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/mmslib/pdu/PduComposer.java

@@ -96,22 +96,22 @@ public class PduComposer {
     /**
      * The output message.
      */
-    protected ByteArrayOutputStream mMessage = null;
+    protected ByteArrayOutputStream mMessage;
 
     /**
      * The PDU.
      */
-    private GenericPdu mPdu = null;
+    private GenericPdu mPdu;
 
     /**
      * Current visiting position of the mMessage.
      */
-    protected int mPosition = 0;
+    protected int mPosition;
 
     /**
      * Message compose buffer stack.
      */
-    private BufferStack mStack = null;
+    private BufferStack mStack;
 
     /**
      * Content resolver.
@@ -121,12 +121,12 @@ public class PduComposer {
     /**
      * Header of this pdu.
      */
-    private PduHeaders mPduHeader = null;
+    private PduHeaders mPduHeader;
 
     /**
      * Map of all content type
      */
-    private static SimpleArrayMap<String, Integer> mContentTypeMap = null;
+    private static SimpleArrayMap<String, Integer> mContentTypeMap;
 
     static {
         mContentTypeMap = new SimpleArrayMap<>();
@@ -469,7 +469,7 @@ public class PduComposer {
     }
 
     private EncodedStringValue appendAddressType(final EncodedStringValue address) {
-        EncodedStringValue temp = null;
+        EncodedStringValue temp;
 
         try {
             final int addressType = checkAddressType(address.getString());
@@ -1065,7 +1065,7 @@ public class PduComposer {
                 try {
                     final byte[] buffer = new byte[PDU_COMPOSER_BLOCK_SIZE];
                     cr = mResolver.openInputStream(part.getDataUri());
-                    int len = 0;
+                    int len;
                     while ((len = cr.read(buffer)) != -1) {
                         mMessage.write(buffer, 0, len);
                         mPosition += len;