Fixed issue 472, NPE on android 3.1 (and 3.0).

The Activity.getActionBar() method can only be called after
setContentView() has been invoked, as described here:

  http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html

I couldn't think of any way to enforce this safely
(i.e. make the compiler kick up a stink if we didn't do it). As such,
I just put a comment above each usage of the ActionBarCompat class.

Another outstanding issue is a duplicate of 474, where it crashes when you
press the "Up" button from ManageRepos, but I'll create a different issue
for that.

src/org/fdroid/fdroid/AppDetails.java

@@ -261,11 +261,13 @@ public class AppDetails extends ListActivity {
             .bitmapConfig(Bitmap.Config.RGB_565)
             .build();
 
-        ActionBarCompat abCompat = ActionBarCompat.create(this);
-        abCompat.setDisplayHomeAsUpEnabled(true);
-
         setContentView(R.layout.appdetails);
 
+        // Actionbar cannot be accessed until after setContentView (on 3.0 and 3.1 devices)
+        // see: http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
+        // for reason why.
+        ActionBarCompat.create(this).setDisplayHomeAsUpEnabled(true);
+
         Intent i = getIntent();
         Uri data = i.getData();
         if (data != null) {

src/org/fdroid/fdroid/ManageRepo.java

@@ -27,6 +27,7 @@ import android.support.v4.app.NavUtils;
 import android.util.Log;
 import android.view.MenuItem;
 
+import android.widget.LinearLayout;
 import org.fdroid.fdroid.compat.ActionBarCompat;
 import org.fdroid.fdroid.views.fragments.RepoListFragment;
 
@@ -49,6 +50,14 @@ public class ManageRepo extends FragmentActivity {
         ((FDroidApp) getApplication()).applyTheme(this);
 
         if (savedInstanceState == null) {
+
+            // Need to set a dummy view (which will get overridden by the fragment manager
+            // below) so that we can call setContentView(). This is a work around for
+            // a (bug?) thing in 3.0, 3.1 which requires setContentView to be invoked before
+            // the actionbar is played with:
+            // http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
+            setContentView( new LinearLayout(this) );
+
             listFragment = new RepoListFragment();
             getSupportFragmentManager()
                 .beginTransaction()

src/org/fdroid/fdroid/PreferencesActivity.java

@@ -59,7 +59,12 @@ public class PreferencesActivity extends PreferenceActivity implements
     protected void onCreate(Bundle savedInstanceState) {
         ((FDroidApp) getApplication()).applyTheme(this);
         super.onCreate(savedInstanceState);
+
+        // Actionbar cannot be accessed until after setContentView (on 3.0 and 3.1 devices)
+        // see: http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
+        // for reason why.
         ActionBarCompat.create(this).setDisplayHomeAsUpEnabled(true);
+
         addPreferencesFromResource(R.xml.preferences);
     }
 

src/org/fdroid/fdroid/SearchResults.java

@@ -73,9 +73,14 @@ public class SearchResults extends ListActivity {
         ((FDroidApp) getApplication()).applyTheme(this);
 
         super.onCreate(savedInstanceState);
-        ActionBarCompat.create(this).setDisplayHomeAsUpEnabled(true);
+
         setContentView(R.layout.searchresults);
 
+        // Actionbar cannot be accessed until after setContentView (on 3.0 and 3.1 devices)
+        // see: http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
+        // for reason why.
+        ActionBarCompat.create(this).setDisplayHomeAsUpEnabled(true);
+
         // Start a search by just typing
         setDefaultKeyMode(DEFAULT_KEYS_SEARCH_LOCAL);
     }

src/org/fdroid/fdroid/compat/ActionBarCompat.java

@@ -20,6 +20,15 @@ public abstract class ActionBarCompat extends Compatibility {
         this.activity = activity;
     }
 
+    /**
+     * Cannot be accessed until after setContentView (on 3.0 and 3.1 devices) has
+     * been called on the relevant activity. If you don't have a content view
+     * (e.g. when using fragment manager to add fragments to the activity) then you
+     * will still need to call setContentView(), with a "new LinearLayout()" or something
+     * useless like that.
+     * See: http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
+     * for details.
+     */
     public abstract void setDisplayHomeAsUpEnabled(boolean value);
 
 }

src/org/fdroid/fdroid/views/RepoDetailsActivity.java

@@ -15,6 +15,7 @@ import android.os.Parcelable;
 import android.support.v4.app.FragmentActivity;
 import android.text.TextUtils;
 import android.util.Log;
+import android.widget.LinearLayout;
 import android.widget.Toast;
 
 import org.fdroid.fdroid.FDroidApp;
@@ -41,6 +42,14 @@ public class RepoDetailsActivity extends FragmentActivity {
         long repoId = getIntent().getLongExtra(RepoDetailsFragment.ARG_REPO_ID, 0);
 
         if (savedInstanceState == null) {
+
+            // Need to set a dummy view (which will get overridden by the fragment manager
+            // below) so that we can call setContentView(). This is a work around for
+            // a (bug?) thing in 3.0, 3.1 which requires setContentView to be invoked before
+            // the actionbar is played with:
+            // http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
+            setContentView( new LinearLayout(this) );
+
             RepoDetailsFragment fragment = new RepoDetailsFragment();
             fragment.setArguments(getIntent().getExtras());
             getSupportFragmentManager()