Messaging: Further code improvements

* Remove redundant casts
* getParcelable(ArrayList|Exra) without class argument is deprecated
* ViewPager.setOnPageChangeListener -> addOnPageChangeListener
* RecyclerView.setOnScrollListener -> addOnScrollListener
* Remove unused initializations
* Remove unused code

Change-Id: I21beb6c90c675a4f2cfd7e3d5ebbd18b745f5911

src/com/android/messaging/ui/attachmentchooser/AttachmentChooserFragment.java

@@ -63,7 +63,7 @@ public class AttachmentChooserFragment extends Fragment implements DraftMessageD
     public View onCreateView(final LayoutInflater inflater, final ViewGroup container,
             final Bundle savedInstanceState) {
         final View view = inflater.inflate(R.layout.attachment_chooser_fragment, container, false);
-        mAttachmentGridView = (AttachmentGridView) view.findViewById(R.id.grid);
+        mAttachmentGridView = view.findViewById(R.id.grid);
         mAdapter = new AttachmentGridAdapter(getActivity());
         mAttachmentGridView.setAdapter(mAdapter);
         mAttachmentGridView.setHost(this);

src/com/android/messaging/ui/attachmentchooser/AttachmentGridItemView.java

@@ -52,8 +52,8 @@ public class AttachmentGridItemView extends FrameLayout {
     @Override
     protected void onFinishInflate() {
         super.onFinishInflate();
-        mAttachmentViewContainer = (FrameLayout) findViewById(R.id.attachment_container);
-        mCheckBox = (CheckBox) findViewById(R.id.checkbox);
+        mAttachmentViewContainer = findViewById(R.id.attachment_container);
+        mCheckBox = findViewById(R.id.checkbox);
         mCheckBox.setOnClickListener(v -> mHostInterface.onItemCheckedChanged(
                 AttachmentGridItemView.this, mAttachmentData));
         setOnClickListener(v -> mHostInterface.onItemClicked(AttachmentGridItemView.this,

src/com/android/messaging/ui/attachmentchooser/AttachmentGridView.java

@@ -142,8 +142,8 @@ public class AttachmentGridView extends GridView implements
             final int partCount = in.readInt();
             unselectedParts = new MessagePartData[partCount];
             for (int i = 0; i < partCount; i++) {
-                unselectedParts[i] = ((MessagePartData) in.readParcelable(
-                        MessagePartData.class.getClassLoader()));
+                unselectedParts[i] = in.readParcelable(MessagePartData.class.getClassLoader(),
+                        MessagePartData.class);
             }
         }