无法解析符号“ content_frame”

Question

I seem to have a rather persistent error with my android studio. In each project I get the error cannot resolve symbol "content_frame" in lines like

fragmentManager.beginTransaction().replace(R.id.content_frame, new Setting_new()).commit();

I already did a "invalidate cache and restart", followed by a clean project and a rebuild project. While doing the rebuilding it gave the error

Compilation failed; see the compiler error output for details.

And on the right it said error: cannot find symbol variable content_frame I don't know if it is the error output the other message was mentioning.

Like I mentioned it is in each project, I made a new project with a menu drawer and just added this to the drawer and it gave an error. I've also downloaded a new installer and reinstalled android studio with it but it made no difference.

Answer 1

You are trying to add fragment using

fragmentManager.beginTransaction().replace(R.id.content_frame, new Setting_new()).commit();

where container R.id.content_frame is the id of the View where your Setting_new will be displayed(added).

Add Container View in your Activity's xml file, something like...

<FrameLayout
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Answer 2

The issue is here: fragmentManager.beginTransaction().replace(R.id.content_frame, new Setting_new()).commit();

Make sure that your FrameLayout, in which to add the Fragment exists in your .xml file:

 <!-- Frame Layout for Fragments -->
<FrameLayout
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginTop="?android:actionBarSize"/>

Answer 3

It is trying to look for the id content_frame where your fragment would be loaded.

You can use something like below in your Activity's xml file:-

<FrameLayout
    android:id="@+id/content_frame" // ----------> id where fragment would be loaded.
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>