Fragment的懒加载

private FragmentTransaction switchFragment(Fragment targetFragment) {


         FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
         if (!targetFragment.isAdded()) {
 //第一次使用switchFragment()时currentFragment为null，所以要判断一下
         if (currentFragment != null) {
               transaction.hide(currentFragment);
 }
        transaction.add(R.id.frame, targetFragment,targetFragment.getClass().getName());

 } else {
         transaction.hide(currentFragment).show(targetFragment);
 }
 currentFragment = targetFragment;
  return transaction;

 }

当点击下方按钮切换页面时调用此方法，传入要显示的fragment即可，记得最后commit下。