片段交易未将我的片段识别为片段

Question

So i'm implementing a FragmentActivity and am trying to add a fragment, however I'm running into multiple problems. I've done this before, and am actually using the same code as the last project (where it worked), but for some reason it's not working here. Here's my code:

package silversphere.eyeon;

import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.widget.LinearLayout;

public class AlarmsActivity extends FragmentActivity {



    @Override
    public void onCreate(Bundle savedInstanceState)
    {
         super.onCreate(savedInstanceState);

         LinearLayout layout = new LinearLayout(this);
         layout.setId(40000);

         FragmentManager man = getFragmentManager();
         FragmentTransaction trans = man.beginTransaction();

         Alarm_Landing_Page_Fragment frag = new Alarm_Landing_Page_Fragment();

         trans.add(40000, frag);

    }

}

I'm getting an error on the layout.setId() call and also the trans.add(). The layout.setId() is saying "expected resource of type id" and the transaction is saying "cannot resolve method add(int, silversphere.eyeon.alarm_landing_page_fragment)", which to me suggests that for some reason it's not recognizing the Alarm_LandingPage_Fragment as a fragment, but it definitely should be. Here's the declaration for Alarm_Landing_Page_Fragment:

public class Alarm_Landing_Page_Fragment extends Fragment {

Any suggestions are appreciated!

Answer 1

You are mixing Fragment related classes from the support library with the ones shipped with SDK. Use either only support library classes or only SDK's built-in classes when working with Fragments (I mean only classes related to Fragment s).

If your class Alarm_Landing_Page_Fragment extends Fragment from the support library then change:

import android.app.FragmentManager;
import android.app.FragmentTransaction;

// ...

FragmentManager man = getFragmentManager();

to:

import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;

// ...

FragmentManager man = getSupportFragmentManager();

Otherwise, do not extend FragmentActivity and use only Fragment related classes from SDK.

Edit:

See also this answer: Error inflating class fragment (As ListFragment)

Answer 2

The problem is related to the setId . You have to create an <id> resource:

/res/values/ids.xml

<resources>
    <item type="id" name="myId" />
</resources>

An then, on your file:

LinearLayout layout = new LinearLayout(this);
layout.setId(R.id.myId);

...

trans.add(R.id.myId, frag);