Simplify unused code and use vector icons (getodk#1742)

* Removed redundant casts
* Removed unused file types
* Replaced ic_download.png icon with vector
* Replaced ic_folder.png icon with vector

collect_app/src/main/java/org/odk/collect/android/adapters/FileArrayAdapter.java

@@ -75,27 +75,22 @@ public View getView(int position, View convertView, ViewGroup parent) {
                         .format(new Date(o.getDate().getValue()));
             }
 
-            ImageView iv = (ImageView) v.findViewById(R.id.image);
-            CheckBox cb = (CheckBox) v.findViewById(R.id.checkbox);
+            ImageView iv = v.findViewById(R.id.image);
+            CheckBox cb = v.findViewById(R.id.checkbox);
 
-            if (o.getType() == 1) {
-                Drawable d = ContextCompat.getDrawable(context, R.drawable.ic_download);
+            if (o.getType() == DriveListItem.FILE) {
+                Drawable d = ContextCompat.getDrawable(context, R.drawable.ic_file_download);
                 iv.setImageDrawable(d);
                 cb.setVisibility(View.VISIBLE);
             }
-            if (o.getType() == 3) {
-                Drawable d = ContextCompat.getDrawable(context, R.drawable.ic_back);
-                iv.setImageDrawable(d);
-                cb.setVisibility(View.GONE);
-            }
-            if (o.getType() == 2 || o.getType() == 4 || o.getType() == 5) {
+            if (o.getType() == DriveListItem.DIR) {
                 Drawable d = ContextCompat.getDrawable(context, R.drawable.ic_folder);
                 iv.setImageDrawable(d);
                 cb.setVisibility(View.GONE);
             }
 
-            TextView t1 = (TextView) v.findViewById(R.id.text1);
-            TextView t2 = (TextView) v.findViewById(R.id.text2);
+            TextView t1 = v.findViewById(R.id.text1);
+            TextView t2 = v.findViewById(R.id.text2);
 
             if (t1 != null) {
                 t1.setText(o.getName());

collect_app/src/main/java/org/odk/collect/android/logic/DriveListItem.java

@@ -34,12 +34,8 @@ public class DriveListItem implements Comparable<DriveListItem>, Parcelable {
     private DateTime date;
     private int type;
 
-
     public static final int FILE = 1;
     public static final int DIR = 2;
-    public static final int UP = 3;
-    public static final int MY_DRIVE = 4;
-    public static final int SHARED_WITH_ME = 5;
 
     public DriveListItem(String n, String d, DateTime dt, String p, String img, int type,
             String driveId, String parentId) {

collect_app/src/main/res/drawable/ic_file_download.xml

@@ -0,0 +1,4 @@
+<vector android:height="36dp" android:viewportHeight="24.0"
+    android:viewportWidth="24.0" android:width="36dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M19,9h-4V3H9v6H5l7,7 7,-7zM5,18v2h14v-2H5z"/>
+</vector>

collect_app/src/main/res/drawable/ic_folder.xml

@@ -0,0 +1,4 @@
+<vector android:height="36dp" android:viewportHeight="24.0"
+    android:viewportWidth="24.0" android:width="36dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M10,4H4c-1.1,0 -1.99,0.9 -1.99,2L2,18c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2V8c0,-1.1 -0.9,-2 -2,-2h-8l-2,-2z"/>
+</vector>