Android比较两个片段

Question

当我更改片段时,我想将新片段与当前片段进行比较.如果它们相同,则无需更换它们.

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,即使新的片段是相同的,片段也会改变

一个办法 ？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

识别片段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,使用类名作为标记:

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(); 
    }
}