Android應用開發之ContentProvider

1、PersonProvider

1. package cn.class3g.db;  
2.    
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;  
11.    
12. public class PersonProvider extends ContentProvider {  
13.        private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);  
14.    
15.        private static final int PERSONS = 1;  
16.        private static final int PERSON = 2;  
17.    
18.        private DatabaseHelper dbHelper;  
19.    
20.        static {  
21.               matcher.addURI("cn.class3g.providers.personprovider", "person", PERSONS);  
22.               matcher.addURI("cn.class3g.providers.personprovider", "person/#",  
23.                             PERSON);  
24.        }  
25.    
26.        public boolean onCreate() {  
27.               dbHelper = new DatabaseHelper(this.getContext());  
28.               return true;  
29.        }  
30.    
31.        //  content://cn.itcast.provides.personprovider/person  
32.        public Uri insert(Uri uri, ContentValues values) {  
33.               SQLiteDatabase db = dbHelper.getWritableDatabase();  
34.               long rowId;  
35.    
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.        }  
44.    
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);  
58.                       
59.               default:  
60.                      throw new IllegalArgumentException("Unknown Uri:"+ uri);  
61.               }  
62.        }  
63.    
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.        }  
87.    
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.        }  
108.    
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;  
2.    
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;  
9.    
10. public class AccessContentProviderTest extends AndroidTestCase {  
11.      
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.     }  
21.      
22.     public void testQuery() throws Throwable{  
23.        ContentResolver resolver = this.getContext().getContentResolver();  
24.        Uri uri = Uri.parse("content://cn.class3g.providers.personprovider/person");  
25.         
26.        Cursor cursor = resolver.query(uri, null, null, null, "personid asc");  
27.         
28.        while(cursor.moveToNext()){  
29.            int personid = cursor.getInt(cursor.getColumnIndex("personid"));  
30.            String name = cursor.getString(cursor.getColumnIndex("name"));  
31.             
32.            Log.i("TAG", "personid="+ personid + ",name="+ name);  
33.        }  
34.        cursor.close();  
35.     }  
36.      
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