Android: Vertical ViewPager [closed]

android android-viewpager

Is there a way to make a ViewPager that does not scroll horizontally, but vertically?!


You can use a ViewPager.PageTransformer to give the illusion of a vertical ViewPager. To achieve scrolling with a vertical instead of a horizontal drag you will have to override ViewPager's default touch events and swap the coordinates of MotionEvents prior to handling them, e.g.:

/**
 * Uses a combination of a PageTransformer and swapping X & Y coordinates
 * of touch events to create the illusion of a vertically scrolling ViewPager. 
 * 
 * Requires API 11+
 * 
 */
public class VerticalViewPager extends ViewPager {

    public VerticalViewPager(Context context) {
        super(context);
        init();
    }

    public VerticalViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        // The majority of the magic happens here
        setPageTransformer(true, new VerticalPageTransformer());
        // The easiest way to get rid of the overscroll drawing that happens on the left and right
        setOverScrollMode(OVER_SCROLL_NEVER);
    }

    private class VerticalPageTransformer implements ViewPager.PageTransformer {

        @Override
        public void transformPage(View view, float position) {

            if (position < -1) { // [-Infinity,-1)
                // This page is way off-screen to the left.
                view.setAlpha(0);

            } else if (position <= 1) { // [-1,1]
                view.setAlpha(1);

                // Counteract the default slide transition
                view.setTranslationX(view.getWidth() * -position);

                //set Y position to swipe in from top
                float yPosition = position * view.getHeight();
                view.setTranslationY(yPosition);

            } else { // (1,+Infinity]
                // This page is way off-screen to the right.
                view.setAlpha(0);
            }
        }
    }

    /**
     * Swaps the X and Y coordinates of your touch event.
     */
    private MotionEvent swapXY(MotionEvent ev) {
        float width = getWidth();
        float height = getHeight();

        float newX = (ev.getY() / height) * width;
        float newY = (ev.getX() / width) * height;

        ev.setLocation(newX, newY);

        return ev;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev){
        boolean intercepted = super.onInterceptTouchEvent(swapXY(ev));
        swapXY(ev); // return touch coordinates to original reference frame for any child views
        return intercepted;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return super.onTouchEvent(swapXY(ev));
    }

}

Of course you can tweak these settings as you see fit. Ends up looking like this:

VerticalViewPager demo


Vertical ViewPager

The other answers here all seemed to have some problems with them. Even the recommended open source projects weren't merging recent pull requests with bug fixes. Then I found a VerticalViewPager from Google that they used some DeskClock app. I trust using Google's implementation a lot more than the other answers floating around here. (Google's version is similar to the current top-voted answer, but more thorough.)

Full Example

This example is almost exactly the same as my Basic ViewPager Example, with a few minor changes to make use of the VerticalViewPager class.

enter image description here

XML

Add the xml layouts for the main activity and for each page (fragment). Note that we use VerticalViewPager rather than the standard ViewPager. I'll include the code for that below.

activity_main.xml

<?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"
    tools:context="com.example.verticalviewpager.MainActivity">

    <com.example.myapp.VerticalViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

fragment_one.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" >

    <TextView
        android:id="@+id/textview"
        android:textSize="30sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />

</RelativeLayout>

Code

The code for the VerticalViewPager is not mine. It is just a stripped down version (without comments) from the Google source code. Check out that one for the most up to date version. The comments there are also helpful for understanding what is happening.

VerticalViewPager.java

import android.support.v4.view.ViewPager;    

public class VerticalViewPager extends ViewPager {

    public VerticalViewPager(Context context) {
        this(context, null);
    }

    public VerticalViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    @Override
    public boolean canScrollHorizontally(int direction) {
        return false;
    }

    @Override
    public boolean canScrollVertically(int direction) {
        return super.canScrollHorizontally(direction);
    }

    private void init() {
        setPageTransformer(true, new VerticalPageTransformer());
        setOverScrollMode(View.OVER_SCROLL_NEVER);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        final boolean toIntercept = super.onInterceptTouchEvent(flipXY(ev));
        flipXY(ev);
        return toIntercept;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        final boolean toHandle = super.onTouchEvent(flipXY(ev));
        flipXY(ev);
        return toHandle;
    }

    private MotionEvent flipXY(MotionEvent ev) {
        final float width = getWidth();
        final float height = getHeight();
        final float x = (ev.getY() / height) * width;
        final float y = (ev.getX() / width) * height;
        ev.setLocation(x, y);
        return ev;
    }

    private static final class VerticalPageTransformer implements ViewPager.PageTransformer {
        @Override
        public void transformPage(View view, float position) {
            final int pageWidth = view.getWidth();
            final int pageHeight = view.getHeight();
            if (position < -1) {
                view.setAlpha(0);
            } else if (position <= 1) {
                view.setAlpha(1);
                view.setTranslationX(pageWidth * -position);
                float yPosition = position * pageHeight;
                view.setTranslationY(yPosition);
            } else {
                view.setAlpha(0);
            }
        }
    }
}

MainActivity.java

I only swapped out VerticalViewPager for ViewPager.

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

public class MainActivity extends AppCompatActivity {

    static final int NUMBER_OF_PAGES = 2;

    MyAdapter mAdapter;
    VerticalViewPager mPager;

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

        mAdapter = new MyAdapter(getSupportFragmentManager());
        mPager = findViewById(R.id.viewpager);
        mPager.setAdapter(mAdapter);
    }

    public static class MyAdapter extends FragmentPagerAdapter {
        public MyAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public int getCount() {
            return NUMBER_OF_PAGES;
        }

        @Override
        public Fragment getItem(int position) {

            switch (position) {
                case 0:
                    return FragmentOne.newInstance(0, Color.WHITE);
                case 1:
                    // return a different Fragment class here
                    // if you want want a completely different layout
                    return FragmentOne.newInstance(1, Color.CYAN);
                default:
                    return null;
            }
        }
    }

    public static class FragmentOne extends Fragment {

        private static final String MY_NUM_KEY = "num";
        private static final String MY_COLOR_KEY = "color";

        private int mNum;
        private int mColor;

        // You can modify the parameters to pass in whatever you want
        static FragmentOne newInstance(int num, int color) {
            FragmentOne f = new FragmentOne();
            Bundle args = new Bundle();
            args.putInt(MY_NUM_KEY, num);
            args.putInt(MY_COLOR_KEY, color);
            f.setArguments(args);
            return f;
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            mNum = getArguments() != null ? getArguments().getInt(MY_NUM_KEY) : 0;
            mColor = getArguments() != null ? getArguments().getInt(MY_COLOR_KEY) : Color.BLACK;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View v = inflater.inflate(R.layout.fragment_one, container, false);
            v.setBackgroundColor(mColor);
            TextView textView = v.findViewById(R.id.textview);
            textView.setText("Page " + mNum);
            return v;
        }
    }
}

Finished

You should be able to run the app and see the result in the animation above.

See also

  • Basic ViewPager Example
  • ViewPager with FragmentPagerAdapter

I have a solution that works for me in two steps.

  1. onInstantiateItem() of PagerAdapter, create the view and rotate it by -90:

    view.setRotation(-90f)

    If you are using FragmentPagerAdapter, then:

    objFragment.getView().setRotation(-90)

  2. Rotate ViewPager view by 90 degree:

    objViewPager.setRotation(90)

Works like a charm at least for my requirement.


For someone who is struggling with how to make vertical ViewPager works inside horizontal, just do following stuff:

Vertical ViewPager

public class VerticalViewPager extends ViewPager {
    public VerticalViewPager(Context context) {
        super(context);
        init();
    }

    public VerticalViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        setPageTransformer(true, new VerticalPageTransformer());
        setOverScrollMode(OVER_SCROLL_NEVER);
    }

    private class VerticalPageTransformer implements ViewPager.PageTransformer {

        @Override
        public void transformPage(View view, float position) {

            if (position < -1) {
                view.setAlpha(0);
            } else if (position <= 1) {
                view.setAlpha(1);

                view.setTranslationX(view.getWidth() * -position);

                float yPosition = position * view.getHeight();
                view.setTranslationY(yPosition);
            } else {
                view.setAlpha(0);
            }
        }
    }

    private MotionEvent swapXY(MotionEvent ev) {
        float width = getWidth();
        float height = getHeight();

        float newX = (ev.getY() / height) * width;
        float newY = (ev.getX() / width) * height;

        ev.setLocation(newX, newY);

        return ev;
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        boolean intercepted = super.onInterceptTouchEvent(swapXY(ev));
        swapXY(ev);
        return intercepted;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return super.onTouchEvent(swapXY(ev));
    }

}

Horizontal ViewPager

public class HorizontalViewPager extends ViewPager {
    private GestureDetector xScrollDetector;

    public HorizontalViewPager(Context context) {
        super(context);
    }

    public HorizontalViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        xScrollDetector = new GestureDetector(getContext(), new XScrollDetector());
    }

    class XScrollDetector extends GestureDetector.SimpleOnGestureListener {
        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            return Math.abs(distanceX) > Math.abs(distanceY);
        }
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        if (xScrollDetector.onTouchEvent(ev)) {
            super.onInterceptTouchEvent(ev);
            return true;
        }

        return super.onInterceptTouchEvent(ev);
    }

}

A slight extension this answer helped me to achieve my requirement (Vertical View Pager to animate similar like in Inshorts - News in 60 words)

public class VerticalViewPager extends ViewPager {

public VerticalViewPager(Context context) {
    super(context);
    init();
}

public VerticalViewPager(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
}

private void init() {
    // The majority of the magic happens here
    setPageTransformer(true, new VerticalPageTransformer());
    // The easiest way to get rid of the overscroll drawing that happens on the left and right
    setOverScrollMode(OVER_SCROLL_NEVER);
}

private class VerticalPageTransformer implements ViewPager.PageTransformer {
 private static final float MIN_SCALE = 0.75f;
    @Override
    public void transformPage(View view, float position) {

        if (position < -1) { // [-Infinity,-1)
            // This page is way off-screen to the left.
            view.setAlpha(0);

        }  else if (position <= 0) { // [-1,0]
            // Use the default slide transition when moving to the left page
            view.setAlpha(1);
            // Counteract the default slide transition
            view.setTranslationX(view.getWidth() * -position);

            //set Y position to swipe in from top
            float yPosition = position * view.getHeight();
            view.setTranslationY(yPosition);
            view.setScaleX(1);
            view.setScaleY(1);

        } else if (position <= 1) { // [0,1]
            view.setAlpha(1);

            // Counteract the default slide transition
            view.setTranslationX(view.getWidth() * -position);


            // Scale the page down (between MIN_SCALE and 1)
            float scaleFactor = MIN_SCALE
                    + (1 - MIN_SCALE) * (1 - Math.abs(position));
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);

        } else { // (1,+Infinity]
            // This page is way off-screen to the right.
            view.setAlpha(0);
        }

    }

}

/**
 * Swaps the X and Y coordinates of your touch event.
 */
private MotionEvent swapXY(MotionEvent ev) {
    float width = getWidth();
    float height = getHeight();

    float newX = (ev.getY() / height) * width;
    float newY = (ev.getX() / width) * height;

    ev.setLocation(newX, newY);

    return ev;
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev){
    boolean intercepted = super.onInterceptTouchEvent(swapXY(ev));
    swapXY(ev); // return touch coordinates to original reference frame for any child views
    return intercepted;
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
    return super.onTouchEvent(swapXY(ev));
}
}

I hope this might be helpful to someone else.

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