Activity更新Fragment_activity 更新 frahmenui-优快云博客

本文链接：https://blog.youkuaiyun.com/ChengTaoYan/article/details/52410847

本文介绍了在Android中如何在Activity中更新Fragment，包括使用TabLayout+ViewPager的方式，以及两种不同的适配器实现方法：FragmentStatePagerAdapter和清除缓存的Fragment添加方式。

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Activity更新Fragment

(TabLayout ViewPager Fragment)

在activity里调用

adapter.notifyDataSetChanged();

适配器的写法：

方法1：（适配器继承FragmentStatePagerAdapter）

public class CoursePagerAdapter extends FragmentStatePagerAdapter {
    private final List<Fragment> mFragments = new ArrayList<>();
    private final List<String> mFragmentTitles = new ArrayList<>();
    FragmentManager fm;

    public CoursePagerAdapter(FragmentManager fm) {
        super(fm);
        this.fm = fm;
    }


    public void addFragment(Fragment fragment, String title) {
        mFragments.add(fragment);
        mFragmentTitles.add(title);
    }

    public void clearFragment() {
        mFragments.clear();
    }

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

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

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

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

}

方法2：(添加清除缓存的Fragment)

public class CoursePagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragments = new ArrayList<>();
    private final List<String> mFragmentTitles = new ArrayList<>();
    FragmentManager fm;

    public CoursePagerAdapter(FragmentManager fm) {
        super(fm);
        this.fm = fm;
    }


    public void addFragment(Fragment fragment, String title) {
        mFragments.add(fragment);
        mFragmentTitles.add(title);
    }

    public void clearFragment() {
        removeALlFragments();
        mFragments.clear();
    }

    private void removeALlFragments(){
        FragmentTransaction transaction = fm.beginTransaction();
        for (int i=0; i<mFragments.size(); i++){
            Fragment fg = mFragments.get(i);
            transaction.remove(fg);
        }
        transaction.commit();
        mFragments.clear();
    }
     @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        super.destroyItem(container, position, object);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

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

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

}