TabLayout with viewpager not smooth scrolling

Question

Edit

I have followed these tutorials to fix this problem.

http://www.truiton.com/2015/06/android-tabs-example-fragments-viewpager/ https://g

Answer 1

First of all, to make all smooth don't do heavy operations on main thread, use async tasks (don't touch views in async task), and all will be smooth in anyway :)

Try my way to do this:

SlidingTabLayout:

public class SlidingTabLayout extends HorizontalScrollView {
    /**
     * Allows complete control over the colors drawn in the tab layout. Set with
     * {@link #setCustomTabColorizer(TabColorizer)}.
     */
    View oldSelection = null;

    public interface TabColorizer {

        /**
         * @return return the color of the indicator used when {@code position} is selected.
         */
        int getIndicatorColor(int position);

    }

    private static final int TITLE_OFFSET_DIPS = 24;
    private static final int TAB_VIEW_PADDING_DIPS = 8;
    private static final int TAB_VIEW_TEXT_SIZE_SP = 12;

    private int mTitleOffset;

    private int mTabViewLayoutId;
    private int mTabViewTextViewId;
    private boolean mDistributeEvenly;

    private ViewPager mViewPager;
    private SparseArray mContentDescriptions = new SparseArray();
    private ViewPager.OnPageChangeListener mViewPagerPageChangeListener;

    private final SlidingTabStrip mTabStrip;

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

    public SlidingTabLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        // Disable the Scroll Bar
        setHorizontalScrollBarEnabled(false);
        // Make sure that the Tab Strips fills this View
        setFillViewport(true);

        mTitleOffset = (int) (TITLE_OFFSET_DIPS * getResources().getDisplayMetrics().density);

        mTabStrip = new SlidingTabStrip(context);
        addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    }


    public void hideTab(int tabIndex){
        for (int i = 0; i < mTabStrip.getChildCount(); i++) {
            if(i == tabIndex){
                ((TextView)mTabStrip.getChildAt(i)).setVisibility(GONE);
            }
        }


    }

    /**
     * Set the custom {@link TabColorizer} to be used.
     *
     * If you only require simple custmisation then you can use
     * {@link #setSelectedIndicatorColors(int...)} to achieve
     * similar effects.
     */
    public void setCustomTabColorizer(TabColorizer tabColorizer) {
        mTabStrip.setCustomTabColorizer(tabColorizer);
    }

    public void setDistributeEvenly(boolean distributeEvenly) {
        mDistributeEvenly = distributeEvenly;
    }

    /**
     * Sets the colors to be used for indicating the selected tab. These colors are treated as a
     * circular array. Providing one color will mean that all tabs are indicated with the same color.
     */
    public void setSelectedIndicatorColors(int... colors) {
        mTabStrip.setSelectedIndicatorColors(colors);
    }

    /**
     * Set the {@link ViewPager.OnPageChangeListener}. When using {@link SlidingTabLayout} you are
     * required to set any {@link ViewPager.OnPageChangeListener} through this method. This is so
     * that the layout can update it's scroll position correctly.
     *
     * @see ViewPager#setOnPageChangeListener(ViewPager.OnPageChangeListener)
     */
    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
        mViewPagerPageChangeListener = listener;
    }

    /**
     * Set the custom layout to be inflated for the tab views.
     *
     * @param layoutResId Layout id to be inflated
     * @param textViewId id of the {@link TextView} in the inflated view
     */
    public void setCustomTabView(int layoutResId, int textViewId) {
        mTabViewLayoutId = layoutResId;
        mTabViewTextViewId = textViewId;
    }

    /**
     * Sets the associated view pager. Note that the assumption here is that the pager content
     * (number of tabs and tab titles) does not change after this call has been made.
     */
    public void setViewPager(ViewPager viewPager) {
        mTabStrip.removeAllViews();

        mViewPager = viewPager;
        if (viewPager != null) {
            viewPager.setOnPageChangeListener(new InternalViewPagerListener());
            populateTabStrip();
        }
    }

    /**
     * Create a default view to be used for tabs. This is called if a custom tab view is not set via
     * {@link #setCustomTabView(int, int)}.
     */
    protected TextView createDefaultTabView(Context context) {
        TextView textView = new TextView(context);
        textView.setGravity(Gravity.CENTER);
        textView.setTextSize(16);
        textView.setTypeface(Constants.TYPE_FACE_FONT_MEDIUM);
        textView.setLayoutParams(new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));

        TypedValue outValue = new TypedValue();
        getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground,
                outValue, true);
        textView.setBackgroundResource(outValue.resourceId);
        if(Constants.PRODUCT_DETAILS_TAB_BAR_STYLE == 2) {
            textView.setBackgroundColor(getResources().getColor(R.color.tab_bar_color));
            mTabStrip.setBackgroundColor(getResources().getColor(R.color.tab_bar_color));
        }

        textView.setAllCaps(true);

        int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density);
        textView.setPadding(padding, padding, padding, padding);

        return textView;
    }

    private void populateTabStrip() {
        removeOldSelection();
        oldSelection = null;
        final PagerAdapter adapter = mViewPager.getAdapter();
        final View.OnClickListener tabClickListener = new TabClickListener();

        for (int i = 0; i < adapter.getCount(); i++) {
            View tabView = null;
            TextView tabTitleView = null;

            if (mTabViewLayoutId != 0) {
                // If there is a custom tab view layout id set, try and inflate it
                tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip,
                        false);
                tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
            }

            if (tabView == null) {
                tabView = createDefaultTabView(getContext());
            }

            if (tabTitleView == null && TextView.class.isInstance(tabView)) {
                tabTitleView = (TextView) tabView;
            }

            if (mDistributeEvenly) {
                LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView.getLayoutParams();
                lp.width = 0;
                lp.weight = 1;
            }

            tabTitleView.setText(adapter.getPageTitle(i));

            tabView.setOnClickListener(tabClickListener);
            String desc = mContentDescriptions.get(i, null);
            if (desc != null) {
                tabView.setContentDescription(desc);
            }

            mTabStrip.addView(tabView);
            if(Constants.PRODUCT_DETAILS_TAB_BAR_STYLE == 1)
                tabTitleView.setTextColor(getResources().getColorStateList(R.color.primary_ultralight));
            else
                tabTitleView.setTextColor(getResources().getColor(R.color.primary_text));
            if (i == mViewPager.getCurrentItem()) {
                tabView.setSelected(true);
                tabTitleView.setTextColor(getResources().getColorStateList(R.color.primary_ultralight));
            }

        }

    }

    public void setContentDescription(int i, String desc) {
        mContentDescriptions.put(i, desc);
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        if (mViewPager != null) {
            scrollToTab(mViewPager.getCurrentItem(), 0);
        }
    }

    private void scrollToTab(int tabIndex, int positionOffset) {
        final int tabStripChildCount = mTabStrip.getChildCount();
        if (tabStripChildCount == 0 || tabIndex < 0 || tabIndex >= tabStripChildCount) {
            return;
        }

        View selectedChild = mTabStrip.getChildAt(tabIndex);
        if (selectedChild != null) {

            if(positionOffset == 0 && selectedChild != oldSelection) { // added part
                selectedChild.setSelected(true);
                removeOldSelection();
                oldSelection = selectedChild;
            }

            int targetScrollX = selectedChild.getLeft() + positionOffset;

            if (tabIndex > 0 || positionOffset > 0) {
                // If we're not at the first child and are mid-scroll, make sure we obey the offset
                targetScrollX -= mTitleOffset;
            }

            scrollTo(targetScrollX, 0);
        }
    }

    private class InternalViewPagerListener implements ViewPager.OnPageChangeListener {
        private int mScrollState;

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            int tabStripChildCount = mTabStrip.getChildCount();
            if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
                return;
            }

            mTabStrip.onViewPagerPageChanged(position, positionOffset);

            View selectedTitle = mTabStrip.getChildAt(position);
            int extraOffset = (selectedTitle != null)
                    ? (int) (positionOffset * selectedTitle.getWidth())
                    : 0;
            scrollToTab(position, extraOffset);

            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageScrolled(position, positionOffset,
                        positionOffsetPixels);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            mScrollState = state;

            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageScrollStateChanged(state);
            }
        }

        @Override
        public void onPageSelected(int position) {
            if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
                mTabStrip.onViewPagerPageChanged(position, 0f);
                scrollToTab(position, 0);
            }
            for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                mTabStrip.getChildAt(i).setSelected(position == i);

                if(Constants.PRODUCT_DETAILS_TAB_BAR_STYLE == 2){
                    if(position == i)
                        ((TextView)mTabStrip.getChildAt(i)).setTextColor(getResources().getColorStateList(R.color.primary_ultralight));
                    else
                        ((TextView)mTabStrip.getChildAt(i)).setTextColor(getResources().getColor(R.color.primary_text));
                }




            }
            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageSelected(position);
            }
        }

    }
    private void removeOldSelection() {
        if(oldSelection != null) {
            oldSelection.setSelected(false);
        }
    }
    private class TabClickListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {
            for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                if (v == mTabStrip.getChildAt(i)) {
                    mViewPager.setCurrentItem(i);
                    return;
                }
            }
        }
    }

}

SlidingTabStrip:

class SlidingTabStrip extends LinearLayout {

    private static final int DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS = 0;
    private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26;
    private static final int SELECTED_INDICATOR_THICKNESS_DIPS = 3;
    private static final int DEFAULT_SELECTED_INDICATOR_COLOR = 0xFF33B5E5;

    private final int mBottomBorderThickness;
    private final Paint mBottomBorderPaint;

    private final int mSelectedIndicatorThickness;
    private final Paint mSelectedIndicatorPaint;

    private final int mDefaultBottomBorderColor;

    private int mSelectedPosition;
    private float mSelectionOffset;

    private SlidingTabLayout.TabColorizer mCustomTabColorizer;
    private final SimpleTabColorizer mDefaultTabColorizer;

    SlidingTabStrip(Context context) {
        this(context, null);
    }

    SlidingTabStrip(Context context, AttributeSet attrs) {
        super(context, attrs);
        setWillNotDraw(false);

        final float density = getResources().getDisplayMetrics().density;

        TypedValue outValue = new TypedValue();
        context.getTheme().resolveAttribute(android.R.attr.colorForeground, outValue, true);
        final int themeForegroundColor =  outValue.data;

        mDefaultBottomBorderColor = setColorAlpha(themeForegroundColor,
                DEFAULT_BOTTOM_BORDER_COLOR_ALPHA);

        mDefaultTabColorizer = new SimpleTabColorizer();
        mDefaultTabColorizer.setIndicatorColors(DEFAULT_SELECTED_INDICATOR_COLOR);

        mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS * density);
        mBottomBorderPaint = new Paint();
        mBottomBorderPaint.setColor(mDefaultBottomBorderColor);

        mSelectedIndicatorThickness = (int) (SELECTED_INDICATOR_THICKNESS_DIPS * density);
        mSelectedIndicatorPaint = new Paint();
    }

    void setCustomTabColorizer(SlidingTabLayout.TabColorizer customTabColorizer) {
        mCustomTabColorizer = customTabColorizer;
        invalidate();
    }

    void setSelectedIndicatorColors(int... colors) {
        // Make sure that the custom colorizer is removed
        mCustomTabColorizer = null;
        mDefaultTabColorizer.setIndicatorColors(colors);
        invalidate();
    }

    void onViewPagerPageChanged(int position, float positionOffset) {
        mSelectedPosition = position;
        mSelectionOffset = positionOffset;
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        final int height = getHeight();
        final int childCount = getChildCount();
        final SlidingTabLayout.TabColorizer tabColorizer = mCustomTabColorizer != null
                ? mCustomTabColorizer
                : mDefaultTabColorizer;

        // Thick colored underline below the current selection
        if (childCount > 0) {
            View selectedTitle = getChildAt(mSelectedPosition);
            int left = selectedTitle.getLeft();
            int right = selectedTitle.getRight();
            int color = tabColorizer.getIndicatorColor(mSelectedPosition);

            if (mSelectionOffset > 0f && mSelectedPosition < (getChildCount() - 1)) {
                int nextColor = tabColorizer.getIndicatorColor(mSelectedPosition + 1);
                if (color != nextColor) {
                    color = blendColors(nextColor, color, mSelectionOffset);
                }

                // Draw the selection partway between the tabs
                View nextTitle = getChildAt(mSelectedPosition + 1);
                left = (int) (mSelectionOffset * nextTitle.getLeft() +
                        (1.0f - mSelectionOffset) * left);
                right = (int) (mSelectionOffset * nextTitle.getRight() +
                        (1.0f - mSelectionOffset) * right);
            }

            mSelectedIndicatorPaint.setColor(color);

            canvas.drawRect(left, height - mSelectedIndicatorThickness, right,
                    height, mSelectedIndicatorPaint);
        }

        // Thin underline along the entire bottom edge
        canvas.drawRect(0, height - mBottomBorderThickness, getWidth(), height, mBottomBorderPaint);
    }

    /**
     * Set the alpha value of the {@code color} to be the given {@code alpha} value.
     */
    private static int setColorAlpha(int color, byte alpha) {
        return Color.argb(alpha, Color.red(color), Color.green(color), Color.blue(color));
    }

    /**
     * Blend {@code color1} and {@code color2} using the given ratio.
     *
     * @param ratio of which to blend. 1.0 will return {@code color1}, 0.5 will give an even blend,
     *              0.0 will return {@code color2}.
     */
    private static int blendColors(int color1, int color2, float ratio) {
        final float inverseRation = 1f - ratio;
        float r = (Color.red(color1) * ratio) + (Color.red(color2) * inverseRation);
        float g = (Color.green(color1) * ratio) + (Color.green(color2) * inverseRation);
        float b = (Color.blue(color1) * ratio) + (Color.blue(color2) * inverseRation);
        return Color.rgb((int) r, (int) g, (int) b);
    }

    private static class SimpleTabColorizer implements SlidingTabLayout.TabColorizer {
        private int[] mIndicatorColors;

        @Override
        public final int getIndicatorColor(int position) {
            return mIndicatorColors[position % mIndicatorColors.length];
        }

        void setIndicatorColors(int... colors) {
            mIndicatorColors = colors;
        }
    }
}

And how to use:

Toolbar as appbar:

In Activity:

class DetailsTabsAdaptor extends FragmentPagerAdapter {
        String [] tabsTitlesPrepare = {getString(R.string.details),getString(R.string.features), getString(R.string.spects), getString(R.string.downloads)};
        List tabsTitles = new ArrayList<>();
        int tabsCount = 0;
        boolean featuresExist = false;
        boolean specificationsExist = false;
        boolean downloadsExist = false;

        public DetailsTabsAdaptor(FragmentManager fm) {
            super(fm);
            tabsTitles.add(tabsTitlesPrepare[0]);
            tabsCount++;
            if ((mProductDetails.ProductStructure.Features != null && mProductDetails.ProductStructure.Features.size()>0)) {
                tabsTitles.add(tabsTitlesPrepare[1]);
                featuresExist = true;
                tabsCount++;
            }
            if ((mProductDetails.ProductStructure.SpecificationBlocks != null && mProductDetails.ProductStructure.SpecificationBlocks.size()>0)) {
                tabsTitles.add(tabsTitlesPrepare[2]);
                specificationsExist = true;
                tabsCount++;
            }
            if ((mProductDetails.ProductStructure.SupportFiles != null && mProductDetails.ProductStructure.SupportFiles.size()>0)) {
                tabsTitles.add(tabsTitlesPrepare[3]);
                downloadsExist = true;
                tabsCount++;
            }

        }

        @Override
        public CharSequence getPageTitle(int position) {
            return tabsTitles.get(position);
        }

        @Override
        public Fragment getItem(int position) {
            if(position == 0){
                ProductDetailsFragment fragment = new ProductDetailsFragment();
                return fragment;
            }
            if(position == 1 && featuresExist){
                ProductFeaturesFragment fragment = new ProductFeaturesFragment();
                return fragment;
            }
            if((position == 2 && specificationsExist) || (position == 1 && (!featuresExist) && specificationsExist)){
                ProductSpectsFragment fragment = new ProductSpectsFragment();
                return fragment;
            }
            if((position == 3 && downloadsExist) || (position == 1 && (!featuresExist) && (!specificationsExist) && downloadsExist ) ||
                    (position == 2 && (!specificationsExist) && downloadsExist )){
                ProductDownloadsFragment fragment = new ProductDownloadsFragment();
                return fragment;
            }

            return null;
        }

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

And Setup Tabs

public void setupTabs() {
        mDetailsPager.setAdapter(new DetailsTabsAdaptor(getSupportFragmentManager()));
        mDetailsTabs.setViewPager(mDetailsPager);
        mDetailsTabs.setBackgroundResource(R.color.primary);
        mDetailsTabs.setCustomTabView(R.layout.custom_details_view_tab_layout, R.id.tabText);
        mDetailsTabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                return getResources().getColor(R.color.primary_light);
            }
        });


        mDetailsTabs.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            }

            @Override
            public void onPageSelected(int position) {

                for (int i = 0; i < mDetailsTabs.getChildCount(); i++)
                    mDetailsTabs.getChildAt(i).setSelected(i == position);
                if (position == DESCRIPTION_PAGE_ID)
                    mFavoritesButton.setVisibility(View.VISIBLE);
                else
                    mFavoritesButton.setVisibility(View.GONE);

            }

            @Override
            public void onPageScrollStateChanged(int state) {
            }
        });

    }

custom_details_view_tab_layout :

Final notes: not posted here init of all variables, don't be lazy try to learn a bit ;)