alexfu · June 21, 2024 19:11 · Jun 17, 2013 · Jun 17, 2013 · Jun 17, 2013 · Jun 17, 2013
diff --git a/MyActivity.java b/MyActivity.java
@@ -1,10 +1,15 @@
 public class MyActivity extends Activity {
-    private ViewPager mPager;
+    private MyAdapter mPagerAdapter;
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         setContentView(R.layout.my_activity);
-        mPager = (ViewPager) findViewById(R.id.pager);
-        mPager.setAdapter(new MyAdapter());
-    }    
+        ViewPager pager = (ViewPager) findViewById(R.id.pager);
+        mPagerAdapter = new MyAdapter();
+        pager.setAdapter(mPagerAdapter);
+    }
+
+    private void updateFragments() {
+        mPagerAdapter.updateFragments();
+    }
 }
diff --git a/MyAdapter.java b/MyAdapter.java
@@ -13,11 +13,9 @@ public Fragment getItem(int position) {
             mObservers.addObserver((Observer) fragment);
 
         return fragment;
-    }    
+    }
 
-    @Override
-    public void notifyDataSetChanged() {
+    public void updateFragments() {
         mObservers.notifyObservers();
-        super.notifyDataSetChanged();
     }
 }
diff --git a/MyAdapter.java b/MyAdapter.java
@@ -7,6 +7,7 @@ public MyAdapter(FragmentManager fm) {
 
     @Override
     public Fragment getItem(int position) {
+        mObservers.deleteObservers(); // Clear existing observers.
         Fragment fragment = new MyFragment();
         if(fragment instanceof Observer)
             mObservers.addObserver((Observer) fragment);

diff --git a/MyActivity.java b/MyActivity.java
@@ -0,0 +1,10 @@
+public class MyActivity extends Activity {
+    private ViewPager mPager;
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        setContentView(R.layout.my_activity);
+        mPager = (ViewPager) findViewById(R.id.pager);
+        mPager.setAdapter(new MyAdapter());
+    }    
+}
diff --git a/FragmentObserver.java b/FragmentObserver.java
@@ -0,0 +1,7 @@
+public class FragmentObserver extends Observable {
+    @Override
+    public void notifyObservers() {
+        setChanged(); // Set the changed flag to true, otherwise observers won't be notified.
+        super.notifyObservers();
+    }
+}
diff --git a/MyAdapter.java b/MyAdapter.java
@@ -0,0 +1,22 @@
+public class MyAdapter extends FragmentPagerAdapter {
+    private Observable mObservers = new FragmentObserver();
+
+    public MyAdapter(FragmentManager fm) {
+        super(fm);
+    }
+
+    @Override
+    public Fragment getItem(int position) {
+        Fragment fragment = new MyFragment();
+        if(fragment instanceof Observer)
+            mObservers.addObserver((Observer) fragment);
+
+        return fragment;
+    }    
+
+    @Override
+    public void notifyDataSetChanged() {
+        mObservers.notifyObservers();
+        super.notifyDataSetChanged();
+    }
+}
diff --git a/MyFragment.java b/MyFragment.java
@@ -0,0 +1,10 @@
+public class MyFragment extends Fragment implements Observer {
+
+    /* Fragment related stuff... */
+
+    @Override
+    public void update(Observable observable, Object data) {
+        View root = getView();
+        // Update your views here.
+    }
+}