android - 选择选项卡时如何重新加载 fragment ？

Question

我创建了一个简单的应用程序，其中包含 3 个选项卡 TAB1、TAB2、TAB3当我选择相邻的 TAB1 时，TAB2 被加载到内存中，然后当我按下 TAB2 或 TAB3 时，我在 TAB2 上的内容将不会刷新。

如果我按 TAB1->TAB2->TAB1->TAB2 顺序单击选项卡，我的 fragment 将不会刷新

我想在每次选择标签时加载所选标签。

我正在使用以下代码在所选选项卡上加载 fragment

public class SampleFragmentPageAdapter extends FragmentStatePagerAdapter {

final int PAGE_COUNT = 3;
private String tabTitles[] = new String[]{"HOME", "BEACON", "NEARBY"};
private int[] imageResId = {
        R.drawable.home,
        R.drawable.beacon,
        R.drawable.nearby
};
private Context context;

public SampleFragmentPageAdapter(FragmentManager fm, Context context) {
    super(fm);
    this.context = context;
}

@Override
public Fragment getItem(int position) {
    Fragment fragment = null;
    if (position == 0)
        fragment = new FragmentTab1();
    if (position == 1)
        fragment = new FragmentTab2();
    if (position == 2)
        fragment = new FragmentTab3();
    return fragment;
}

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

@Override
public CharSequence getPageTitle(int position) {
    // Generate title based on item position
    Drawable image = context.getResources().getDrawable(imageResId[position]);
    image.setBounds(0, 0, 32, 32);
    // Replace blank spaces with image icon
    SpannableString sb = new SpannableString("   " + tabTitles[position]);
    ImageSpan imageSpan = new ImageSpan(image, ImageSpan.ALIGN_BOTTOM);
    sb.setSpan(imageSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    return sb;
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
    return super.instantiateItem(container, position);
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
    super.destroyItem(container, position, object);
}
}

Answer 1

Your_Pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            if (position == WHATEVER) {
                //do your Staff

            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });

您可以访问这里了解更多信息

http://developer.android.com/reference/android/support/v4/view/ViewPager.OnPageChangeListener.html