Display ImageButton on last slide of viewpager - android-studio

Question

I'm trying to have a button appear only on the last page of a ViewPager. I have the working button but it is displayed on all the pages instead of only the last page. I want to have it visible only on the last page. Here is my code.
activity_welcome2.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
xmlns:android="http://schemas.android.com/apk/res/android"
tools:context=".Welcome_Activity"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.viewpager.widget.ViewPager
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!--- for dots -->
<View
android:id="#+id/view1"
android:layout_width="match_parent"
android:layout_height="1dp"
android:alpha=".5"
android:layout_above="#+id/dotsLayout"
android:background="#color/white"
android:layout_marginBottom="15dp" />
<LinearLayout
android:id="#+id/dotsLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_alignParentBottom="true"
android:orientation="horizontal"
android:gravity="center"
android:layout_marginBottom="55sp" />
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageButton
android:id="#+id/next3"
android:layout_width="99dp"
android:layout_height="45dp"
android:background="#android:color/transparent"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.822"
app:srcCompat="#drawable/next" />
</androidx.constraintlayout.widget.ConstraintLayout>
</RelativeLayout>
Welcome_Activity.java
package com.group7.salitongue;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.viewpager.widget.ViewPager;
public class Welcome_Activity extends AppCompatActivity {
private ViewPager mPager;
private int[] layouts = { R.layout.activity_main, R.layout.activity_splashscreen2, R.layout.activity_welcome };
private MpagerAdapter mpagerAdapter;
private LinearLayout Dots_Layout;
private ImageView[] dots;
private ImageButton nextBtn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welcome2);
mPager = (ViewPager) findViewById(R.id.viewPager);
mpagerAdapter = new MpagerAdapter(layouts, this);
mPager.setAdapter(mpagerAdapter);
Dots_Layout = (LinearLayout) findViewById(R.id.dotsLayout);
createDots(0);
mPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
#Override
public void onPageSelected(int position) {
createDots(position);
}
#Override
public void onPageScrollStateChanged(int state) {}
});
// transition button to Signup page
nextBtn = (ImageButton) findViewById(R.id.next3);
nextBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(Welcome_Activity.this,MainActivity.class);
startActivity(intent);
}
});
}
private void createDots(int current_position) {
if(Dots_Layout != null)
Dots_Layout.removeAllViews();
dots = new ImageView[layouts.length];
for (int i = 0; i < layouts.length; i++) {
dots[i] = new ImageView(this);
if (i == current_position) {
dots[i].setImageDrawable(ContextCompat.getDrawable(this, R.drawable.active_dots));
}
else {
dots[i].setImageDrawable(ContextCompat.getDrawable(this, R.drawable.default_dots));
}
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT
);
params.setMargins(4, 0, 4, 0);
Dots_Layout.addView(dots[i],params);
}
}
}
How can I display the button only when the user has reached the last page of swiping?

Answer 1

Just listen in the onPageSelected method of your OnPageChangeListener when the last page is reached and set the button to visible. In all other cases, just hide it.
#Override
public void onPageSelected(int position) {
createDots(position);
// only show the button when the last page is reached
if (position == mPagerAdapter.getCount() - 1)
nextBtn.setVisibility(View.VISIBLE);
else
nextBtn.setVisibility(View.GONE);
}