SparseArray中的indexOfValue与ArrayList中indexOf的区别

SparseArray:

/**
     * Returns an index for which {@link #valueAt} would return the
     * specified key, or a negative number if no keys map to the
     * specified value.
     * 
Beware that this is a linear search, unlike lookups by key,
     * and that multiple keys can map to the same value and this will
     * find only one of them.
     * 
Note also that unlike most collections' {@code indexOf} methods,
     * this method compares values using {@code ==} rather than {@code equals}.
     */
    public int indexOfValue(E value) {
        if (mGarbage) {
            gc();
        }

        for (int i = 0; i < mSize; i++)
            if (mValues[i] == value)
                return i;

        return -1;
    }

ArrayList:

    @Override 
    public int indexOf(Object object) {
        Object[] a = array;
        int s = size;
        if (object != null) {
            for (int i = 0; i < s; i++) {
                if (object.equals(a[i])) {
                    return i;
                }
            }
        } else {
            for (int i = 0; i < s; i++) {
                if (a[i] == null) {
                    return i;
                }
            }
        }
        return -1;
    }

SparseArray中的indexOfValue判断不是equals，如果SparseArray中的value为String类型时，indexOfValue(“xxx”)会返回-1。