Question

我正在使用ViewPager来允许用户在其视图之间滑动。有没有办法如何强制这个ViewPager重新加载/重新实例化它们的视图，以防它们不再有效或需要刷新？我尝试在其适配器上调用notifyDataSetChanged()，但这不会再次调用instantiateItem()方法。

修改

这是从ViewPager及其适配器定义扩展的类。 Bellow是我想要强制刷新项目时调用的refresh()方法。

public class DayFlipper extends ViewPager {

public class FlipperAdapter extends PagerAdapter {

    @Override
    public int getCount() {
        return DayFlipper.DAY_HISTORY;
    }

    @Override
    public void startUpdate(View container) {
    }

    @Override
    public Object instantiateItem(View container, int position) {
        Log.d(TAG, "instantiateItem(): " + position);

        Date d = DateHelper.getBot();
        for (int i = 0; i < position; i++) {
            d = DateHelper.getTomorrow(d);
        }

        d = DateHelper.normalize(d);

        CubbiesView cv = new CubbiesView(mContext);
        cv.setLifeDate(d);
        ((ViewPager) container).addView(cv, 0);
        // add map
        cv.setCubbieMap(mMap);
        cv.initEntries(d);
        return cv;
    }

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

    @Override
    public void finishUpdate(View container) {

    }

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

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void restoreState(Parcelable state, ClassLoader loader) {

    }

}

    ...

    public void refresh() {
    getAdapter().notifyDataSetChanged();
}
}

Answer 1

有同样的问题。对我而言，它致电

viewPage.setAdapter( adapter );

再次导致再次重新实现页面。

Answer 2

我找到了解决方案。这只是我的问题的解决方法，但目前是唯一的解决方案。

ViewPager PagerAdapter not updating the View

public int getItemPosition(Object object) {
   return POSITION_NONE;
}

有谁知道这是不是一个错误？

Answer 3

public class DayFlipper extends ViewPager {

private Flipperadapter adapter;
public class FlipperAdapter extends PagerAdapter {

    @Override
    public int getCount() {
        return DayFlipper.DAY_HISTORY;
    }

    @Override
    public void startUpdate(View container) {
    }

    @Override
    public Object instantiateItem(View container, int position) {
        Log.d(TAG, "instantiateItem(): " + position);

        Date d = DateHelper.getBot();
        for (int i = 0; i < position; i++) {
            d = DateHelper.getTomorrow(d);
        }

        d = DateHelper.normalize(d);

        CubbiesView cv = new CubbiesView(mContext);
        cv.setLifeDate(d);
        ((ViewPager) container).addView(cv, 0);
        // add map
        cv.setCubbieMap(mMap);
        cv.initEntries(d);
adpter = FlipperAdapter.this;
        return cv;
    }

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

    @Override
    public void finishUpdate(View container) {

    }

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

    @Override
    public Parcelable saveState() {
        return null;
    }

    @Override
    public void restoreState(Parcelable state, ClassLoader loader) {

    }

}

    ...

    public void refresh() {
    adapter().notifyDataSetChanged();
}
}

试试这个。

如何强制ViewPager重新实例化其项目

修改

3 个答案: