Android 对listview数据的增删改查

图-1 android 实现对listview数据的增删改查主要界面

本例只有一个UpdateListViewActivity类，相关的操作以及功能均在一个界面完成。对listview 数据的增删改查，实质就是对填充的数组（填充的数据）进行重新修改后，再次调用notifyDataSetChanged（）方法进行更新。尽管如此，对数据使用起来还是比较生疏，下面的例子能加强对listview数据更新的理解。

UpdateListViewActivity.java类是程序的唯一的一个类，实现了对listview增删改查的操作，代码比较多，但理解并不比较复杂。

1.UpdateListViewActivity.java

1.package com.updatelistview.main;

2.

3.import java.util.ArrayList;

4.import java.util.HashMap;

5.

6.import android.app.Activity;

7.import android.app.AlertDialog;

8.import android.content.Context;

9.import android.content.DialogInterface;

10.import android.os.Bundle;

11.import https://www.360docs.net/doc/1d3031453.html,youtInflater;

12.import android.view.View;

13.import android.view.View.OnClickListener;

14.import android.widget.Button;

15.import android.widget.EditText;

16.import android.widget.LinearLayout;

17.import android.widget.ListView;

18.import android.widget.SimpleAdapter;

19.import android.widget.Toast;

20.

21.public class UpdateListViewActivity extends Activity {

22.// 控件

23.private Button addBtn;

24.private Button deleteBtn;

25.private Button editBtn;

26.private Button queryBtn;

27.private ListView listview;

28.// 数组

29.private SimpleAdapter listItemAdapter;

30.private ArrayList> listItem = null;

31.

32./** Called when the activity is first created. */

33.@Override

34.public void onCreate(Bundle savedInstanceState) {

35.super.onCreate(savedInstanceState);

36. setContentView(https://www.360docs.net/doc/1d3031453.html,yout.main);

37.

38.// 获取控件

39. addBtn = (Button) findViewById(R.id.add_id);

40. deleteBtn = (Button) findViewById(R.id.delete_id);

41. editBtn = (Button) findViewById(R.id.edit_id);

42. queryBtn = (Button) findViewById(R.id.query_id);

43. listview = (ListView) findViewById(R.id.show_result);

44.

45.// 初始化数据

46. init();

47.

48.// 设置控件事件监听

49. addBtn.setOnClickListener(addClick);

50. deleteBtn.setOnClickListener(deleteClick);

51. editBtn.setOnClickListener(editClick);

52. queryBtn.setOnClickListener(queryClick);

53.

54. }

55.

56.// 添加事件响应

57. OnClickListener addClick = new OnClickListener() {

58.

59.@Override

60.public void onClick(View v) {

61.// TODO Auto-generated method stub

62.

63.// 加载输入框的布局文件

64. LayoutInflater inflater = (LayoutInflater) UpdateListViewActivity.this

65. .getSystemService(https://www.360docs.net/doc/1d3031453.html,YOUT_INFLATER_SERVICE);

66.final LinearLayout layout = (LinearLayout) inflater.inflate(

67. https://www.360docs.net/doc/1d3031453.html,yout.input_add, null);

68.

69.// 弹出的对话框

70.

71.new AlertDialog.Builder(UpdateListViewActivity.this)

72./* 弹出窗口的最上头文字 */

73. .setTitle("添加一条数据")

74./* 设置弹出窗口的图式 */

75. .setIcon(android.R.drawable.ic_dialog_info)

76./* 设置弹出窗口的信息 */

77. .setMessage("请输入添加的内容")

78. .setView(layout)

79. .setPositiveButton("确定",

80.new DialogInterface.OnClickListener() {

81.public void onClick(

82. DialogInterface dialoginterface, int i) {

83.

84. EditText inputStringr = (EditText) layout

85. .findViewById(R.id.input_add_string);

86.

87. String str = inputStringr.getText()

88. .toString();

89.

90.if (str == null || str.equals("")) {

91.

92. Toast.makeText(getApplicationContext(),

93."添加的内容不能为空

", Toast.LENGTH_SHORT)

94. .show();

95. } else {

96. HashMap map = new HashMap<

STRING, Object>();

97. map.put("viewspot", str);

98. map.put("add", R.drawable.right);

99. listItem.add(0, map);

100.// 如果在前面添加一条数据添加

101.// listItem.add(map);

102. listItemAdapter.notifyDataSetChanged();

103. Toast.makeText(

104. UpdateListViewActivity.this,

105."添加的一条数据为:" + str + "",

106. Toast.LENGTH_SHORT).show();

107.

108. }

109.

110. }

111. })

112. .setNegativeButton("取消",

113.new DialogInterface.OnClickListener() { /* 设置跳出窗口的返回事件 */

114.public void onClick(

115. DialogInterface dialoginterface, int i) {

116. Toast.makeText(UpdateListViewActivity.this, 117."取消了删除数据", Toast.LENGTH_SHORT) 118. .show();

119.

120. }

121. }).show();

122.

123. }

124. };

125.

126.// 删除事件响应

127. OnClickListener deleteClick = new OnClickListener() {

128.

129.@Override

130.public void onClick(View v) {

131.// TODO Auto-generated method stub

132.

133./**

134. * listItem.clear();清空所有数据

135. *

136. * */

137.

138./*

139. * listItem.clear();

140. * listItemAdapter.notifyDataSetChanged();

141. */

142.

143.// 加载输入框的布局文件

144. LayoutInflater inflater = (LayoutInflater) UpdateListViewActivity.this 145. .getSystemService(https://www.360docs.net/doc/1d3031453.html,YOUT_INFLATER_SERVICE); 146.final LinearLayout layout = (LinearLayout) inflater.inflate(

147. https://www.360docs.net/doc/1d3031453.html,yout.input_delete, null);

148.

149.// 弹出的对话框

150.

151.new AlertDialog.Builder(UpdateListViewActivity.this)

152./* 弹出窗口的最上头文字 */

153. .setTitle("删除一条数据")

154./* 设置弹出窗口的图式 */

155. .setIcon(android.R.drawable.ic_dialog_info)

156./* 设置弹出窗口的信息 */

157. .setMessage("请输入删除的索引")

158. .setView(layout)

159. .setPositiveButton("确定",

160.new DialogInterface.OnClickListener() {

161.public void onClick(

162. DialogInterface dialoginterface, int i) {

163.

164. EditText inputNumber = (EditText) layout

165. .findViewById(R.id.input_delete_number); 166.

167. String str = inputNumber.getText()

168. .toString();

169.

170.if (str == null || str.equals("")) {

171.

172. Toast.makeText(getApplicationContext(), 173."请输入一个数字", Toast.LENGTH_SHORT) 174. .show();

175. } else {

176.int number = Integer.valueOf(str);

177.

178.int size = listItem.size();

179.

180.// 判断数字是否超出数组索引范围

181.if (number >= size) {

182. Toast.makeText(

183. getApplicationContext(),

184."没有找到删除的数据索引",

185. Toast.LENGTH_SHORT).show();

186.

187. } else {

188.

189. String value = listItem.get(number)

190. .toString();

191. listItem.remove(number);

192. listItemAdapter

193. .notifyDataSetChanged();

194. Toast.makeText(

195. UpdateListViewActivity.this,

196."删除的数据为:" + value + "",

197. Toast.LENGTH_SHORT).show();

198.

199. }

200. }

201.

202. }

203. })

204. .setNegativeButton("取消",

205.new DialogInterface.OnClickListener() { /* 设置跳出窗口的返回事件 */

206.public void onClick(

207. DialogInterface dialoginterface, int i) {

208. Toast.makeText(UpdateListViewActivity.this, 209."取消了删除数据", Toast.LENGTH_SHORT) 210. .show();

211.

212. }

213. }).show();

214.

215. }

216. };

217.// 修改事件响应

218. OnClickListener editClick = new OnClickListener() {

219.

220.@Override

221.public void onClick(View v) {

222.// TODO Auto-generated method stub

223.// 加载输入框的布局文件

224. LayoutInflater inflater = (LayoutInflater) UpdateListViewActivity.this 225. .getSystemService(https://www.360docs.net/doc/1d3031453.html,YOUT_INFLATER_SERVICE); 226.final LinearLayout layout = (LinearLayout) inflater.inflate(

227. https://www.360docs.net/doc/1d3031453.html,yout.input_edit, null);

228.

229.// 弹出的对话框

230.

231.new AlertDialog.Builder(UpdateListViewActivity.this)

232./* 弹出窗口的最上头文字 */

233. .setTitle("修改一条数据")

234./* 设置弹出窗口的图式 */

235. .setIcon(android.R.drawable.ic_dialog_info)

236./* 设置弹出窗口的信息 */

237. .setMessage("请输入修改的索引及内容")

238. .setView(layout)

239. .setPositiveButton("确定",

240.new DialogInterface.OnClickListener() {

241.public void onClick(

242. DialogInterface dialoginterface, int i) {

243.

244. EditText inputEditNumber = (EditText) layout 245. .findViewById(R.id.input_edit_number); 246.

247. String numberStr = inputEditNumber

248. .getText().toString();

249.

250. EditText inputEditString = (EditText) layout 251. .findViewById(R.id.input_edit_string); 252.

253. String editStr = inputEditString.getText()

254. .toString();

255.

256.if (numberStr == null

257. || numberStr.equals("")) {

258.

259. Toast.makeText(getApplicationContext(), 260."请输入要修改的索引

", Toast.LENGTH_SHORT)

261. .show();

262. } else {

263.int number = Integer.valueOf(numberStr); 264.

265.int size = listItem.size();

266.

267.// 判断数字是否超出数组索引范围

268.if (number >= size) {

269. Toast.makeText(

270. getApplicationContext(),

271."没有找到修改的数据索引",

272. Toast.LENGTH_SHORT).show();

273.

274. } else {

275.

276. HashMap map = new HashM ap();

277. map.put("viewspot", editStr);

278. map.put("add", R.drawable.right);

279.

280. listItem.set(number, map);

281. listItemAdapter

282. .notifyDataSetChanged();

283.

284. Toast.makeText(

285. UpdateListViewActivity.this,

286."数据修改为:" + editStr + "",

287. Toast.LENGTH_SHORT).show();

288.

289. }

290. }

291.

292. }

293. })

294. .setNegativeButton("取消",

295.new DialogInterface.OnClickListener() { /* 设置跳出窗口的返回事件 */

296.public void onClick(

297. DialogInterface dialoginterface, int i) {

298. Toast.makeText(UpdateListViewActivity.this, 299."取消了修改数据", Toast.LENGTH_SHORT) 300. .show();

301.

302. }

303. }).show();

304.

305. }

306. };

307.

308.// 查询事件响应

309. OnClickListener queryClick = new OnClickListener() {

310.

311.@Override

312.public void onClick(View v) {

313.// TODO Auto-generated method stub

314.// 查询数据

315. listItemAdapter.notifyDataSetChanged();

316. }

317. };

318.

319.// 初始化数据

320.private void init() {

321.

322. listItem = new ArrayList>();

323.for (int i = 0; i < 12; i++) {

324. HashMap map = new HashMap() ;

325. map.put("viewspot", "北京故宫，颐和园" + i);

326. map.put("add", R.drawable.right);

327. listItem.add(map);

328. }

329. listItemAdapter = new SimpleAdapter(getApplicationContext(), listItem,// 数据源

330. https://www.360docs.net/doc/1d3031453.html,yout.items, new String[] { "viewspot", "add" }, new int[] { 331. R.id.viewspot, R.id.add });

332. listview.setAdapter(listItemAdapter);

333.

334. } 335. 336.}