关于Android 在Activity中动态得到frament的控件

Fragment写好后，
要在哪个 Activity添加fragment如下做：

在Activity 声明 private ArrayList fmList;

初始化界面方法中写：

        fm1 = new Fragment1();
        fm2 = new Fragment2();
        fmList = new ArrayList<Fragment>();
        fmList.add(fm1);
        fmList.add(fm2);

页面的切换要做

    private ViewPager viewPager;
    private BaseFragment currFragment;

    viewPager.setAdapter(pagerAdapter);
    // viewPager.setOnPageChangeListener(pageChangeListener);
    currFragment = (BaseFragment)pagerAdapter.getItem(0);
    showNowTab(0);

    private FragmentPagerAdapter pagerAdapter = new FragmentPagerAdapter(
            getSupportFragmentManager()) {

        @Override
        public int getCount() {
            return fmList.size();
        }

        @Override
        public Fragment getItem(int arg0) {
            return fmList.get(arg0);
        }
    };