在片段中处理onBackPressed在Android中

Question

我要处理片段

中的onBackPressed

我在活动中使用以下代码，但返回0

@Override
    public void onBackPressed() {

    int count = getFragmentManager().getBackStackEntryCount();

    Toast.makeText(getBaseContext(), ""+count, Toast.LENGTH_SHORT).show();
    if (count == 1) {
        super.onBackPressed();
        //additional code
    } else {
        getFragmentManager().popBackStack();
    }

}

Answer 1

只需在您的.addToBackStack(null)或Activity中添加Fragment即可。添加或替换fragment时。像下面一样

 getSupportFragmentManager().beginTransaction().replace(R.id.parent_layout, new MyFragment()).addToBackStack(null).commit();

注意：-您无需在onBackPressed()方法中做任何事情。

Answer 2

Just app this line when you want to replace any fragment and manage backsack on Fragment.

ClientHome per = new ClientHome();
                Bundle bundle = new Bundle();
                bundle.putString("usertype", "client");
                per.setArguments(bundle);
                FragmentManager fragmentManager = getFragmentManager();
                FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
                fragmentTransaction.setCustomAnimations(R.anim.slide_from_left, R.anim.slide_to_right);
                fragmentTransaction.replace(R.id.content_frame, per, "tag");
                fragmentTransaction.addToBackStack("tag");
                fragmentTransaction.commit();