Android fragment动态切换

全局变量

FragmentManager fragmentManager = getSupportFragmentManager();

activity中初始化

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        if (savedInstanceState != null) {
            Fragment oldfragment = fragmentManager.findFragmentByTag("tag");
            fragmentTransaction.add(R.id.fl_main, oldfragment, "tag");
        } else {
            changeFrgment(1);
            fragment_index = new IndexFragment();
            fragmentTransaction.add(R.id.fl_main, fragment_index, "tag");
        }
        fragmentTransaction.commit();

按钮切换fragment举例：

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        switch (view.getId()) {
            case R.id.ll_index_main:
                changeFrgment(1);
                fragment_index = new IndexFragment();
                fragmentTransaction.replace(R.id.fl_main, fragment_index, "tag");
                fragmentTransaction.commit();
                break;
}