ListView项目长按的菜单功能总结

ListView上的Item长按弹出菜单或者对话框是常见的功能之一：

其实现如下：

extends ListActivity{

在方法：

@Override

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.localfilebrowser);
registerForContextMenu(this.getListView());

增加方法：

[java] view plain copy print ?

1. @Override
2. public void onCreateContextMenu(ContextMenu menu, View view,
3. ContextMenuInfo menuInfo) {
4. AdapterView.AdapterContextMenuInfo info;
5. try {
6. info = (AdapterView.AdapterContextMenuInfo) menuInfo;
7. } catch (ClassCastException e) {
8. Log.e("test", "bad menuInfo", e);
9. return;
10. }
11. currentPath = new File(paths.get(info.position));
12. showDialog(UPDATE_FILEPATH);
14. }

@Override public void onCreateContextMenu(ContextMenu menu, View view, ContextMenuInfo menuInfo) { AdapterView.AdapterContextMenuInfo info; try { info = (AdapterView.AdapterContextMenuInfo) menuInfo; } catch (ClassCastException e) { Log.e("test", "bad menuInfo", e); return; } currentPath = new File(paths.get(info.position)); showDialog(UPDATE_FILEPATH); }

本文使用了弹出式窗口，如果是菜单的话，需要增加如下代码

[java] view plain copy print ?

1. @Override
2. public boolean onContextItemSelected(MenuItem item) {
3. super.onContextItemSelected(item);
4. AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo) item
5. .getMenuInfo();
6. // Remember current selection
7. IconifiedTextListAdapter adapter = (IconifiedTextListAdapter) getListAdapter();
8. if (adapter == null) {
9. return false;
10. }
11. return true;
12. }

@Override public boolean onContextItemSelected(MenuItem item) { super.onContextItemSelected(item); AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo) item .getMenuInfo(); // Remember current selection IconifiedTextListAdapter adapter = (IconifiedTextListAdapter) getListAdapter(); if (adapter == null) { return false; } return true; }

showDialog(UPDATE_FILEPATH);对应于如下代码

[java] view plain copy print ?

1. @Override
2. protected Dialog onCreateDialog(int id) {
3. switch (id) {
4. case UPDATE_FILEPATH:
5. LayoutInflater inflater = LayoutInflater.from(this);
6. View view = inflater.inflate(R.layout.dialog_change_filepath, null);
7. final TextView oldet = (TextView) view.findViewById(R.id.oldfilepath);
8. final TextView newet = (TextView) view.findViewById(R.id.newfilepath);
9. prefs = PreferenceManager.getDefaultSharedPreferences(this);
10. oldet.setText(oldet.getText()+prefs.getString("CLB_DOWNLOAD_PATH", ""));
11. if(currentPath!=null)
12. newet.setText(newet.getText()+currentPath.getAbsolutePath());
13. return new AlertDialog.Builder(this).setIcon(
14. android.R.drawable.ic_dialog_alert).setTitle(
15. R.string.dialog_filepath).setView(view)
16. .setPositiveButton(android.R.string.ok,
17. new OnClickListener() {
18. public void onClick(DialogInterface dialog,
19. int which) {
20. Editor editor = prefs.edit();
21. editor.putString("CLB_DOWNLOAD_PATH", currentPath.getAbsolutePath());
22. editor.commit();
23. ListOSDir.this.finish();
24. }
25. }).setNegativeButton(android.R.string.cancel,
26. new OnClickListener() {
27. public void onClick(DialogInterface dialog,
28. int which) {
29. // Cancel should not do anything.
30. removeDialog(UPDATE_FILEPATH);
31. }
32. }).create();
33. }
34. return null;
35. }

@Override protected Dialog onCreateDialog(int id) { switch (id) { case UPDATE_FILEPATH: LayoutInflater inflater = LayoutInflater.from(this); View view = inflater.inflate(R.layout.dialog_change_filepath, null); final TextView oldet = (TextView) view.findViewById(R.id.oldfilepath); final TextView newet = (TextView) view.findViewById(R.id.newfilepath); prefs = PreferenceManager.getDefaultSharedPreferences(this); oldet.setText(oldet.getText()+prefs.getString("CLB_DOWNLOAD_PATH", "")); if(currentPath!=null) newet.setText(newet.getText()+currentPath.getAbsolutePath()); return new AlertDialog.Builder(this).setIcon( android.R.drawable.ic_dialog_alert).setTitle( R.string.dialog_filepath).setView(view) .setPositiveButton(android.R.string.ok, new OnClickListener() { public void onClick(DialogInterface dialog, int which) { Editor editor = prefs.edit(); editor.putString("CLB_DOWNLOAD_PATH", currentPath.getAbsolutePath()); editor.commit(); ListOSDir.this.finish(); } }).setNegativeButton(android.R.string.cancel, new OnClickListener() { public void onClick(DialogInterface dialog, int which) { // Cancel should not do anything. removeDialog(UPDATE_FILEPATH); } }).create(); } return null; }

其中：removeDialog(UPDATE_FILEPATH); 是解决

因为create 一个dialog的开销很大，所以android会先查找有没有dialog实例存在，如果有，不create，prepared之后就show，弹出窗口一直都相同的问题

整个程序是选择一个目录来设置下载需要存储的路径的，代码如下：

[java] view plain copy print ?

1. package cn.cnic.cerc.moblie.clbclient.filemanager;
2. import java.io.File;
3. import java.util.ArrayList;
4. import java.util.List;
5. import android.app.AlertDialog;
6. import android.app.Dialog;
7. import android.app.ListActivity;
8. import android.content.DialogInterface;
9. import android.content.SharedPreferences;
10. import android.content.DialogInterface.OnClickListener;
11. import android.content.SharedPreferences.Editor;
12. import android.os.Bundle;
13. import android.os.Environment;
14. import android.preference.PreferenceManager;
15. import android.util.Log;
16. import android.view.ContextMenu;
17. import android.view.LayoutInflater;
18. import android.view.MenuItem;
19. import android.view.View;
20. import android.view.Window;
21. import android.view.ContextMenu.ContextMenuInfo;
22. import android.widget.AdapterView;
23. import android.widget.ArrayAdapter;
24. import android.widget.ListView;
25. import android.widget.TextView;
26. import android.widget.AdapterView.AdapterContextMenuInfo;
27. import cn.cnic.cerc.moblie.clbclient.R;
29. public class ListOSDir extends ListActivity {
30. private static final int UPDATE_FILEPATH = 0;
31. /** Called when the activity is first created. */
32. private List<String> items = null;// 存放名称
33. private List<String> paths = null;// 存放路径
34. private String rootPath = "/";
35. private TextView tv;
36. private SharedPreferences prefs;
37. @Override
38. public void onCreate(Bundle savedInstanceState) {
39. super.onCreate(savedInstanceState);
40. requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
41. setContentView(R.layout.localfilebrowser);
42. registerForContextMenu(this.getListView());
43. tv = (TextView) this.findViewById(R.id.TextView);
44. this.getFileDir(rootPath);// 获取rootPath目录下的文件.
45. prefs = PreferenceManager.getDefaultSharedPreferences(this);
46. if(prefs.getString("CLB_DOWNLOAD_PATH", "").equals(""))
47. {
48. File sdcardDir = Environment.getExternalStorageDirectory();
49. String path = sdcardDir.getParent() + sdcardDir.getName();
50. String fileDirectory = path + java.io.File.separator + "clb";
51. Editor editor = prefs.edit();
52. editor.putString("CLB_DOWNLOAD_PATH", fileDirectory);
53. editor.commit();
54. }
55. }
56. public void getFileDir(String filePath) {
57. try {
58. this.tv.setText("当前路径:" + filePath);// 设置当前所在路径
59. items = new ArrayList<String>();
60. paths = new ArrayList<String>();
61. File f = new File(filePath);
62. File[] files = f.listFiles();// 列出所有文件
63. // 如果不是根目录,则列出返回根目录和上一目录选项
64. if (!filePath.equals(rootPath)) {
65. items.add("返回根目录");
66. paths.add(rootPath);
67. items.add("返回上一层目录");
68. paths.add(f.getParent());
69. }
70. // 将所有文件存入list中
71. if (files != null) {
72. int count = files.length;// 文件个数
73. for (int i = 0; i < count; i++) {
74. File file = files[i];
75. if (file.isDirectory()) {
76. items.add(file.getName());
77. paths.add(file.getPath());
78. }
79. }
80. }
81. ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
82. android.R.layout.simple_list_item_1, items);
83. this.setListAdapter(adapter);
84. } catch (Exception ex) {
85. ex.printStackTrace();
86. }
87. }
88. @Override
89. protected void onListItemClick(ListView l, View v, int position, long id) {
90. super.onListItemClick(l, v, position, id);
91. String path = paths.get(position);
92. File file = new File(path);
93. // 如果是文件夹就继续分解
94. if (file.isDirectory()) {
95. this.getFileDir(path);
96. } else {
97. new AlertDialog.Builder(this).setTitle("提示").setMessage(
98. file.getName() + " 是一个文件！").setPositiveButton("OK",
99. new DialogInterface.OnClickListener() {
100. public void onClick(DialogInterface dialog, int which) {
101. }
102. }).show();
103. }
104. }
105. private File currentPath;
106. @Override
107. public void onCreateContextMenu(ContextMenu menu, View view,
108. ContextMenuInfo menuInfo) {
109. AdapterView.AdapterContextMenuInfo info;
110. try {
111. info = (AdapterView.AdapterContextMenuInfo) menuInfo;
112. } catch (ClassCastException e) {
113. Log.e("test", "bad menuInfo", e);
114. return;
115. }
116. currentPath = new File(paths.get(info.position));
117. showDialog(UPDATE_FILEPATH);
119. }
120. @Override
121. public boolean onContextItemSelected(MenuItem item) {
122. super.onContextItemSelected(item);
123. AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo) item
124. .getMenuInfo();
125. // Remember current selection
126. IconifiedTextListAdapter adapter = (IconifiedTextListAdapter) getListAdapter();
127. if (adapter == null) {
128. return false;
129. }
130. return true;
131. }
133. @Override
134. protected Dialog onCreateDialog(int id) {
135. switch (id) {
136. case UPDATE_FILEPATH:
137. LayoutInflater inflater = LayoutInflater.from(this);
138. View view = inflater.inflate(R.layout.dialog_change_filepath, null);
139. final TextView oldet = (TextView) view.findViewById(R.id.oldfilepath);
140. final TextView newet = (TextView) view.findViewById(R.id.newfilepath);
141. prefs = PreferenceManager.getDefaultSharedPreferences(this);
142. oldet.setText(oldet.getText()+prefs.getString("CLB_DOWNLOAD_PATH", ""));
143. if(currentPath!=null)
144. newet.setText(newet.getText()+currentPath.getAbsolutePath());
145. return new AlertDialog.Builder(this).setIcon(
146. android.R.drawable.ic_dialog_alert).setTitle(
147. R.string.dialog_filepath).setView(view)
148. .setPositiveButton(android.R.string.ok,
149. new OnClickListener() {
150. public void onClick(DialogInterface dialog,
151. int which) {
152. Editor editor = prefs.edit();
153. editor.putString("CLB_DOWNLOAD_PATH", currentPath.getAbsolutePath());
154. editor.commit();
155. ListOSDir.this.finish();
156. }
157. }).setNegativeButton(android.R.string.cancel,
158. new OnClickListener() {
159. public void onClick(DialogInterface dialog,
160. int which) {
161. // Cancel should not do anything.
162. removeDialog(UPDATE_FILEPATH);
163. }
164. }).create();
165. }
166. return null;
167. }
170. }

package cn.cnic.cerc.moblie.clbclient.filemanager; import java.io.File; import java.util.ArrayList; import java.util.List; import android.app.AlertDialog; import android.app.Dialog; import android.app.ListActivity; import android.content.DialogInterface; import android.content.SharedPreferences; import android.content.DialogInterface.OnClickListener; import android.content.SharedPreferences.Editor; import android.os.Bundle; import android.os.Environment; import android.preference.PreferenceManager; import android.util.Log; import android.view.ContextMenu; import android.view.LayoutInflater; import android.view.MenuItem; import android.view.View; import android.view.Window; import android.view.ContextMenu.ContextMenuInfo; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.TextView; import android.widget.AdapterView.AdapterContextMenuInfo; import cn.cnic.cerc.moblie.clbclient.R; public class ListOSDir extends ListActivity { private static final int UPDATE_FILEPATH = 0; /** Called when the activity is first created. */ private List<String> items = null;// 存放名称 private List<String> paths = null;// 存放路径 private String rootPath = "/"; private TextView tv; private SharedPreferences prefs; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); setContentView(R.layout.localfilebrowser); registerForContextMenu(this.getListView()); tv = (TextView) this.findViewById(R.id.TextView); this.getFileDir(rootPath);// 获取rootPath目录下的文件. prefs = PreferenceManager.getDefaultSharedPreferences(this); if(prefs.getString("CLB_DOWNLOAD_PATH", "").equals("")) { File sdcardDir = Environment.getExternalStorageDirectory(); String path = sdcardDir.getParent() + sdcardDir.getName(); String fileDirectory = path + java.io.File.separator + "clb"; Editor editor = prefs.edit(); editor.putString("CLB_DOWNLOAD_PATH", fileDirectory); editor.commit(); } } public void getFileDir(String filePath) { try { this.tv.setText("当前路径:" + filePath);// 设置当前所在路径 items = new ArrayList<String>(); paths = new ArrayList<String>(); File f = new File(filePath); File[] files = f.listFiles();// 列出所有文件 // 如果不是根目录,则列出返回根目录和上一目录选项 if (!filePath.equals(rootPath)) { items.add("返回根目录"); paths.add(rootPath); items.add("返回上一层目录"); paths.add(f.getParent()); } // 将所有文件存入list中 if (files != null) { int count = files.length;// 文件个数 for (int i = 0; i < count; i++) { File file = files[i]; if (file.isDirectory()) { items.add(file.getName()); paths.add(file.getPath()); } } } ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, items); this.setListAdapter(adapter); } catch (Exception ex) { ex.printStackTrace(); } } @Override protected void onListItemClick(ListView l, View v, int position, long id) { super.onListItemClick(l, v, position, id); String path = paths.get(position); File file = new File(path); // 如果是文件夹就继续分解 if (file.isDirectory()) { this.getFileDir(path); } else { new AlertDialog.Builder(this).setTitle("提示").setMessage( file.getName() + " 是一个文件！").setPositiveButton("OK", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { } }).show(); } } private File currentPath; @Override public void onCreateContextMenu(ContextMenu menu, View view, ContextMenuInfo menuInfo) { AdapterView.AdapterContextMenuInfo info; try { info = (AdapterView.AdapterContextMenuInfo) menuInfo; } catch (ClassCastException e) { Log.e("test", "bad menuInfo", e); return; } currentPath = new File(paths.get(info.position)); showDialog(UPDATE_FILEPATH); } @Override public boolean onContextItemSelected(MenuItem item) { super.onContextItemSelected(item); AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo) item .getMenuInfo(); // Remember current selection IconifiedTextListAdapter adapter = (IconifiedTextListAdapter) getListAdapter(); if (adapter == null) { return false; } return true; } @Override protected Dialog onCreateDialog(int id) { switch (id) { case UPDATE_FILEPATH: LayoutInflater inflater = LayoutInflater.from(this); View view = inflater.inflate(R.layout.dialog_change_filepath, null); final TextView oldet = (TextView) view.findViewById(R.id.oldfilepath); final TextView newet = (TextView) view.findViewById(R.id.newfilepath); prefs = PreferenceManager.getDefaultSharedPreferences(this); oldet.setText(oldet.getText()+prefs.getString("CLB_DOWNLOAD_PATH", "")); if(currentPath!=null) newet.setText(newet.getText()+currentPath.getAbsolutePath()); return new AlertDialog.Builder(this).setIcon( android.R.drawable.ic_dialog_alert).setTitle( R.string.dialog_filepath).setView(view) .setPositiveButton(android.R.string.ok, new OnClickListener() { public void onClick(DialogInterface dialog, int which) { Editor editor = prefs.edit(); editor.putString("CLB_DOWNLOAD_PATH", currentPath.getAbsolutePath()); editor.commit(); ListOSDir.this.finish(); } }).setNegativeButton(android.R.string.cancel, new OnClickListener() { public void onClick(DialogInterface dialog, int which) { // Cancel should not do anything. removeDialog(UPDATE_FILEPATH); } }).create(); } return null; } }

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