在主Android Activity中加载Fragment的一般简易方法，来模拟一个微信界面。

2023-11-01 18:51:16

在Fragment的生命周期中，需要重点关注onCreate、onCreateView、onViewCreated。Activity与Fragment生命周期在设计模式上大体一致。

 1 package com.lixu.fragment_test;
 2 
 3 import android.app.Activity;
 4 
 5 import android.app.FragmentManager;
 6 import android.app.FragmentTransaction;
 7 import android.os.Bundle;
 8 import android.view.View;
 9 import android.view.View.OnClickListener;
10 import android.view.Window;
11 import android.widget.ImageView;
12 
13 public class MainActivity extends Activity implements OnClickListener {
14 
15     @Override
16     protected void onCreate(Bundle savedInstanceState) {
17         super.onCreate(savedInstanceState);
18         requestWindowFeature(Window.FEATURE_NO_TITLE);
19         setContentView(R.layout.activity_main);
20         //设置初始界面为“微信”。
21         getweixn();
22 
23         ImageView iv1 = (ImageView) findViewById(R.id.iv1);
24         ImageView iv2 = (ImageView) findViewById(R.id.iv2);
25         ImageView iv3 = (ImageView) findViewById(R.id.iv3);
26         ImageView iv4 = (ImageView) findViewById(R.id.iv4);
27 
28         iv1.setOnClickListener(this);
29         iv2.setOnClickListener(this);
30         iv3.setOnClickListener(this);
31         iv4.setOnClickListener(this);
32 
33     }
34 
35     public void getweixn() {
36         FragmentManager fm = this.getFragmentManager();
37         FragmentTransaction ft = fm.beginTransaction();
38         // 将原有的Activity替换成Fragment。也可以添加到原有之上不覆盖 如：ft.add(R.id.rel, new
39         // Fragment()) ;如果添加的多了会比较耗资源。
40         ft.replace(R.id.fl, new MyFragment1());
41         // 提交
42         ft.commit();
43 
44     }
45 
46     public void gettongxunlu() {
47         //设置Fragment管理器
48         FragmentManager fm = this.getFragmentManager();
49         FragmentTransaction ft = fm.beginTransaction();
50 
51         ft.replace(R.id.fl, new MyFragment2());
52 
53         ft.commit();
54 
55     }
56 
57     public void getfaxian() {
58         FragmentManager fm = this.getFragmentManager();
59         FragmentTransaction ft = fm.beginTransaction();
60 
61         ft.replace(R.id.fl, new MyFragment3());
62 
63         ft.commit();
64 
65     }
66 
67     public void getwo() {
68         FragmentManager fm = this.getFragmentManager();
69         FragmentTransaction ft = fm.beginTransaction();
70 
71         ft.replace(R.id.fl, new MyFragment4());
72 
73         ft.commit();
74 
75     }
76 
77     @Override
78     public void onClick(View v) {
79         switch (v.getId()) {
80         case R.id.iv1:
81             getweixn();
82             break;
83         case R.id.iv2:
84             gettongxunlu();
85             break;
86         case R.id.iv3:
87             getfaxian();
88             break;
89         case R.id.iv4:
90             getwo();
91             break;
92 
93         default:
94             break;
95         }
96     }
97 
98 }

 1 package com.lixu.fragment_test;
 2 
 3 
 4 import android.app.Fragment;
 5 import android.os.Bundle;
 6 
 7 import android.view.LayoutInflater;
 8 import android.view.View;
 9 import android.view.ViewGroup;
10 import android.widget.ImageView;
11 
12 class MyFragment1 extends Fragment {
13 
14     @Override
15     public void onCreate(Bundle savedInstanceState) {
16         super.onCreate(savedInstanceState);
17     }
18 
19     // 创建view   也可以直接在这里面获取view中的控件。
20     @Override
21     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
22 
23         View view = inflater.inflate(R.layout.image, null);
24 
25         return view;
26     }
27 
28     // 创建view完毕  可以直接在onCreateView中获取view中控件。
29     @Override
30     public void onViewCreated(View view, Bundle savedInstanceState) {
31         super.onViewCreated(view, savedInstanceState);
32 
33         ImageView iv = (ImageView) view.findViewById(R.id.iv);
34         iv.setImageResource(R.drawable.weixinjiemian);
35     }
36 }

  1 package com.lixu.fragment_test;
  2 
  3 import java.util.ArrayList;
  4 import java.util.HashMap;
  5 
  6 import android.app.Fragment;
  7 import android.content.Context;
  8 import android.graphics.Color;
  9 import android.os.Bundle;
 10 
 11 import android.view.LayoutInflater;
 12 import android.view.View;
 13 import android.view.ViewGroup;
 14 import android.widget.ArrayAdapter;
 15 import android.widget.ListView;
 16 import android.widget.TextView;
 17 
 18 class MyFragment2 extends Fragment {
 19     private static final String TYPE = "type";
 20     private static final String DATE = "date";
 21     private static final int GROUP = -1;
 22     private static final int ITEM = -2;
 23 
 24     private ArrayList<HashMap<String, Object>> item = null;
 25 
 26     @Override
 27     public void onCreate(Bundle savedInstanceState) {
 28         super.onCreate(savedInstanceState);
 29 
 30     }
 31 
 32     // 创建view
 33     @Override
 34     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 35 
 36         View view = inflater.inflate(R.layout.list, null);
 37 
 38         return view;
 39     }
 40 
 41     // 创建view完毕
 42     @Override
 43     public void onViewCreated(View view, Bundle savedInstanceState) {
 44         super.onViewCreated(view, savedInstanceState);
 45 
 46         ListView lv = (ListView) view.findViewById(R.id.lv);
 47         MyAdaper adapter = new MyAdaper(getActivity(), -1);
 48 
 49         item = new ArrayList<HashMap<String, Object>>();
 50 
 51         String[] groups = { "家人", "朋友", "同学", "同事" };
 52         String[] date = { "张三", "李四", "王五", "狗儿" };
 53         for (String str : groups) {
 54             HashMap<String, Object> group_map = new HashMap<String, Object>();
 55 
 56             group_map.put(TYPE, GROUP);
 57             group_map.put(DATE, str);
 58             item.add(group_map);
 59             for (String n : date) {
 60 
 61                 HashMap<String, Object> date_map = new HashMap<String, Object>();
 62 
 63                 date_map.put(TYPE, ITEM);
 64                 date_map.put(DATE, n);
 65                 item.add(date_map);
 66 
 67             }
 68 
 69         }
 70         lv.setAdapter(adapter);
 71     }
 72 
 73     private class MyAdaper extends ArrayAdapter {
 74         private LayoutInflater flater = null;
 75         private Context context;
 76 
 77         public MyAdaper(Context context, int resource) {
 78             super(context, resource);
 79             this.context = context;
 80             flater = LayoutInflater.from(context);
 81         }
 82 
 83         @Override
 84         public int getCount() {
 85             return item.size();
 86         }
 87 
 88         @Override
 89         public int getItemViewType(int position) {
 90             HashMap<String, Object> map = item.get(position);
 91             return (Integer) map.get(TYPE);
 92         }
 93 
 94         @Override
 95         public int getViewTypeCount() {
 96 
 97             return 2;
 98         }
 99 
100         @Override
101         public View getView(int position, View convertView, ViewGroup parent) {
102             int type = getItemViewType(position);
103             // 根据不同的view type加载不同的布局文件。
104             switch (type) {
105             case GROUP:
106 
107                 convertView = flater.inflate(android.R.layout.simple_list_item_1, null);
108                 TextView tv1 = (TextView) convertView.findViewById(android.R.id.text1);
109                 tv1.setText(item.get(position).get(DATE) + "");
110                 tv1.setBackgroundColor(Color.RED);
111                 tv1.setTextSize(20);
112 
113                 break;
114             case ITEM:
115                 convertView = flater.inflate(android.R.layout.simple_list_item_1, null);
116                 TextView tv2 = (TextView) convertView.findViewById(android.R.id.text1);
117                 tv2.setText(item.get(position).get(DATE) + "");
118 
119                 break;
120 
121             default:
122                 break;
123             }
124 
125             return convertView;
126         }
127 
128     }
129 }

 1 package com.lixu.fragment_test;
 2 
 3 
 4 import android.app.Fragment;
 5 import android.os.Bundle;
 6 
 7 import android.view.LayoutInflater;
 8 import android.view.View;
 9 import android.view.ViewGroup;
10 import android.widget.ImageView;
11 
12 class MyFragment3 extends Fragment {
13 
14     @Override
15     public void onCreate(Bundle savedInstanceState) {
16         super.onCreate(savedInstanceState);
17     }
18 
19     // 创建view
20     @Override
21     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
22 
23         View view = inflater.inflate(R.layout.image, null);
24 
25         return view;
26     }
27 
28     // 创建view完毕
29     @Override
30     public void onViewCreated(View view, Bundle savedInstanceState) {
31         super.onViewCreated(view, savedInstanceState);
32 
33         ImageView iv = (ImageView) view.findViewById(R.id.iv);
34         iv.setImageResource(R.drawable.faxianjiemian);
35     }
36 }

 1 package com.lixu.fragment_test;
 2 
 3 
 4 import android.app.Fragment;
 5 import android.os.Bundle;
 6 
 7 import android.view.LayoutInflater;
 8 import android.view.View;
 9 import android.view.ViewGroup;
10 import android.widget.ImageView;
11 
12 class MyFragment4 extends Fragment {
13 
14     @Override
15     public void onCreate(Bundle savedInstanceState) {
16         super.onCreate(savedInstanceState);
17     }
18 
19     // 创建view
20     @Override
21     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
22 
23         View view = inflater.inflate(R.layout.image, null);
24 
25         return view;
26     }
27 
28     // 创建view完毕
29     @Override
30     public void onViewCreated(View view, Bundle savedInstanceState) {
31         super.onViewCreated(view, savedInstanceState);
32 
33         ImageView iv = (ImageView) view.findViewById(R.id.iv);
34         iv.setImageResource(R.drawable.wojiemian);
35     }
36 }

xml文件：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:id="@+id/LinearLayout1"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:orientation="vertical"
 7     tools:context="com.lixu.fragment_test.MainActivity" >
 8 
 9     <FrameLayout
10         android:id="@+id/fl"
11         android:layout_width="match_parent"
12         android:layout_height="wrap_content"
13         android:layout_weight="1" >
14     </FrameLayout>
15 
16     <LinearLayout
17         android:id="@+id/linearlayout"
18         android:layout_width="wrap_content"
19         android:layout_height="wrap_content"
20         android:orientation="horizontal" >
21 
22         <ImageView
23             android:id="@+id/iv1"
24             android:layout_width="90dp"
25             android:layout_height="60dp"
26             android:layout_weight="1"
27             android:background="@drawable/weixin" />
28 
29         <ImageView
30             android:id="@+id/iv2"
31             android:layout_width="90dp"
32             android:layout_height="60dp"
33             android:layout_weight="1"
34             android:background="@drawable/tongxunlu" />
35 
36         <ImageView
37             android:id="@+id/iv3"
38             android:layout_width="90dp"
39             android:layout_height="60dp"
40             android:layout_weight="1"
41             android:background="@drawable/faxian" />
42 
43         <ImageView
44             android:id="@+id/iv4"
45             android:layout_width="90dp"
46             android:layout_height="60dp"
47             android:layout_weight="1"
48             android:background="@drawable/wo" />
49     </LinearLayout>
50 
51 </LinearLayout>

1 <?xml version="1.0" encoding="utf-8"?>
2 <ImageView xmlns:android="http://schemas.android.com/apk/res/android"
3     android:id="@+id/iv"
4     android:layout_width="match_parent"
5     android:layout_height="match_parent" >
6 
7 </ImageView>

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical" >
 6 
 7     <ListView
 8         android:id="@+id/lv"
 9         android:layout_width="match_parent"
10         android:layout_height="match_parent" >
11     </ListView>
12 
13 </LinearLayout>

运行效果图，演示为主，效果为辅，图片有点不真实，哈哈。

在主Android Activity中加载Fragment的一般简易方法，来模拟一个微信界面。

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