Converting long item IDs to int

> Items ids were already being typecasted to int when being bound on the UI
> Using a consistent type allow better use of platform data-structures
> Adding IntArray and IntSet as a replacement for various Collection classes

Change-Id: Id3c650ed2420c2bfca3bd7671d2b705b56112371

src/com/android/launcher3/util/IntSparseArrayMap.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3.util;
+
+import android.util.SparseArray;
+
+import java.util.Iterator;
+
+/**
+ * Extension of {@link SparseArray} with some utility methods.
+ */
+public class IntSparseArrayMap<E> extends SparseArray<E> implements Iterable<E> {
+
+    public boolean containsKey(int key) {
+        return indexOfKey(key) >= 0;
+    }
+
+    public boolean isEmpty() {
+        return size() <= 0;
+    }
+
+    @Override
+    public IntSparseArrayMap<E> clone() {
+        return (IntSparseArrayMap<E>) super.clone();
+    }
+
+    @Override
+    public Iterator<E> iterator() {
+        return new ValueIterator();
+    }
+
+    @Thunk class ValueIterator implements Iterator<E> {
+
+        private int mNextIndex = 0;
+
+        @Override
+        public boolean hasNext() {
+            return mNextIndex < size();
+        }
+
+        @Override
+        public E next() {
+            return valueAt(mNextIndex ++);
+        }
+
+        @Override
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+    }
+}