增加折叠与展开的监听

增加折叠与展开的监听
使用方法
foldNavScrollLayout.setOnFoldNavListener(new IFoldNavListener() {
@OverRide
public void onNavFoldBegin() {
Log.i("navfold","onNavFoldBegin");
Toast.makeText(MainActivity.this,"onNavFoldBegin",Toast.LENGTH_SHORT).show();
}

        @Override
        public void onNavFoldFinish() {
            Log.i("navfold","onNavFoldFinish");
            Toast.makeText(MainActivity.this,"onNavFoldFinish",Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onNavExpandBegin() {
            Log.i("navfold","onNavExpandBegin");
            Toast.makeText(MainActivity.this,"onNavExpandBegin",Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onNavExpandFinish() {
            Log.i("navfold","onNavExpandFinish");
            Toast.makeText(MainActivity.this,"onNavExpandFinish",Toast.LENGTH_SHORT).show();
        }
    });