内容提供者

1  <provider android:name="com.example.mydbtest.PersonDBProvider"//全路径
2             android:authorities="com.example.mydbtest.personprovider"//表明相当于主机名的东西
3             ></provider>

  1 package com.example.mydbtest;
  2 
  3 import com.example.mydbtest.dao.PersonDao;
  4 
  5 import android.content.ContentProvider;
  6 import android.content.ContentUris;
  7 import android.content.ContentValues;
  8 import android.content.UriMatcher;
  9 import android.database.Cursor;
 10 import android.database.sqlite.SQLiteDatabase;
 11 import android.net.Uri;
 12 
 13 public class PersonDBProvider extends ContentProvider {
 14 
 15     //定义uri的匹配器,如果路径不满足，则返回-1
 16     private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
 17     private PersonSQLiteOpenHelper helper;
 18     //content:com.example.mydbtest.personprovider/insert  添加的操作
 19     //content:com.example.mydbtest.personprovider/update  修改的操作
 20     //content:com.example.mydbtest.personprovider/delete  删除的操作
 21     //content:com.example.mydbtest.personprovider/query   查询的操作
 22     
 23     private static final int INSERT =1;
 24     private static final int DELETE =2;
 25     private static final int UPDATE =3;
 26     private static final int QUERY =4;
 27     private static final int QUERYONE = 5;
 28     static{
 29         //添加匹配规则,第一个参数相当于主机名；第二个参数是路径；第三个参数是匹配成功后的返回值；若匹配不成功，则返回-1
 30         
 31         matcher.addURI("com.example.mydbtest.personprovider", "insert", INSERT);
 32         matcher.addURI("com.example.mydbtest.personprovider", "delete", DELETE);
 33         matcher.addURI("com.example.mydbtest.personprovider", "update", UPDATE);
 34         matcher.addURI("com.example.mydbtest.personprovider", "query", QUERY);
 35         
 36         matcher.addURI("com.example.mydbtest.personprovider", "query/#", QUERYONE);//#代表具体id,可以通过long id = ContentUris.parseId(uri);获取
 37     }
 38     @Override
 39         //适合初始化
 40     public boolean onCreate() {
 41         // TODO Auto-generated method stub
 42         helper = new PersonSQLiteOpenHelper(getContext());
 43         return false;
 44     }
 45 
 46     @Override
 47     public Cursor query(Uri uri, String[] projection, String selection,
 48             String[] selectionArgs, String sortOrder) {
 49         // TODO Auto-generated method stub
 50         if(matcher.match(uri) == QUERY){
 51             SQLiteDatabase db = helper.getReadableDatabase();
 52             Cursor cursor = db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
 53             return cursor;//注意这里请不要关闭数据库，否则cursor拿不到数据
 54         }else{
 55             throw new IllegalArgumentException("路径不匹配，不能执行查询操作");
 56         }
 57         
 58     }
 59 
 60     @Override
 61     public String getType(Uri uri) {
 62         // TODO Auto-generated method stub
 63         return null;
 64     }
 65 
 66     @Override
 67     public Uri insert(Uri uri, ContentValues values) {
 68         // TODO Auto-generated method stub
 69         if(matcher.match(uri) == INSERT){
 70             SQLiteDatabase db = helper.getReadableDatabase();
 71             db.insert("person", null, values);
 72             getContext().getContentResolver().notifyChange(PersonDao.messageuri, null);
 73         }else{
 74             throw new IllegalArgumentException("路径不匹配，不能执行添加操作");
 75         }
 76         return null;
 77     }
 78 
 79     @Override
 80     public int delete(Uri uri, String selection, String[] selectionArgs) {
 81         // TODO Auto-generated method stub
 82         if(matcher.match(uri) == DELETE){
 83             SQLiteDatabase db = helper.getReadableDatabase();
 84             db.delete("person", selection, selectionArgs);
 85             getContext().getContentResolver().notifyChange(PersonDao.messageuri, null);
 86         }else{
 87             throw new IllegalArgumentException("路径不匹配，不能执行插入操作");
 88         }
 89         return 0;
 90     }
 91 
 92     @Override
 93     public int update(Uri uri, ContentValues values, String selection,
 94             String[] selectionArgs) {
 95         // TODO Auto-generated method stub
 96         if(matcher.match(uri) == UPDATE){
 97             SQLiteDatabase db = helper.getReadableDatabase();
 98             db.update("person", values, selection, selectionArgs);
 99             getContext().getContentResolver().notifyChange(PersonDao.messageuri, null);
100         }else{
101             throw new IllegalArgumentException("路径不匹配，不能执行插入操作");
102         }
103         return 0;
104     }
105 
106 }

 1 package com.example.otherlistview;
 2 
 3 import android.net.Uri;
 4 import android.os.Bundle;
 5 import android.app.Activity;
 6 import android.content.ContentResolver;
 7 import android.content.ContentValues;
 8 import android.database.Cursor;
 9 import android.view.Menu;
10 import android.view.View;
11 
12 public class MainActivity extends Activity {
13 
14     @Override
15     protected void onCreate(Bundle savedInstanceState) {
16         super.onCreate(savedInstanceState);
17         setContentView(R.layout.activity_main);
18     }
19 
20     public void click(View view){
21         //resolver相当于中间人
22         ContentResolver resolver = getContentResolver();
23         Uri uri = Uri.parse("content://com.example.mydbtest.personprovider/query");
24         Cursor cursor = resolver.query(uri, null, null, null, null);
25         while(cursor.moveToNext()){
26             String name = cursor.getString(cursor.getColumnIndex("name"));
27             String id = cursor.getString(cursor.getColumnIndex("id"));
28             System.out.println("name=" + name + ", id=" + id);
29         }
30         
31         cursor.close();
32     }
33     
34     public void delete(View view){
35         ContentResolver resolver = getContentResolver();
36         Uri uri = Uri.parse("content://com.example.mydbtest.personprovider/delete");
37         resolver.delete(uri, "name=?", new String[]{"wangwu1"});
38     }
39     
40     public void update(View view){
41         ContentResolver resolver = getContentResolver();
42         Uri uri = Uri.parse("content://com.example.mydbtest.personprovider/update");
43         ContentValues values = new ContentValues();
44         values.put("number", "110");
45         resolver.update(uri, values, "name=?", new String[]{"wangwu3"});
46     }
47     
48     public void insert(View view){
49         ContentResolver resolver = getContentResolver();
50         Uri uri = Uri.parse("content://com.example.mydbtest.personprovider/insert");
51         ContentValues values = new ContentValues();
52         values.put("name", "lisi");
53         values.put("number", "110");
54         values.put("account", 3000);
55         resolver.insert(uri, values);
56     }
57 
58 }