Android比较两个 fragment

Question

当我更改 fragment 时，我想将新 fragment 与当前 fragment 进行比较。如果相同，则无需更换。

我试过了

 public void displayFragment(Fragment fragment){
    FragmentManager fm = getSupportFragmentManager();
    Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
    if(!currentFragment.equals(fragment))
        getSupportFragmentManager().beginTransaction().addToBackStack(null).replace(R.id.content_frame, fragment).commit();
}

但它不起作用，即使新 fragment 相同， fragment 也会更改

解决方案？ 谢谢

编辑

解决方案:

public void displayFragment(Fragment fragment){
    FragmentManager fm = getSupportFragmentManager();
    Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
    if(!fragment.getClass().toString().equals(currentFragment.getTag())){
        getSupportFragmentManager()
        .beginTransaction()
        .addToBackStack(null)
        .replace(R.id.content_frame, fragment, fragment.getClass().toString()) // add and tag the new fragment
        .commit();
    }
}

Answer 1

识别 fragment 的一种方法是给它们标签:

public void displayFragment(Fragment fragment, String tag){
    FragmentManager fm = getSupportFragmentManager();
    Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
    if(!tag.equals(currentFragment.getTag())
        getSupportFragmentManager()
        .beginTransaction()
        .addToBackStack(null)
        .replace(R.id.content_frame, fragment, tag) // add and tag the new fragment
        .commit();
}

编辑:psv 评论的替代版本，使用类名作为标签:

public void displayFragment(Fragment fragment){ 
    FragmentManager fm = getSupportFragmentManager();
    Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
    if(!fragment.getClass().toString().equals(currentFragment.getTag()))
    { 
        getSupportFragmentManager()
        .beginTransaction()
        .addToBackStack(null)
        .replace(R.id.content_frame, fragment, fragment.getClass().toString()) // add and tag the new fragment
        .commit(); 
    }
}