yfujiki / android-dragreordersample Goto Github PK

    fun moveItem(from: Int, to: Int) {
        val fromEmoji = emojis[from]
        emojis.removeAt(from)
        emojis.add(to, fromEmoji)    
    }

@Test
    public void testMoveItem() {
        List<Integer> list = Arrays.asList(0, 1, 2, 3, 4, 5);
        assertEquals(
                Arrays.asList(1, 0, 2, 3, 4, 5),
                moveItem(list, 0, 1));
        assertEquals(
                Arrays.asList(1, 2, 0, 3, 4, 5),
                moveItem(list, 0, 2));
        assertEquals(
                Arrays.asList(1, 2, 3, 4, 5, 0),
                moveItem(list, 0, 5));
        assertEquals(
                Arrays.asList(0, 1, 2, 3, 5, 4),
                moveItem(list, 5, 4));
        assertEquals(
                Arrays.asList(5, 0, 1, 2, 3, 4),
                moveItem(list, 5, 0));
        assertEquals(
                Arrays.asList(0, 1, 2, 4, 3, 5),
                moveItem(list, 3, 4));
        assertEquals(
                Arrays.asList(0, 1, 2, 4, 3, 5),
                moveItem(list, 4, 3));
    }

    public <T> List<T> moveItem(List<T> data, int from, int to) {
        data = new ArrayList<>(data);
        T item = data.get(from);
        data.remove(from);
        data.add(to, item);
        return data;
    }