Android應用開發之ContentProvider

1、PersonProvider

1. package cn.class3g.db;
3. import cn.class3g.service.DatabaseHelper;
4. import Android.content.ContentProvider;
5. import android.content.ContentUris;
6. import android.content.ContentValues;
7. import android.content.UriMatcher;
8. import android.database.Cursor;
9. import android.database.sqlite.SQLiteDatabase;
10. import android.net.Uri;
12. public class PersonProvider extends ContentProvider {
13. private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
15. private static final int PERSONS = 1;
16. private static final int PERSON = 2;
18. private DatabaseHelper dbHelper;
20. static {
21. matcher.addURI("cn.class3g.providers.personprovider", "person", PERSONS);
22. matcher.addURI("cn.class3g.providers.personprovider", "person/#",
23. PERSON);
24. }
26. public boolean onCreate() {
27. dbHelper = new DatabaseHelper(this.getContext());
28. return true;
29. }
31. // content://cn.itcast.provides.personprovider/person
32. public Uri insert(Uri uri, ContentValues values) {
33. SQLiteDatabase db = dbHelper.getWritableDatabase();
34. long rowId;
36. switch (matcher.match(uri)) {
37. case PERSONS: //向表中添加新紀錄並返回其行號
38. rowId = db.insert("person", "personid", values);
39. return ContentUris.withAppendedId(uri, rowId);
40. default:
41. throw new IllegalArgumentException("Unknow Uri:" + uri);
42. }
43. }
45. public Cursor query(Uri uri, String[] projection, String selection,
46. String[] selectionArgs, String sortOrder) {
47. SQLiteDatabase db = dbHelper.getReadableDatabase();
48. switch (matcher.match(uri)) {
49. case PERSONS:
50. return db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
51. case PERSON:
52. long personid = ContentUris.parseId(uri);
53. String where = "personid="+ personid;
54. if(selection!=null && !"".equals(selection)){
55. wherewhere = where + " and "+ selection;
56. }
57. return db.query("person", projection, where, selectionArgs, null, null, sortOrder);
59. default:
60. throw new IllegalArgumentException("Unknown Uri:"+ uri);
61. }
62. }
64. // content://cn.itcast.provides.personprovider/person 更新表中的所有記錄
65. // content://cn.itcast.provides.personprovider/person/10 更新表中指定id的記錄
66. public int update(Uri uri, ContentValues values, String selection,
67. String[] selectionArgs) {
68. SQLiteDatabase db = dbHelper.getWritableDatabase();
69. int num;
70. switch(matcher.match(uri)){
71. case PERSONS: //更新指定記錄
72. num = db.update("person", values, selection, selectionArgs);
73. break;
74. case PERSON:
75. long personid = ContentUris.parseId(uri);
76. String where = "personid=" + personid;
77. if(selection != null){
78. where += " and " + selection;
79. }
80. num = db.update("person", values, where, selectionArgs);
81. break;
82. default:
83. throw new IllegalArgumentException("Unknow Uri"+uri);
84. }
85. return num;
86. }
88. public int delete(Uri uri, String selection, String[] selectionArgs) {
89. SQLiteDatabase db = dbHelper.getWritableDatabase();
90. int num = 0;
91. switch (matcher.match(uri)) {
92. case PERSONS:
93. num = db.delete("person", selection, selectionArgs);
94. break;
95. case PERSON:
96. long personid = ContentUris.parseId(uri);
97. String where = "personid="+ personid;
98. if(selection!=null && !"".equals(selection)){
99. wherewhere = where + " and "+ selection;
100. }
101. num = db.delete("person", where, selectionArgs);
102. break;
103. default:
104. throw new IllegalArgumentException("Unknown Uri:"+ uri);
105. }
106. return num;
107. }
109. public String getType(Uri uri) {
110. switch (matcher.match(uri)) {
111. case PERSONS:
112. return "vnd.android.cursor.dir/person";
113. case PERSON:
114. return "vnd.android.cursor.item/person";
115. default:
116. throw new IllegalArgumentException("Unknown Uri:"+ uri);
117. }
118. }
119. }

2、配置

1. <provider
2. android:authorities="cn.class3g.providers.personprovider"
3. android:name="PersonProvider" >
4. </provider>

3、建立測試工程編寫測試代碼

1. package cn.class3g.visitor;
3. import android.content.ContentResolver;
4. import android.content.ContentValues;
5. import android.database.Cursor;
6. import android.net.Uri;
7. import android.test.AndroidTestCase;
8. import android.util.Log;
10. public class AccessContentProviderTest extends AndroidTestCase {
12. public void testSave() throws Throwable{
13. ContentResolver resolver = this.getContext().getContentResolver();
14. Uri insertUri = Uri.parse("content://cn.class3g.providers.personprovider/person");
15. ContentValues values = new ContentValues();
16. values.put("name", "laozhang");
17. values.put("age", "50");
18. Uri uri = resolver.insert(insertUri, values);
19. Log.i("TAG", uri.toString());
20. }
22. public void testQuery() throws Throwable{
23. ContentResolver resolver = this.getContext().getContentResolver();
24. Uri uri = Uri.parse("content://cn.class3g.providers.personprovider/person");
26. Cursor cursor = resolver.query(uri, null, null, null, "personid asc");
28. while(cursor.moveToNext()){
29. int personid = cursor.getInt(cursor.getColumnIndex("personid"));
30. String name = cursor.getString(cursor.getColumnIndex("name"));
32. Log.i("TAG", "personid="+ personid + ",name="+ name);
33. }
34. cursor.close();
35. }
37. public void testUpdate() throws Throwable{
38. ContentResolver contentResolver = this.getContext().getContentResolver();
39. Uri updateUri = Uri.parse("content://cn.class3g.providers.personprovider/person/5");
40. ContentValues values = new ContentValues();
41. values.put("name", "蔣介石");
42. contentResolver.update(updateUri, values, null, null);
43. }
44. public void testDelete() throws Throwable{
45. ContentResolver contentResolver = this.getContext().getContentResolver();
46. Uri uri = Uri.parse("content://cn.class3g.providers.personprovider/person/5");
47. contentResolver.delete(uri, null, null);
48. }
49. }

4、測試（注意需要先將provider擁有者工程部署到設備上）

5、ContentProvider的監聽器