android Fragment的坑

1、FragmentTransaction

FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();

fragmentTransaction在commit的之后不能复用，必须重新

fragmentTransaction = getSupportFragmentManager().beginTransaction();

不然会报错：

java.lang.IllegalStateException: commit already called

2、多个fragment需要新建和替换

FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();if (fragment == null) {    fragment = new Fragment();    fragmentTransaction.add(R.id.content, fragment).commit();    if (currentFragment != null) {        // 1        fragmentManager.beginTransaction().hide(currentFragment).commit();    }} else {    fragmentTransaction.show(fragment).hide(currentFragment).commit();}currentFragment = fragment;

在1的地方，当currentFragment不为空时，需要隐藏掉，不然新的fragment会覆盖在currentFragment之上，在fragment的空白区域点击，会触发currentFragment在该区域的点击事件。