android菜鸟学习笔记27----Fragment的简单使用

1.Fragment的生命周期：

简单在新建一个MyFragment继承自Fragment，重写各个生命周期回调方法，各个方法中直接输出标识相关函数被调用的信息。

重写MainActivity的各个生命周期回调方法，同样输出标识信息。

MyFragment.java：

  1 public class MyFragment extends Fragment {
  2 
  3       @Override
  4 
  5       public void onActivityCreated(Bundle savedInstanceState) {
  6 
  7            // TODO Auto-generated method stub
  8 
  9            super.onActivityCreated(savedInstanceState);
 10 
 11            Log.i("FRAGMENT","onActivityCreated()");
 12 
 13       }
 14 
 15       @Override
 16 
 17       public View onCreateView(LayoutInflater inflater, ViewGroup container,
 18 
 19                  Bundle savedInstanceState) {
 20 
 21            // TODO Auto-generated method stub
 22 
 23            Log.i("FRAGMENT","onCreateView()");
 24 
 25            TextView textView = new TextView(getActivity());
 26 
 27            textView.setText("This is a fragment");
 28 
 29            return textView;
 30 
 31       }
 32 
 33       @Override
 34 
 35       public void onDestroyView() {
 36 
 37            // TODO Auto-generated method stub
 38 
 39            super.onDestroyView();
 40 
 41            Log.i("FRAGMENT","onDestroyView()");
 42 
 43       }
 44 
 45       @Override
 46 
 47       public void onAttach(Activity activity) {
 48 
 49            // TODO Auto-generated method stub
 50 
 51            super.onAttach(activity);
 52 
 53            Log.i("FRAGMENT","onAttach()");
 54 
 55       }
 56 
 57       @Override
 58 
 59       public void onCreate(Bundle savedInstanceState) {
 60 
 61            // TODO Auto-generated method stub
 62 
 63            super.onCreate(savedInstanceState);
 64 
 65            Log.i("FRAGMENT","onCreate()");
 66 
 67       }
 68 
 69       @Override
 70 
 71       public void onStart() {
 72 
 73             // TODO Auto-generated method stub
 74 
 75            super.onStart();
 76 
 77            Log.i("FRAGMENT","onStart()");
 78 
 79       }
 80 
 81       @Override
 82 
 83       public void onResume() {
 84 
 85            // TODO Auto-generated method stub
 86 
 87            super.onResume();
 88 
 89            Log.i("FRAGMENT","onResume()");
 90 
 91       }
 92 
 93       @Override
 94 
 95       public void onPause() {
 96 
 97            // TODO Auto-generated method stub
 98 
 99            super.onPause();
100 
101            Log.i("FRAGMENT","onPause()");
102 
103       }
104 
105       @Override
106 
107       public void onStop() {
108 
109            // TODO Auto-generated method stub
110 
111            super.onStop();
112 
113            Log.i("FRAGMENT","onStop()");
114 
115       }
116 
117       @Override
118 
119       public void onDestroy() {
120 
121            // TODO Auto-generated method stub
122 
123            super.onDestroy();
124 
125            Log.i("FRAGMENT","onDestroy()");
126 
127       }
128 
129       @Override
130 
131       public void onDetach() {
132 
133            // TODO Auto-generated method stub
134 
135            super.onDetach();
136 
137            Log.i("FRAGMENT","onDetach()");
138 
139       }
140 
141 }

注意：onCreateView()方法中需返回一个View对象。

MainActivity.java:

 1 public class MainActivity extends ActionBarActivity {
 2 
 3     @Override
 4 
 5     protected void onCreate(Bundle savedInstanceState) {
 6 
 7         super.onCreate(savedInstanceState);
 8 
 9         setContentView(R.layout.activity_main);
10 
11         Log.i("ACTIVITY","onCreate()");
12 
13     }
14 
15       @Override
16 
17       protected void onStop() {
18 
19            // TODO Auto-generated method stub
20 
21            super.onStop();
22 
23            Log.i("ACTIVITY","onStop()");
24 
25       }
26 
27       @Override
28 
29       protected void onDestroy() {
30 
31            // TODO Auto-generated method stub
32 
33            super.onDestroy();
34 
35            Log.i("ACTIVITY","onDestroy()");
36 
37       }
38 
39       @Override
40 
41       protected void onPause() {
42 
43            // TODO Auto-generated method stub
44 
45            super.onPause();
46 
47            Log.i("ACTIVITY","onPause()");
48 
49       }
50 
51       @Override
52 
53       protected void onResume() {
54 
55            // TODO Auto-generated method stub
56 
57            super.onResume();
58 
59            Log.i("ACTIVITY","onResume()");
60 
61       }
62 
63       @Override
64 
65       protected void onStart() {
66 
67            // TODO Auto-generated method stub
68 
69            super.onStart();
70 
71            Log.i("ACTIVITY","onStart()");
72 
73       }
74 
75       @Override
76 
77       protected void onRestart() {
78 
79            // TODO Auto-generated method stub
80 
81            super.onRestart();
82 
83            Log.i("ACTIVITY","onRestart()");
84 
85       }
86 
87 }

布局文件：

1 <fragment
2 
3         android:id="@+id/frag"
4 
5         android:name="cn.csc.fragment.MyFragment"
6 
7         android:layout_width="wrap_content"
8 
9         android:layout_height="wrap_content"/>

注意，添加的fragment需要通过name属性指定自己新建的fragment的权限定名。

运行结果：

按下模拟器的BACK按钮：

中间插入了dalvik的垃圾回收，不过整体的顺序是没有改变的：

整个生命周期各个回调函数的调用过程如下：

显示到前台：

MyFragment onAttach() 附加到activity上

MyFragment onCreate() fragment创建

MyFragment onCreateView() fragment创建自己的视图

MainActivity onCreate() activity创建

MyFragment onActivityCreated()

MainActivity onStart()

MyFragment onStart()

MainActivity onResume()

MyFragment onResume()

按后退键

MyFragment onPause()

MainActivity onPause()

MyFragment onStop()

MainActivity onStop()

MyFragment onDestoryView() 销毁掉自己的视图

MyFragment onDestory()

MyFragment onDetach() 解除和activity的关系

MainActivity onDetory()

2.一个简单的两个Fragmet联系的示例，点击其中一个另一个发生变化：

1)新建MyFragment继承自ListFragment:

public class MyFragment extends ListFragment {

 

      @Override

      public void onActivityCreated(Bundle savedInstanceState) {

           // TODO Auto-generated method stub

           super.onActivityCreated(savedInstanceState);

           setListAdapter(new ArrayAdapter<String>(getActivity(),

           android.R.layout.simple_list_item_activated_1, android.R.id.text1,

           new String[]{"6:00","6:30","7:20","8:00","8:40"}));

      }

      @Override

      public void onListItemClick(ListView l, View v, int position, long id) {

           // TODO Auto-generated method stub

           super.onListItemClick(l, v, position, id);

           //设置为单选模式，单击选中

           getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);

           getListView().setItemChecked(position, true);

           FragmentManager fm = getFragmentManager();

           FragmentTransaction ft = fm.beginTransaction();

           Fragment fr = new TmpFragment(position);

           ft.replace(R.id.frame, fr);

           ft.commit();

      }

}

2)新建TmpFragment继承自Fragment:

 1 public class TmpFragment extends Fragment {
 2 
 3       private int index;
 4 
 5       private static String[] items = new String[]{"起床洗漱","打拳散步","吃早饭","等公交","打卡"};
 6 
 7       public TmpFragment(int index) {
 8 
 9            super();
10 
11            this.index = index;
12 
13       }
14 
15       @Override
16 
17       public View onCreateView(LayoutInflater inflater, ViewGroup container,
18 
19                  Bundle savedInstanceState) {
20 
21            // TODO Auto-generated method stub
22 
23            TextView tv = new TextView(getActivity());
24 
25            tv.setText(items[index]);
26 
27            return tv;
28 
29       }
30 
31 }

3)布局文件：

 1 <fragment
 2 
 3         android:id="@+id/frag"
 4 
 5         android:name="cn.csc.fragment1.MyFragment"
 6 
 7         android:layout_width="0dp"
 8 
 9         android:layout_height="match_parent"
10 
11         android:layout_weight="1"
12 
13         />
14 
15     <FrameLayout
16 
17         android:id="@+id/frame"
18 
19         android:layout_width="0dp"
20 
21         android:layout_height="wrap_content"
22 
23         android:layout_weight="1">
24 
25 </FrameLayout>

4)运行结果：

以上就是Fragment的简单学习，需要时再认真学下……