仿页面首页缓存fragment，避免重复加载_framelayout 缓存 fragment-优快云博客

本文介绍了一种在Android应用中高效切换Fragment的方法，通过判断Fragment是否已加载来避免重复请求，同时提供了在切换时刷新数据的解决方案。利用getChildFragmentManager()和FragmentTransaction，实现了Fragment的显示与隐藏，而无需重新加载。

1、需求：点击下面的导航栏加载对应的fragment，其他的不加载，导航栏切换，如果fragment加载出来就不重新请求

直接调用replaceFragment方法：

public void replaceFragment(int pos) {
    Fragment tabFragment = getFragment(pos);
    FragmentManager fragmentManager = getChildFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    if (fragmentManager.getFragments() != null
            && fragmentManager.getFragments().contains(tabFragment)) {
        for (Fragment fragment : fragmentHashMap.values()) {
            fragmentTransaction = fragment.equals(tabFragment) ? fragmentTransaction
                    .show(fragment) : fragmentTransaction.hide(fragment);
        }
        fragmentTransaction.commit();
    } else {
        if (fragmentManager.getFragments() != null) {
            for (Fragment fragment : fragmentManager.getFragments()) {
                if (!tabFragment.equals(fragment)) {
                    fragmentTransaction.hide(fragment);
                }
            }
        }
        fragmentTransaction.add(R.id.fl_container, tabFragment)
                .show(tabFragment).commit();
    }
}

public Fragment getFragment(int pos) {
    Fragment fragment = fragmentHashMap.get(pos);
    if (fragment == null) {
        switch (pos) {
            case 0:
                fragment = InnerSkinFragment.getInstance(detectionId);
                break;
            case 1:
                fragment = InnerMBFragment.getInstance("美白",detectionId);
                break;
            case 2:
                fragment = InnerMBFragment.getInstance("减龄",detectionId);
                break;
        }
        fragmentHashMap.put(pos, fragment);
    }
    return fragment;
}

2、如果需要切换的时候刷新数据，可以调用fragment的onHiddenChange()方法.