小议ActionBar

    public void createAction() {
        // to create a SpinnerAdapter
        SpinnerAdapter adapter = ArrayAdapter.createFromResource(this,
                R.array.style_choice,
                android.R.layout.simple_spinner_dropdown_item);
        android.app.ActionBar actionBar = getActionBar();

        // to set the style
        actionBar.setDisplayShowHomeEnabled(false);
        actionBar.setDisplayShowTitleEnabled(false);
        Resources r = getResources();

        Drawable myDrawable = r.getDrawable(R.drawable.gradient_header);

        actionBar.setBackgroundDrawable(myDrawable);

        // to set the mode NAVIGATION_MODE_LIST
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
        // to add a listener
        actionBar.setListNavigationCallbacks(adapter, new DropDownListenser());
    }

    /**
     * 实现 ActionBar.OnNavigationListener接口
     */
    class DropDownListenser implements OnNavigationListener {
        // 得到和SpinnerAdapter里一致的字符数组
        String[] listNames = getResources()
                .getStringArray(R.array.style_choice);

        /* 当选择下拉菜单项的时候，将Activity中的内容置换为对应的Fragment */
        public boolean onNavigationItemSelected(int itemPosition, long itemId) {
            if (itemPosition == 1) {
                pager.edit().putString("name", "古典样式").commit();
                Intent intent = new Intent().setClass(MainHomeActivity.this,
                        ClassicalMainActivity.class);
                startActivity(intent);
                finish();
            } else {
                pager.edit().putString("name", "现代样式").commit();
            }
            return true;
        }
    }