Question

My android app isn’t starting for some reason. it’s a really basic app. When I run it, it just says that it has to close and I press force close.

import com.actionbarsherlock.app.ActionBar.Tab;
import com.actionbarsherlock.app.ActionBar.TabListener;
import com.actionbarsherlock.app.*;
import com.actionbarsherlock.app.SherlockActivity;
import com.actionbarsherlock.app.ActionBar;
import com.actionbarsherlock.app.SherlockFragmentActivity;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.util.Log;


public class MainActivity extends SherlockFragmentActivity implements TabListener{

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        Tab tabRed = actionBar.newTab();
        tabRed.setText("Red Side");
      //  tabRed.setTabListener(new TabListener<TabFragment>(this, "tab1", TabFragment.class));
        Tab tabBlue = actionBar.newTab();
        tabBlue.setText("Blue Side");
       // tabBlue.setTabListener(new TabListener<TabFragment>(this, tabBlue, TabFragment.class));

        actionBar.addTab(tabRed);
        actionBar.addTab(tabBlue);


    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        Log.d("Main Activity", "tab " + String.valueOf(tab.getPosition()) + " clicked");

    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        Log.d("Main Activity", "tab " + String.valueOf(tab.getPosition())+ " un-clicked");

    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        Log.d("Main Activity", "tab " + String.valueOf(tab.getPosition()) + " re-clicked");


    }



}

This is my activity_main.xml, which just has text in it. Do I have to set up the action bar in the xml as well?

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >



     <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="@string/hello_world" />

</RelativeLayout>

The logcat

12-22 00:19:37.846: E/AndroidRuntime(1833): FATAL EXCEPTION: main
12-22 00:19:37.846: E/AndroidRuntime(1833): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.say.upscorer/org.say.upscorer.MainActivity}: java.lang.IllegalStateException: Action Bar Tab must have a Callback
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.os.Looper.loop(Looper.java:123)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.ActivityThread.main(ActivityThread.java:4627)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at java.lang.reflect.Method.invokeNative(Native Method)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at java.lang.reflect.Method.invoke(Method.java:521)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at dalvik.system.NativeStart.main(Native Method)
12-22 00:19:37.846: E/AndroidRuntime(1833): Caused by: java.lang.IllegalStateException: Action Bar Tab must have a Callback
12-22 00:19:37.846: E/AndroidRuntime(1833):     at com.actionbarsherlock.internal.app.ActionBarImpl.configureTab(ActionBarImpl.java:424)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at com.actionbarsherlock.internal.app.ActionBarImpl.addTab(ActionBarImpl.java:450)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at com.actionbarsherlock.internal.app.ActionBarImpl.addTab(ActionBarImpl.java:438)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at org.say.upscorer.MainActivity.onCreate(MainActivity.java:33)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-22 00:19:37.846: E/AndroidRuntime(1833):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
12-22 00:19:37.846: E/AndroidRuntime(1833):     ... 11 more

Answer 1

Each of your Tabs must have a TabListener, for instance:

Tab tabRed = actionBar.newTab();
tabRed.setText("Red Side");
tabRed.setTabListener(this);
actionBar.addTab(tabRed);

// The same is true for tabBlue