fix bug,imp project.

[Blankeer]

remove *.iml files.
add .gitignore file.
add setError() method.
fix imageId == NO_ID crash bug.
imp code.

[cheng2016]

private void show(int layoutId) {
        for (View view : mLayouts.values()) {
            view.setVisibility(GONE);
        }
        layout(layoutId).setVisibility(VISIBLE);
    }

应改为，防止部分布局GONE之后重新layotu导致的部分问题

private void show(int layoutId) {
        for (View view : mLayouts.values()) {
            view.setVisibility(INVISIBLE);
        }
        layout(layoutId).setVisibility(VISIBLE);
    }