Disable tab switching in media overview during multiselect.

Multiselect only applies to items in the "media" tab, so people
shouldn't be able to switch tabs during multiselect.

res/layout/media_overview_activity.xml

@@ -18,7 +18,7 @@
                 android:titleTextColor="?attr/media_overview_toolbar_foreground"
                 app:layout_scrollFlags="scroll|enterAlways"/>
 
-        <android.support.design.widget.TabLayout
+        <org.thoughtcrime.securesms.components.ControllableTabLayout
                 android:id="@+id/tab_layout"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
@@ -30,7 +30,7 @@
 
     </android.support.design.widget.AppBarLayout>
 
-    <android.support.v4.view.ViewPager
+    <org.thoughtcrime.securesms.components.ControllableViewPager
             android:id="@+id/pager"
             android:layout_width="match_parent"
             android:layout_height="match_parent"

src/org/thoughtcrime/securesms/MediaOverviewActivity.java

@@ -71,7 +71,7 @@ import java.util.Locale;
 /**
  * Activity for displaying media attachments in-app
  */
-public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity  {
+public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity {
 
   @SuppressWarnings("unused")
   private final static String TAG = MediaOverviewActivity.class.getSimpleName();
@@ -137,6 +137,16 @@ public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity
     this.recipient.addListener(recipient -> getSupportActionBar().setTitle(recipient.toShortString()));
   }
 
+  public void onEnterMultiSelect() {
+    tabLayout.setEnabled(false);
+    viewPager.setEnabled(false);
+  }
+
+  public void onExitMultiSelect() {
+    tabLayout.setEnabled(true);
+    viewPager.setEnabled(true);
+  }
+
   private class MediaOverviewPagerAdapter extends FragmentStatePagerAdapter {
 
     MediaOverviewPagerAdapter(FragmentManager fragmentManager) {
@@ -270,8 +280,7 @@ public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity
 
       adapter.toggleSelection(mediaRecord);
       if (adapter.getSelectedMediaCount() == 0) {
-        actionMode.finish();
+        exitMultiSelect();
-        actionMode = null;
       } else {
         actionMode.setTitle(String.valueOf(adapter.getSelectedMediaCount()));
       }
@@ -304,7 +313,7 @@ public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity
         ((MediaGalleryAdapter) recyclerView.getAdapter()).toggleSelection(mediaRecord);
         recyclerView.getAdapter().notifyDataSetChanged();
 
-        actionMode = ((AppCompatActivity) getActivity()).startSupportActionMode(actionModeCallback);
+        enterMultiSelect();
       }
     }
 
@@ -352,6 +361,17 @@ public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity
       return (MediaGalleryAdapter) recyclerView.getAdapter();
     }
 
+    private void enterMultiSelect() {
+      actionMode = ((AppCompatActivity) getActivity()).startSupportActionMode(actionModeCallback);
+      ((MediaOverviewActivity) getActivity()).onEnterMultiSelect();
+    }
+
+    private void exitMultiSelect() {
+      actionMode.finish();
+      actionMode = null;
+      ((MediaOverviewActivity) getActivity()).onExitMultiSelect();
+    }
+
     private class ActionModeCallback implements ActionMode.Callback {
 
       private int originalStatusBarColor;
@@ -379,7 +399,7 @@ public class MediaOverviewActivity extends PassphraseRequiredActionBarActivity
         switch (menuItem.getItemId()) {
           case R.id.delete:
             handleDeleteMedia(getListAdapter().getSelectedMedia());
-            mode.finish();
+            exitMultiSelect();
             return true;
         }
         return false;

src/org/thoughtcrime/securesms/components/ControllableTabLayout.java

@@ -0,0 +1,41 @@
+package org.thoughtcrime.securesms.components;
+
+import android.content.Context;
+import android.support.design.widget.TabLayout;
+import android.util.AttributeSet;
+import android.view.View;
+
+import java.util.List;
+
+/**
+ * An implementation of {@link TabLayout} that disables taps when the view is disabled.
+ */
+public class ControllableTabLayout extends TabLayout {
+
+  private List<View> touchables;
+
+  public ControllableTabLayout(Context context) {
+    super(context);
+  }
+
+  public ControllableTabLayout(Context context, AttributeSet attrs) {
+    super(context, attrs);
+  }
+
+  public ControllableTabLayout(Context context, AttributeSet attrs, int defStyleAttr) {
+    super(context, attrs, defStyleAttr);
+  }
+
+  @Override
+  public void setEnabled(boolean enabled) {
+    if (isEnabled() && !enabled) {
+      touchables = getTouchables();
+    }
+
+    for (View touchable : touchables) {
+      touchable.setClickable(enabled);
+    }
+
+    super.setEnabled(enabled);
+  }
+}

src/org/thoughtcrime/securesms/components/ControllableViewPager.java

@@ -0,0 +1,32 @@
+package org.thoughtcrime.securesms.components;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+
+/**
+ * An implementation of {@link ViewPager} that disables swiping when the view is disabled.
+ */
+public class ControllableViewPager extends ViewPager {
+
+  public ControllableViewPager(@NonNull Context context) {
+    super(context);
+  }
+
+  public ControllableViewPager(@NonNull Context context, @Nullable AttributeSet attrs) {
+    super(context, attrs);
+  }
+
+  @Override
+  public boolean onTouchEvent(MotionEvent ev) {
+    return isEnabled() && super.onTouchEvent(ev);
+  }
+
+  @Override
+  public boolean onInterceptTouchEvent(MotionEvent ev) {
+    return isEnabled() && super.onInterceptTouchEvent(ev);
+  }
+}