adding next and previous buttons to ViewPager

Question

I want to make an image slider with Android Studio. I found a new slider code, built with ViewPager, I tried it and worked.. but I want to add 2 buttons for next and previous..

When clicked button, it must go to next picture or previous picture.

here the mainactivity,

package org.trial.slider;   
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.view.ViewPager;

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
        ImageAdapter adapter = new ImageAdapter(this);
        viewPager.setAdapter(adapter);  
     }          
}

ImageAdapter.java file,

    package org.trial.slider;

    import android.content.Context;
    import android.support.v4.view.PagerAdapter;
    import android.support.v4.view.ViewPager;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.Button;
    import android.widget.ImageView;

    /**
     * Created by ismail on 30.03.16.
     */
    public class ImageAdapter extends PagerAdapter {
        Context context;


        private int[] GalImages = new int[] {
                R.drawable.one,
                R.drawable.two,
                R.drawable.three
        };
        ImageAdapter(Context context){
            this.context=context;
        }
        @Override
        public int getCount() {
            return GalImages.length;
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == ((ImageView) object);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            ImageView imageView = new ImageView(context);
            int padding = context.getResources().getDimensionPixelSize(R.dimen.padding_medium);
            imageView.setPadding(padding, padding, padding, padding);
            imageView.setScaleType(ImageView.ScaleType.FIT_XY);
            imageView.setImageResource(GalImages[position]);
            ((ViewPager) container).addView(imageView, 0);
            return imageView;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            ((ViewPager) container).removeView((ImageView) object);
        }
    }

And I have 2 XML files; fragment_pager and swipe_fragment

score 4 · Answer 1 · edited Jun 11 '16 at 09:47

add button your MainActivity and activity_main.xml
add code button.setonclicklister(this); in OnCreate()

Example code here :

@Override
public void onClick(View v) {
    int id = v.getId();
    switch (id) {
        //prev button
        case R.id.btn_list_detail_img_prev:
            viewPager.setCurrentItem(mPager.getCurrentItem()-1,true);
            break;
        //nextbutton, 1st argument : pageindex, 2nd argument : Enable smooth 
        case R.id.btn_list_detail_img_next:
            viewPager.setCurrentItem(mPager.getCurrentItem()+1,true);
            break;
}

score 2 · Answer 2 · edited Mar 31 '16 at 05:04

2

There is a method name viewPager.setCurrentItem(position).
This method take a integer value as a index and is set on viewPager object using this method you can change the position if pager item.

edited Mar 31 '16 at 05:04

Suhas Bachewar

1,230
7
21

answered Mar 31 '16 at 04:58

Rohit Heera

2,709
2
21
31

how? can you explain? – İsmail Mar 31 '16 at 12:43
you need to add two button above view pager in your layout – Rohit Heera Mar 31 '16 at 12:49
and check the current position of viewpager in activity – Rohit Heera Mar 31 '16 at 12:50

score 0 · Answer 3 · edited Nov 15 '17 at 07:16

class MyClass extends Fragment implements ViewPager.OnPageChangeListener {

    private int selectedViewPager = 0;

    public void onViewClicked(View view) {

        switch (view.getId()) {
            case R.id.backward:
                if (selectedViewPager > 0) {
                    viewPager.setCurrentItem(selectedViewPager - 1, true);
                }
                break;

            case R.id.fwd:
                if (viewPager.getAdapter().getCount() > selectedViewPager) {
                    viewPager.setCurrentItem(selectedViewPager + 1, true);
                }
                break;
        }
    }


    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    @Override
    public void onPageSelected(int position) {
        selectedViewPager = position;
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
}

adding next and previous buttons to ViewPager

3 Answers3