android.support.v4.view.ViewPager#getTag ( )源码实例Demo

/**
 * (伪)双向 databinding: 同 {@link RecyclerViewAdapter#setDataTwoWay(RecyclerView, ListVM, List)}
 *
 * @param container
 * @param vm
 * @param datas
 * @param <T>
 */
@BindingAdapter({"vm", "data"})
public static <T> void setDataTwoWay(final ViewPager container, final ListVM<T> vm, List<T> datas){
    if(vm == null){
        return ;
    }
    bind(container, vm, datas);

    if(vm instanceof TwoWayListVM) {
        boolean isInited = container.getTag(R.id.db_inited) != null;
        if (!isInited) {
            container.setTag(R.id.db_inited, true);
            loadData(container, (TwoWayListVM<T>) vm, null, null);
        }
    }
}
 

@BindingAdapter("adapter")
public static void bindAdapter(@NonNull ViewPager viewPager, @Nullable PagerAdapter adapter) {
    PagerAdapter oldAdapter = viewPager.getAdapter();

    // Disconnect previous adapter if its Connectable
    if (oldAdapter != null && oldAdapter instanceof Connectable) {
        Disposable subscription = (Disposable) viewPager.getTag(R.integer.tag_subscription);
        if (subscription != null && !subscription.isDisposed()) {
            subscription.dispose();
        }
        viewPager.setTag(R.integer.tag_subscription, null);
    }

    // Store connection (Subscription) if new adapter is Connectable
    if (adapter != null && adapter instanceof Connectable) {
        viewPager.setTag(R.integer.tag_subscription, ((Connectable) adapter).connect());
    }
    viewPager.setAdapter(adapter);
}
 

/**
 * Sets a {@link android.support.v4.view.ViewPager.PageTransformer} to the given ViewPager.
 * Using this method to set PageTransformer is required for the ViewPagers that already have
 * {@link SparkleAnimationPresenter} installed.
 *
 * @param viewPager ViewPager instance.
 * @param reversDrawingOrder Whether the ViewPager should reverse it child Views' drawing
 * order.
 * @param transformer PageTransformer instance.
 * @see {@link ViewPager#setPageTransformer(boolean, ViewPager.PageTransformer)}
 * @see {@link android.support.v4.view.ViewPager.PageTransformer}
 */
public static void setPageTransformer(@NonNull ViewPager viewPager, boolean reversDrawingOrder,
        @Nullable final ViewPager.PageTransformer transformer) {
    Object tagObject = viewPager.getTag(R.id.presenter_id);
    if (tagObject == null || !(tagObject instanceof SparkleAnimationPresenter)) {
        viewPager.setPageTransformer(reversDrawingOrder, transformer);
        return;
    }

    final SparkleAnimationPresenter presenter = (SparkleAnimationPresenter) tagObject;
    ViewPager.PageTransformer transformerWrapper = new ViewPager.PageTransformer() {
        @Override
        public void transformPage(View page, float position) {
            int pageWidth = page.getWidth();
            float offset = pageWidth * -position;

            presenter.presentAnimations(page, position, offset);
            if (transformer != null) {
                transformer.transformPage(page, position);
            }
        }
    };

    viewPager.setPageTransformer(reversDrawingOrder, transformerWrapper);
}
 

@Override
public void hookView(View view) {
    ViewPager viewPager = (ViewPager) view;
    Object tag = viewPager.getTag(HOOK_VIEW_TAG);
    if (tag != null && !(tag instanceof Boolean)) {
        return;
    }
    Boolean added = (Boolean) tag;
    if (added != null && added) {
        return;
    }
    viewPager.addOnPageChangeListener(new ViewPagerOnPageChangeListener());
    viewPager.setTag(HOOK_VIEW_TAG, true);
    TrackerLog.d("ViewPager addOnPageChangeListener.");
}
 

/**
 * Gets the {@link SparkleAnimationPresenter} instance attached to the given ViewPager.
 *
 * @param viewPager ViewPager instance.
 * @return SparkleAnimationPresenter instance if set, or null.
 */
static SparkleAnimationPresenter getAnimationPresenter(ViewPager viewPager) {
    if (viewPager == null) {
        return null;
    }

    Object tagObject = viewPager.getTag(R.id.presenter_id);
    if (tagObject == null || !(tagObject instanceof SparkleAnimationPresenter)) {
        return null;
    }

    return (SparkleAnimationPresenter) tagObject;
}