CODEWITHSUNDEEP
javaandroidandroid-fragmentsnavigation-drawer
Kim
Kim

Reputation: 160

Switching fragments in navigation drawer

I want to be able to use a navigation drawer and change between different fragments depending on selection in the navigation.

I'm using Android Studio and basically what I've done is this:

Then I change some code in the method onNavigationDrawerItemSelected. 

@Override  
public void onNavigationDrawerItemSelected(int position) {  
    // update the main content by replacing fragments  
    FragmentManager fragmentManager = getSupportFragmentManager();  
    Fragment fragment = new BlankFragment();  
    fragmentManager.beginTransaction()  
            .replace(R.id.container, fragment)  
            .commit();  
}

My program crashes and gives me lots of errors that I don't understand. What am I doing wrong?

4168-4168/com.dev.kim.mytestapplication E/AndroidRuntime﹕ FATAL
EXCEPTION: main
    Process: com.dev.kim.mytestapplication, PID: 4168
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dev.kim.mytestapplication/com.dev.kim.mytestapplication.MainActivity}:
java.lang.ClassCastException:
com.dev.kim.mytestapplication.MainActivity@e71881c must implement
OnFragmentInteractionListener
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.ClassCastException: com.dev.kim.mytestapplication.MainActivity@e71881c must implement
OnFragmentInteractionListener
            at com.dev.kim.mytestapplication.BlankFragment.onAttach(BlankFragment.java:83)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
            at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
            at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1220)
            at android.app.Activity.performStart(Activity.java:5949)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

Upvotes: 1

Views: 717

Answers (1)

James Black
James Black

Reputation: 41858

When you created the Fragment with the wizard you left checked a box to create a listener.

So you get this error:

must implement
OnFragmentInteractionListener

If you don't want to use the listener then in 'onAttach' you can remove this block of code:

try {
    mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
    throw new ClassCastException(activity.toString()
            + " must implement OnFragmentInteractionListener");
}

Or in your activity you can implement the listener.

Upvotes: 2

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