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EternalViewPager

Android ViewPager with infinite/looping scroll

This library is a bit different original Viewpager how to use. You should specify a value based on the first value or the last value.

Usage

Layout xml

<com.star_zero.eternalviewpager.EternalViewPager
	android:id="@+id/viewpager"
	android:layout_width="match_parent"
	android:layout_height="match_parent" />

Adapter

Implement class that inherit EternalPagerAdapter

public class SimpleAdapter extends EternalPagerAdapter<Integer> {

    private static final int START = 0;
    private static final int END = 10;

    public SimpleAdapter(FragmentManager fragmentManager, Integer initialKey) {
        // Pass the FragmentManager and the initial value.
        super(fragmentManager, initialKey);
    }

    @NonNull
    @Override
    public Fragment getItem(Integer key) {
        // Create and return Fragment.
        return SimpleFragment.createInstance(key);
    }

    @Nullable
    @Override
    protected Integer getNextKey(@NonNull Integer last) {
        // Return the next value.
        // If return null, stop scrolling.
        if (last == END) {
            return null;
        }
        return last + 1;
    }

    @Nullable
    @Override
    protected Integer getPrevKey(@NonNull Integer first) {
        // Return the previous value.
        // If return null, stop scrolling.
        if (first == START) {
            return null;
        }
        return first - 1;
    }

    @Nullable
    @Override
    protected Bundle saveKeysState(@NonNull ArrayList<Integer> keys) {
        // Save current state.
        Bundle bundle = new Bundle();
        bundle.putIntegerArrayList("keys", keys);
        return bundle;
    }

    @Nullable
    @Override
    protected List<Integer> restoreKeysState(@NonNull Bundle bundle) {
        // Restore state.
        return bundle.getIntegerArrayList("keys");
    }
}

At getNextKey or getPrevKey, you should return the next or previous value of the method parameter. If you return null, stop scrolling.

Activity/Fragment

SimpleAdapter adapter = new SimpleAdapter(getSupportFragmentManager(), 0);
EternalViewPager viewpager = findViewById(R.id.viewpager);
viewpager.setAdapter(adapter);

For more usage, see sample.

Download

latest version:

implementation 'com.star_zero:eternalviewpager:<latest_version>'

Known Issues

• When scrolling continuously, it looks like reached last data. Then it can scroll again after a stop a moment. Because this library rearranges internal data when scrolling state is stopped.
• Using with TabLayout does not work fine. It's strange behavior when scrolling.

License

Copyright 2018 Kenji Abe

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.