Add documentation.

Author: Sam1301

app/src/main/java/com/zulip/android/activities/ZulipActivity.java

@@ -942,9 +942,6 @@ protected void onActivityResult(int requestCode, int resultCode, Intent data) {
             // activity transition animation
             ActivityTransitionAnim.transition(ZulipActivity.this);
         }
-
-        // TODO: rearrange code
-        // in else if upload file sent and show notification for it
         else if (requestCode == REQUEST_PICK_FILE && resultCode == RESULT_OK) {
             List<Uri> fileUris = new ArrayList<>();
             if (data.getData() != null) {
@@ -1135,7 +1132,8 @@ public void onProgressUpdate(int percentage, String progress, int notificationId
     private NotificationCompat.Builder mBuilder;
 
     /**
-     * TODO: add description
+     * Modifies notification {@link Notifications} of specifies {@param notificationId}
+     * and sets its {@param content}.
      *
      * @param notificationId
      * @param content
@@ -1158,7 +1156,8 @@ private void setNotification(int notificationId, String content) {
     }
 
     /**
-     * TODO: add description
+     * Updates upload notification with passed percentage {@param percentage} and progress string
+     * {@param progress} as content.
      *
      * @param notificationId
      * @param percentage
@@ -1174,7 +1173,7 @@ private void progressNotification(int notificationId, int percentage, String pro
     }
 
     /**
-     * TODO: add description
+     * Shows success notification.
      *
      * @param notificationId
      * @param content

app/src/main/java/com/zulip/android/networking/UploadProgressRequest.java

@@ -12,7 +12,8 @@
 import okio.BufferedSink;
 
 /**
- * TODO: add description
+ * Decorated retrofit RequestBody to intercept progress during network call.
+ * Implement UploadCallbacks interface {@link UploadCallbacks} to receive progress update.
  */
 
 public class UploadProgressRequest extends RequestBody {

app/src/main/java/com/zulip/android/util/ListDialog.java

@@ -12,14 +12,15 @@
 import com.zulip.android.R;
 
 /**
- * TODO: add description
+ * List dialog for picking option of upload (camera or file).
+ *
+ * The activity that creates an instance of this dialog fragment must
+ * implement ListDialogListener interface {@link ListDialogListener} in order to receive event callbacks.
+ * Each method passes the DialogFragment in case the host needs to query it.
  */
 
 public class ListDialog extends DialogFragment {
 
-    /* The activity that creates an instance of this dialog fragment must
-     * implement this interface in order to receive event callbacks.
-     * Each method passes the DialogFragment in case the host needs to query it. */
     public interface ListDialogListener {
         void onDialogPhotoClick(DialogFragment dialog);
         void onDialogFileClick(DialogFragment dialog);