Question

OK, I must be overlooking something silly because I am unable to get my tabhost to display in my Activity class. I am getting the dreaded force close when I try to run the app. It will work if i extend TabActivity, but I can’t do that [see edit below] because once I move the code from my prototype project its going to be in a custom class that inherits from Activity.

Here is the XML layout:

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">    
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">        
        <TabWidget 
            android:id="@android:id/tabs"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" />            
        <FrameLayout 
            android:id="@android:id/tabcontent"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />
    </LinearLayout>
</TabHost>

And here is the class that is trying to create and display the TabHost:

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.widget.TabHost;

public class my_proto extends Activity
{   
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState)
   {
      Log.i(this.toString(), "OnCreate");

      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);

      Log.i(this.toString(), "get tab host");
      TabHost host = (TabHost)findViewById(R.id.tabhost); 
      host.setup();

      Log.i(this.toString(), "add tabs");
      host.addTab(host.newTabSpec("one")
                      .setIndicator("First Results")
                      .setContent(new Intent(this, FirstResultsListViewActivity.class)));

      host.addTab(host.newTabSpec("two")
                      .setIndicator("Second Results")
                      .setContent(new Intent(this, SecondResultsListViewActivity.class)));

      Log.i(this.toString(), "adjust tab size");
      host.getTabWidget().getChildAt(0).getLayoutParams().height = 35;
      host.getTabWidget().getChildAt(1).getLayoutParams().height = 35;

   }// end onCreate

}// end class my_proto

This is the error I get in the log.

11-17 16:49:51.271: INFO/com.my_proto.my_proto@43b80b50(1302): OnCreate
11-17 16:49:51.472: INFO/com.my_proto.my_proto@43b80b50(1302): get tab host
11-17 16:49:51.480: INFO/com.my_proto.my_proto@43b80b50(1302): add tabs
11-17 16:49:51.521: DEBUG/AndroidRuntime(1302): Shutting down VM
11-17 16:49:51.521: WARN/dalvikvm(1302): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
11-17 16:49:51.530: ERROR/AndroidRuntime(1302): Uncaught handler: thread main exiting due to uncaught exception
11-17 16:49:51.552: ERROR/AndroidRuntime(1302): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.my_proto/com.my_proto.my_proto}: java.lang.IllegalStateException: Did you forget to call 'public void setup(LocalActivityManager activityGroup)'?
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.os.Looper.loop(Looper.java:123)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.ActivityThread.main(ActivityThread.java:4363)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at java.lang.reflect.Method.invokeNative(Native Method)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at java.lang.reflect.Method.invoke(Method.java:521)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at dalvik.system.NativeStart.main(Native Method)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302): Caused by: java.lang.IllegalStateException: Did you forget to call 'public void setup(LocalActivityManager activityGroup)'?
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:646)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.widget.TabHost.setCurrentTab(TabHost.java:320)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.widget.TabHost.addTab(TabHost.java:213)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at com.mc_proto.mc_proto.onCreate(my_proto.java:29)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
11-17 16:49:51.552: ERROR/AndroidRuntime(1302):     ... 11 more

Its complaining about not calling setup, but I am calling it. There is another version of setup that needs some kind of LocalActivityMananger. I have tried replacing the call to setup the call below but no luck.

LocalActivityManager mLocalActivityManager = new LocalActivityManager(this, false);
host.setup(mLocalActivityManager);

[edit] The call above didn’t work so I took it back out. Although I was getting a new error logged.

11-17 20:24:58.382: ERROR/AndroidRuntime(1432): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.my_proto/com.my_proto.my_proto}: java.lang.IllegalStateException: Activities can't be added until the containing group has been created.

[edit] Based on some of the comments below I realized I need to be clearer about why I can’t inherit from TabActivity. Once I have the prototype working I need to port this into an existing app’s screen that inherits from Activity. I will need to load the TabHost into a Layout within that Activity. It will basically be a LinearLayout with a row of status icons, followed my a LinearLayout with the Tabhost in it. I know that if I can get this working I can move onto the next phase. Thanks!

---------------------------
|      status icons       |
---------------------------
|    Tab, Tab, Tab        |
|                         |
|                         |
|                         | 
---------------------------
|      status icons       |
---------------------------

Answer 1

Ok I figured it out. Apparently, TabActivity extends ActivityGroup, which extends Activity. But in your code your class extends Activity which is not an activity group.

So there are two options:

1) If you want the tab content to be activities, have your class extend ActivityGroup (instead of Activity). Then your call to setup should be host.setup(getLocalActivityManager());

This way you are emulating the TabActivity source code.

2) If you can have your tab content be views (vs activities), keep your class as extending from Activity, and keep your call to setup(). But for the setContent part do something like this:

host.addTab(host.newTabSpec("two")
                .setIndicator("Second Results")
                .setContent(new TabContentFactory() {

                    public View createTabContent(String tag) {
                        return new TextView(TestActivity.this);
                    }
                }));

And then define your list view inside createTabContent (that’s usually what I do – I prefer using views instead of activities as the contents of the tabs).