Fragment保持状态切换

 1     /**
 2      * Fragment跳转
 3      * @param fm
 4      * @param fragmentClass
 5      * @param tag
 6      * @param args
 7      */
 8     public void turnToFragment(Class<? extends Fragment> fromFragmentClass, Class<? extends Fragment> toFragmentClass, Bundle args) {
 9         
10         FragmentManager fm = getSupportFragmentManager();
11         //被切换的Fragment标签
12         String fromTag = fromFragmentClass.getSimpleName();
13         //切换到的Fragment标签
14         String toTag = toFragmentClass.getSimpleName();
15         //查找切换的Fragment
16         Fragment fromFragment = fm.findFragmentByTag(fromTag);
17         Fragment toFragment = fm.findFragmentByTag(toTag);
18         //如果要切换到的Fragment不存在，则创建
19         if (toFragment == null) {
20             try {
21                 toFragment = toFragmentClass.newInstance();
22                 toFragment.setArguments(args);
23             } catch (java.lang.InstantiationException e) {
24                 e.printStackTrace();
25             } catch (IllegalAccessException e) {
26                 e.printStackTrace();
27             }
28         }
29         //如果有参数传递，
30         if( args != null && !args.isEmpty() ) {
31             toFragment.getArguments().putAll(args);
32         }
33         //Fragment事务
34         FragmentTransaction ft = fm.beginTransaction();
35         //设置Fragment切换效果
36         ft.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out,
37                 android.R.anim.fade_in, android.R.anim.fade_out);
38         /**
39          * 如果要切换到的Fragment没有被Fragment事务添加，则隐藏被切换的Fragment，添加要切换的Fragment
40          * 否则，则隐藏被切换的Fragment，显示要切换的Fragment
41          */
42         if( !toFragment.isAdded()) {
43             ft.hide(fromFragment).add(R.id.content_frame, toFragment, toTag);
44         } else {
45             ft.hide(fromFragment).show(toFragment);
46         }
47         //添加到返回堆栈
48 //        ft.addToBackStack(tag);
49         //不保留状态提交事务
50         ft.commitAllowingStateLoss();
51     }