demo1:獲取螢幕的狀態 ，橫屏與豎屏自動切換fragment

1. publicclassMainActivityextendsActivity{
2. @Override
3. protectedvoid onCreate(Bundle savedInstanceState){
4. super.onCreate(savedInstanceState);
5. setContentView(R.layout.activity_main);
6. //獲取螢幕的寬度和高度 適配不同的fragment
7. DisplayMetrics outMetrics=newDisplayMetrics();
8. getWindowManager
   ().getDefaultDisplay().getMetrics(outMetrics);
9. int width=outMetrics.widthPixels;
10. int height=outMetrics.heightPixels;
11. RelativeLayout layout=(RelativeLayout)findViewById(R.id.layoutId);
12. //要藉助此物件管理fragment物件
13. FragmentManager fm= getFragmentManager();
14. FragmentTransaction ft=fm.beginTransaction();
15. //使用不同的fragment
16. if(
    height>width){
17. ft.replace(R.id.layoutId,newFragment01(),"tag");
18. }else{
19. ft.replace(R.id.layoutId,newFragment02(),"tag");
20. }
21. //可選：將fragment新增到回退棧
22. //ft.addToBackStack(null);
23. ft.commit();
24. }
25. @Override
26. protectedvoid onResume(){
27. super.onResume();
28. //根據tag找到對應的fragment
29. Fragment f=getFragmentManager().findFragmentByTag
    ("tag");
30. Log.i("TAG","f="+f);
31. }
32. }

demo2:Tab+fragment 實現螢幕旋轉儲存資料

1. publicclassMainActivityextendsActivity{
2. ActionBar bar;
3. @Override
4. protectedvoid onCreate(Bundle savedInstanceState){
5. super.onCreate(savedInstanceState);
6. setContentView(R.layout.activity_main);
7. bar=getActionBar();
8. bar.setDisplayShowHomeEnabled(false);
9. bar.setDisplayShowTitleEnabled(false);
10. //設定為tab導航
11. bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
12. //新增tab
13. bar.addTab(bar.newTab().setText("tab01").setTabListener(
14. newMyTabListener(this,Fragment01.class.getName(),"A")));
15. bar.addTab(bar.newTab().setText("tab02").setTabListener(
16. newMyTabListener(this,Fragment02.class.getName(),"B")));
17. }
18. @Override
19. protectedvoid onRestoreInstanceState(Bundle savedInstanceState){
20. super.onRestoreInstanceState(savedInstanceState);
21. if(savedInstanceState!=null){
22. int pos=savedInstanceState.getInt("posKey");
23. bar.setSelectedNavigationItem(pos);
24. }
25. }
26. privateclassMyTabListenerimplementsTabListener{
27. privateContext context;
28. privateString className;
29. privateFragment frg;
30. privateString tag;
31. publicMyTabListener(Context context,String className,String tag){
32. this.context=context;
33. this.className=className;
34. this.tag=tag;
35. //檢測在當前activity是否已經有存在的fragment
36. Fragment frg=getFragmentManager().findFragmentByTag(tag);
37. if(frg!=null&&!frg.isDetached()){
38. FragmentTransaction beginTransaction = getFragmentManager().beginTransaction();
39. beginTransaction.detach(frg);
40. beginTransaction.commit();
41. }
42. }
43. @Override
44. publicvoid onTabSelected(Tab tab,FragmentTransaction ft){
45. if(frg==null){
46. frg=Fragment.instantiate(context, className);
47. ft.add(R.id.layout,frg,tag);
48. }else{
49. ft.attach(frg);
50. }
51. }
52. //沒有選中的那個在旋轉需要解除關聯
53. @Override
54. publicvoid onTabUnselected(Tab tab,FragmentTransaction ft){
55. if(frg!=null){
56. ft.detach(frg);
57. }
58. }
59. @Override
60. publicvoid onTabReselected(Tab tab,FragmentTransaction ft){
61. }
62. }
63. @Override
64. protectedvoid onSaveInstanceState(Bundle outState){
65. super.onSaveInstanceState(outState);
66. int pos=bar.getSelectedTab().getPosition();
67. outState.putInt("posKey", pos);
68. }
69. }