AsyncTask 异步任务 的用法（并且使用ORMlite关系数据库）；

 1 package com.lixu.asynctask;
 2 
 3 import com.j256.ormlite.field.DatabaseField;
 4 import com.j256.ormlite.table.DatabaseTable;
 5 
 6 @DatabaseTable(tableName = "users")
 7 public class User {
 8     public User() {
 9 
10     }
11 
12 
13     
14 
15     @Override
16     public String toString() {
17         return "id" + user_id + "," + ",姓名：" + name + ",年龄：" + age + ",性别：" + sex+",班级是："+aclass;
18     }
19 
20     
21 
22 
23     public int getUser_id() {
24         return user_id;
25     }
26 
27     public void setUser_id(int user_id) {
28         this.user_id = user_id;
29     }
30 
31     public String getName() {
32         return name;
33     }
34 
35     public void setName(String name) {
36         this.name = name;
37     }
38 
39     public int getAge() {
40         return age;
41     }
42 
43     public void setAge(int age) {
44         this.age = age;
45     }
46 
47     public String getSex() {
48         return sex;
49     }
50 
51     public void setSex(String sex) {
52         this.sex = sex;
53     }
54 
55     public AClass getAclass() {
56         return aclass;
57     }
58 
59     public void setAclass(AClass aclass) {
60         this.aclass = aclass;
61     }
62 
63     public User(int user_id, String name, int age, String sex, AClass aclass) {
64         super();
65         this.user_id = user_id;
66         this.name = name;
67         this.age = age;
68         this.sex = sex;
69         this.aclass = aclass;
70     }
71 
72 
73  
74     @DatabaseField(id=true,columnName = "user_id")
75     public int user_id;
76 
77     @DatabaseField(columnName = "name")
78     public String name;
79 
80     @DatabaseField(columnName = "age")
81     public int age;
82     @DatabaseField(columnName = "sex")
83     public String sex;
84     @DatabaseField(canBeNull = false, foreign = true, foreignAutoRefresh = true)
85     public AClass aclass;
86 
87 }

 1 package com.lixu.asynctask;
 2 
 3 import com.j256.ormlite.dao.ForeignCollection;
 4 import com.j256.ormlite.field.DataType;
 5 import com.j256.ormlite.field.DatabaseField;
 6 import com.j256.ormlite.field.ForeignCollectionField;
 7 import com.j256.ormlite.table.DatabaseTable;
 8 
 9 @DatabaseTable(tableName = "classes")
10 public class AClass {
11 
12     public AClass(long id, String name, ForeignCollection<User> user) {
13         super();
14         this.id = id;
15         this.name = name;
16         this.user = user;
17     }
18 
19     @Override
20     public String toString() {
21         return "id" + id + "班级名：" + name;
22     }
23 
24     public long getId() {
25         return id;
26     }
27 
28     public void setId(long id) {
29         this.id = id;
30     }
31 
32     public String getName() {
33         return name;
34     }
35 
36     public void setName(String name) {
37         this.name = name;
38     }
39 
40     public ForeignCollection<User> getUser() {
41         return user;
42     }
43 
44     public void setUser(ForeignCollection<User> user) {
45         this.user = user;
46     }
47 
48     @DatabaseField(id = true)
49     public long id;
50 
51     @DatabaseField(dataType = DataType.STRING)
52     public String name;
53 
54     @ForeignCollectionField(eager = false)
55     public ForeignCollection<User> user = null;
56 
57     public AClass() {
58 
59     }
60 
61 }

 1 package com.lixu.asynctask;
 2 
 3 import com.j256.ormlite.android.apptools.OrmLiteSqliteOpenHelper;
 4 import com.j256.ormlite.dao.Dao;
 5 import com.j256.ormlite.support.ConnectionSource;
 6 import com.j256.ormlite.table.TableUtils;
 7 import android.content.Context;
 8 import android.database.sqlite.SQLiteDatabase;
 9 import android.database.sqlite.SQLiteDatabase.CursorFactory;
10 import android.util.Log;
11 
12 public class MyORMlite extends OrmLiteSqliteOpenHelper {
13     private static String DATABASENAME = "lixu.db";
14     private static int DATABASEVERSION = 1;
15 
16     private static MyORMlite mMyORMlite = null;
17     private Dao<User, Integer> muserDao = null;
18     private Dao<AClass, Integer> mclassDao = null;
19 
20     public MyORMlite(Context context, String databaseName, CursorFactory factory, int databaseVersion) {
21         super(context, databaseName, factory, databaseVersion);
22     }
23 
24     public static MyORMlite getInstance(Context context) {
25         if (mMyORMlite == null) {
26             mMyORMlite = new MyORMlite(context, DATABASENAME, null, DATABASEVERSION);
27         }
28         return mMyORMlite;
29 
30     }
31 
32     @Override
33     public void onCreate(SQLiteDatabase arg0, ConnectionSource arg1) {
34 
35         try {
36             TableUtils.createTableIfNotExists(arg1, User.class);
37             TableUtils.createTableIfNotExists(arg1, AClass.class);
38             Log.d("MyORMlite", "被创建");
39         } catch (Exception e) {
40             e.printStackTrace();
41         }
42     }
43 
44     public Dao<User, Integer> getuserDao() {
45         if (muserDao == null) {
46             try {
47                 muserDao = getDao(User.class);
48             } catch (Exception e) {
49                 e.printStackTrace();
50             }
51         }
52         return muserDao;
53     }
54 
55     public Dao<AClass, Integer> getclassDao() {
56         if (mclassDao == null) {
57             try {
58                 mclassDao = getDao(AClass.class);
59             } catch (Exception e) {
60                 e.printStackTrace();
61             }
62         }
63         return mclassDao;
64     }
65 
66     @Override
67     public void close() {
68         super.close();
69         muserDao = null;
70         mclassDao = null;
71         
72     }
73 
74     @Override
75     public void onUpgrade(SQLiteDatabase arg0, ConnectionSource arg1, int arg2, int arg3) {
76 
77     }
78 
79 }

  1 package com.lixu.asynctask;
  2 
  3 import java.sql.SQLException;
  4 import java.util.List;
  5 
  6 import com.j256.ormlite.dao.Dao;
  7 import com.lixu.asynctask.AClass;
  8 import com.lixu.asynctask.User;
  9 import com.lixu.asynctask.MyORMlite;
 10 
 11 import android.app.Activity;
 12 import android.os.AsyncTask;
 13 import android.os.Bundle;
 14 import android.text.method.ScrollingMovementMethod;
 15 import android.view.View;
 16 import android.view.View.OnClickListener;
 17 import android.widget.Button;
 18 import android.widget.TextView;
 19 import android.widget.Toast;
 20 
 21 public class MainActivity extends Activity {
 22     private Dao<User, Integer> muserDao = null;
 23     private Dao<AClass, Integer> mclassDao = null;
 24     TextView tv;
 25     StringBuffer sb = null;
 26 
 27     @Override
 28     protected void onCreate(Bundle savedInstanceState) {
 29         super.onCreate(savedInstanceState);
 30         setContentView(R.layout.activity_main);
 31 
 32         MyORMlite mMyORMlite = MyORMlite.getInstance(this);
 33         muserDao = mMyORMlite.getuserDao();
 34         mclassDao = mMyORMlite.getclassDao();
 35 
 36         tv = (TextView) findViewById(R.id.tv);
 37         tv.setMovementMethod(ScrollingMovementMethod.getInstance());
 38 
 39         Button btn = (Button) findViewById(R.id.button1);
 40         btn.setOnClickListener(new OnClickListener() {
 41             @Override
 42             public void onClick(View v) {
 43                 MyTask mMyTask = new MyTask();
 44                 mMyTask.execute();
 45             }
 46         });
 47     }
 48 
 49     // 用一个类继承AsyncTask
 50     private class MyTask extends AsyncTask {
 51         // 先执行这个方法 可以处理一些初始化的事件等。
 52         @Override
 53         protected void onPreExecute() {
 54             sb = new StringBuffer();
 55             super.onPreExecute();
 56         }
 57 
 58         // 这个方法可以处理相对耗时较长的任务，这个方法里面不可以执行ui任务。
 59         @Override
 60         protected Object doInBackground(Object... params) {
 61             add();
 62             List<User> list = chaxun();
 63             for (User n : list) {
 64                 sb.append("姓名是：" + n.getName() + ",性别是：" + n.getSex() + ",班级是：" + n.getAclass().getName() + "\n");
 65             }
 66             return sb;
 67         }
 68 
 69         // 可以将上一个方法处理的结果传到这个方法中，并且这个方法里面可以处理ui任务。
 70         @Override
 71         protected void onPostExecute(Object params) {
 72             super.onPostExecute(params);
 73             tv.setText(params.toString());
 74             Toast.makeText(MainActivity.this, "显示成功", 0).show();
 75         }
 76     }
 77 
 78     public List<User> chaxun() {
 79         List<User> list = null;
 80         try {
 81             list = muserDao.queryForAll();
 82 
 83         } catch (SQLException e) {
 84             e.printStackTrace();
 85         }
 86         return list;
 87 
 88     }
 89 
 90     public void add() {
 91 
 92         for (int j = 1; j <= 3; j++) {
 93             AClass classes = null;
 94             classes = new AClass();
 95             classes.setName("大三" + j + "班");
 96             classes.setId(j);
 97             try {
 98                 mclassDao.createIfNotExists(classes);
 99             } catch (SQLException e) {
100                 e.printStackTrace();
101             }
102             for (int i = 10 * (j - 1) + 1; i <= 10 * j; i++) {
103                 User user = new User();
104                 user.setName("张三" + i);
105                 user.setAge(20 + i);
106                 user.setUser_id(i);
107                 user.setSex("男");
108                 user.setAclass(classes);// 挂载到class
109                 try {
110                     muserDao.createIfNotExists(user);
111                 } catch (SQLException e) {
112                     e.printStackTrace();
113                 }
114 
115             }
116         }
117 
118     }
119 }