're currently doing is setting visibility INVISIBLE on one reference and setting it VISIBLE on another.

Button nextButton;

//in onCreate
nextButton = (Button)findViewById(R.id.nextButton);
nextButton.setVisibility(View.INVISIBLE);

//in AnswerSubmitted
nextButton.setVisibility(View.VISIBLE);

Answer 2

I think you should tell android that you want to execute that method when your radiobutton is clicked. by adding :

    Radio_Button1.setOnClickListener(new OnClickListener (){
 public void onClick(View v) {
   On_RadioButton1_Click(v);
 }
});

So you can get that method executed everytime you click. Add it at the end of OnCreate