Listview中取数据

1. package com.hgq.hepler;
   
2. 
   
3. import android.content.ContentValues;
   
4. import android.content.Context;
   
5. import android.database.Cursor;
   
6. import android.database.sqlite.SQLiteDatabase;
   
7. import android.database.sqlite.SQLiteOpenHelper;
   
8. 
   
9. public class MyDatabaseHepler extends SQLiteOpenHelper
   
10. {
    
11. 
    
12. // 数据库名称
    
13. private static final String DB_NAME = "notepad.db";
    
14. // 数据表名称
    
15. private static final String TABLE_NAME = "data";
    
16. // 数据库版本
    
17. private static final int DB_VERSION = 1;
    
18. // 创建数据表SQL语句
    
19. private static final String CREATE_TABLE = 
    
20. "CREATE TABLE " + TABLE_NAME
    
21. + "(" 
    
22. + "_id INTEGER PRIMARY KEY ,"
    
23. + "title VARCHAR(50) NOT NULL ," 
    
24. + "body" 
    
25. + ")";
    
26. // 删除数据表SQL语句
    
27. private static final String DROP_TABLE = "DROP IF TABLE EXISTS "
    
28. + TABLE_NAME;
    
29. // 定义SQLiteDatabase
    
30. private SQLiteDatabase db;
    
31. 
    
32. public MyDatabaseHepler(Context context)
    
33. {
    
34. super(context, DB_NAME, null, DB_VERSION);
    
35. System.out.println("--------------------数据库创建成功!!");
    
36. }
    
37. 
    
38. @Override
    
39. public void onCreate(SQLiteDatabase db)
    
40. {
    
41. // 创建数据表
    
42. db.execSQL(CREATE_TABLE);
    
43. System.out.println("------------------------数据表创建成功!!");
    
44. }
    
45. 
    
46. @Override
    
47. public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    
48. {
    
49. db.execSQL(DROP_TABLE);
    
50. System.out.println("-------------------------数据表更新成功!!");
    
51. onCreate(db);
    
52. }
    
53. 
    
54. /**
    
55. * 插入数据
    
56. * 
    
57. * @param values
    
58. */
    
59. public void insert(ContentValues values)
    
60. {
    
61. SQLiteDatabase db = getWritableDatabase();
    
62. 
    
63. db.insert(TABLE_NAME, null, values);
    
64. 
    
65. db.close();
    
66. }
    
67. 
    
68. /**
    
69. * 查询数据
    
70. */
    
71. public Cursor query()
    
72. {
    
73. SQLiteDatabase db = getWritableDatabase();
    
74. 
    
75. Cursor cursor = db
    
76. .query(TABLE_NAME, null, null, null, null, null, null);
    
77. 
    
78. return cursor;
    
79. }
    
80. 
    
81. /**
    
82. * 删除数据
    
83. */
    
84. public void delete(long id)
    
85. {
    
86. if (db == null)
    
87. {
    
88. db = getWritableDatabase();
    
89. }
    
90. db.delete(TABLE_NAME, "_id=?",new String[]{String.valueOf(id)});
    
91. }
    
92. 
    
93. /**
    
94. * 更新数据
    
95. */
    
96. public void update(long id){
    
97. db=getWritableDatabase();
    
98. ContentValues values=new ContentValues();
    
99. 
    
100. // db.update(TABLE_NAME, values, whereClause, whereArgs)
     
101. }
     
102. }
     
103. 
     

复制代码

这是MainActivity类

1. package com.hgq.demo;
   
2. 
   
3. import java.util.HashMap;
   
4. import java.util.Map;
   
5. 
   
6. import android.annotation.SuppressLint;
   
7. import android.app.AlertDialog;
   
8. import android.app.ListActivity;
   
9. import android.content.DialogInterface;
   
10. import android.content.DialogInterface.OnClickListener;
    
11. import android.content.Intent;
    
12. import android.database.Cursor;
    
13. import android.database.sqlite.SQLiteDatabase;
    
14. import android.os.Bundle;
    
15. import android.view.ContextMenu;
    
16. import android.view.ContextMenu.ContextMenuInfo;
    
17. import android.view.Menu;
    
18. import android.view.MenuItem;
    
19. import android.view.View;
    
20. import android.widget.AdapterView;
    
21. import android.widget.AdapterView.AdapterContextMenuInfo;
    
22. import android.widget.AdapterView.OnItemClickListener;
    
23. import android.widget.ListView;
    
24. import android.widget.SimpleCursorAdapter;
    
25. 
    
26. import com.hgq.hepler.MyDatabaseHepler;
    
27. 
    
28. public class MainActivity extends ListActivity
    
29. {
    
30. // 选项菜单
    
31. private static final int DB_INSERT = Menu.FIRST + 1;
    
32. 
    
33. // 上下文菜单
    
34. private static final int DB_DELETE = Menu.FIRST + 2;
    
35. 
    
36. // 定义帮助类
    
37. private MyDatabaseHepler dbHepler;
    
38. SQLiteDatabase db;
    
39. 
    
40. @Override
    
41. public void onCreate(Bundle savedInstanceState)
    
42. {
    
43. super.onCreate(savedInstanceState);
    
44. init();
    
45. }
    
46. 
    
47. public void init()
    
48. {
    
49. // 注册上下文菜单
    
50. registerForContextMenu(getListView());
    
51. 
    
52. dbHepler = new MyDatabaseHepler(getApplicationContext());
    
53. 
    
54. Cursor cursor = dbHepler.query();
    
55. 
    
56. // 游标适配器
    
57. SimpleCursorAdapter adapter = new SimpleCursorAdapter(
    
58. MainActivity.this
    
59. , R.layout.line
    
60. , cursor
    
61. , new String[]{ "_id", "title", "body" }
    
62. , new int[]{ R.id.id, R.id.title, R.id.body }
    
63. );
    
64. 
    
65. ListView list = getListView();
    
66. list.setAdapter(adapter);
    
67. }
    
68. 
    
69. /**
    
70. * 删除
    
71. */
    
72. public void delete(long id)
    
73. {
    
74. final long temp=id;
    
75. AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
    
76. builder.setTitle("删除记录")
    
77. .setMessage("确定删除吗？")
    
78. .setIcon(R.drawable.icon_del)
    
79. .setPositiveButton("确定", new DialogInterface.OnClickListener()
    
80. {
    
81. 
    
82. @Override
    
83. public void onClick(DialogInterface dialog, int which)
    
84. {
    
85. dbHepler.delete(temp);
    
86. init();
    
87. }
    
88. }).setNegativeButton("取消", null).create();
    
89. builder.show();
    
90. }
    
91. 
    
92. /**
    
93. * 更新
    
94. */
    
95. public void update(){
    
96. Intent intent=getIntent();
    
97. String title=intent.getStringExtra("title");
    
98. String body=intent.getStringExtra("body");
    
99. 
    
100. System.out.println("title"+title+",body"+body);
     
101. }
     
102. 
     
103. /**
     
104. * 选项菜单
     
105. */
     
106. @Override
     
107. public boolean onCreateOptionsMenu(Menu menu)
     
108. {
     
109. menu.add(0, DB_INSERT, 0, "新建记事本").setIcon(R.drawable.icon_add);
     
110. return super.onCreateOptionsMenu(menu);
     
111. }
     
112. 
     
113. /**
     
114. * 选项菜单监听
     
115. */
     
116. @Override
     
117. public boolean onOptionsItemSelected(MenuItem item)
     
118. {
     
119. switch (item.getItemId())
     
120. {
     
121. case DB_INSERT:
     
122. Intent intent = new Intent(MainActivity.this, AddNotepad.class);
     
123. startActivityForResult(intent, 0);
     
124. break;
     
125. }
     
126. 
     
127. return super.onOptionsItemSelected(item);
     
128. }
     
129. 
     
130. /**
     
131. * 上下文菜单
     
132. */
     
133. @Override
     
134. public void onCreateContextMenu(ContextMenu menu, View v,
     
135. ContextMenuInfo menuInfo)
     
136. {
     
137. menu.setHeaderTitle("信息操作");
     
138. menu.add(0, DB_DELETE, 0, "删除");
     
139. 
     
140. super.onCreateContextMenu(menu, v, menuInfo);
     
141. }
     
142. 
     
143. /**
     
144. * 上下文菜单监听
     
145. */
     
146. @Override
     
147. public boolean onContextItemSelected(MenuItem item)
     
148. {
     
149. switch (item.getItemId())
     
150. {
     
151. case DB_DELETE:
     
152. AdapterContextMenuInfo info = (AdapterContextMenuInfo) item
     
153. .getMenuInfo();
     
154. delete(info.id);
     
155. break;
     
156. }
     
157. 
     
158. return super.onContextItemSelected(item);
     
159. }
     
160. 
     
161. }

复制代码

这是AddActivity类

1. package com.hgq.demo;
   
2. 
   
3. import android.app.Activity;
   
4. import android.content.ContentValues;
   
5. import android.content.Intent;
   
6. import android.database.sqlite.SQLiteDatabase;
   
7. import android.os.Bundle;
   
8. import android.view.View;
   
9. import android.view.View.OnClickListener;
   
10. import android.widget.Button;
    
11. import android.widget.EditText;
    
12. import android.widget.Toast;
    
13. 
    
14. import com.hgq.hepler.MyDatabaseHepler;
    
15. 
    
16. public class AddNotepad extends Activity
    
17. {
    
18. // 定于组件
    
19. private EditText editTitle, editBody;
    
20. private Button butAdd;
    
21. 
    
22. // 定义帮助类
    
23. private MyDatabaseHepler dbHepler;
    
24. // 定义数据类
    
25. private SQLiteDatabase db;
    
26. // 数据表名称
    
27. private static final String TABLE_NAME = "data";
    
28. 
    
29. private String title;
    
30. private String body;
    
31. 
    
32. @Override
    
33. protected void onCreate(Bundle savedInstanceState)
    
34. {
    
35. super.onCreate(savedInstanceState);
    
36. super.setContentView(R.layout.add);
    
37. 
    
38. init();
    
39. }
    
40. 
    
41. public void init()
    
42. {
    
43. // 实例化帮助类
    
44. dbHepler = new MyDatabaseHepler(getApplicationContext());
    
45. dbHepler.getWritableDatabase();
    
46. // 取出组件
    
47. editTitle = (EditText) findViewById(R.id.editTitle);
    
48. editBody = (EditText) findViewById(R.id.editBody);
    
49. butAdd = (Button) findViewById(R.id.butAdd);
    
50. 
    
51. // 设置添加按钮监听
    
52. butAdd.setOnClickListener(new OnClickListener()
    
53. {
    
54. 
    
55. @Override
    
56. public void onClick(View v)
    
57. {
    
58. title = editTitle.getText().toString();
    
59. body = editBody.getText().toString();
    
60. 
    
61. ContentValues cValues = new ContentValues();
    
62. cValues.put("title", title);
    
63. cValues.put("body", body);
    
64. 
    
65. dbHepler.insert(cValues);
    
66. 
    
67. // 提示保存成功
    
68. Toast.makeText(AddNotepad.this, "保存成功", 8000).show();
    
69. 
    
70. // 定义 Intent
    
71. Intent intent = new Intent(AddNotepad.this, MainActivity.class);
    
72. intent.putExtra("title", title);
    
73. intent.putExtra("body", body);
    
74. 
    
75. // 启动Activity
    
76. startActivityForResult(intent, 0);
    
77. }
    
78. });
    
79. 
    
80. }
    
81. 
    
82. public void update(long id){
    
83. 
    
84. }
    
85. 
    
86. }