自定义ContentProvider

1,继承 COntentProvider

public class PersonContentProvider extends ContentProvider 

实现他的方法；

2,配置清单文件

<provider
            android:name=".providers.PersonContentProvider"
            android:authorities="com.itheima28.sqlitedemo.providers.PersonContentProvider"
            android:readPermission="aa.bb.cc.read"
            android:writePermission="aa.bb.cc.write" >
        </provider>

设置权限android:readPermission=”aa.bb.cc.read”
android:writePermission=”aa.bb.cc.write” >

3，在onCreate里面实例化，数据库帮助对象

    @Override
    public boolean onCreate() {
        mOpenHelper = new PersonSQLiteOpenHelper(getContext());
        return true;
    }

4，实现 对外 操作的接口

private static final String AUTHORITY = "com.itheima28.sqlitedemo.providers.PersonContentProvider";
private static final int PRESON_INSERT_CODE = 0;    // 操作person表添加的操作的uri匹配码
    private static final int PERSON_DELETE_CODE = 1;
    private static final int PERSON_UPDATE_CODE = 2;
    private static final int PERSON_QUERY_ALL_CODE = 3;
    private static final int PERSON_QUERY_ITEM_CODE = 4;

    private static UriMatcher uriMatcher;
    private PersonSQLiteOpenHelper mOpenHelper;     // person表的数据库帮助对象

    static {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

        // 添加一些uri(分机号)

        // content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/insert
        uriMatcher.addURI(AUTHORITY, "person/insert", PRESON_INSERT_CODE);

        // content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/delete
        uriMatcher.addURI(AUTHORITY, "person/delete", PERSON_DELETE_CODE);

        // content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/update
        uriMatcher.addURI(AUTHORITY, "person/update", PERSON_UPDATE_CODE);

        // content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/queryAll
        uriMatcher.addURI(AUTHORITY, "person/queryAll", PERSON_QUERY_ALL_CODE);

        // content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/#
        uriMatcher.addURI(AUTHORITY, "person/query/#", PERSON_QUERY_ITEM_CODE);
    }

5，

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {
        SQLiteDatabase db = mOpenHelper.getReadableDatabase();
        switch (uriMatcher.match(uri)) {
        case PERSON_QUERY_ALL_CODE:  // 查询所有人的uri
            if(db.isOpen()) {
                Cursor cursor = db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
                return cursor;
                // db.close(); 返回cursor结果集时, 不可以关闭数据库
            }
            break;
        case PERSON_QUERY_ITEM_CODE:        // 查询的是单条数据, uri末尾出有一个id
            if(db.isOpen()) {
                //取出井号的那个id         #
                long id = ContentUris.parseId(uri);

                Cursor cursor = db.query("person", projection, "_id = ?", new String[]{id + ""}, null, null, sortOrder);

                return cursor;
            }
            break;
        default:
            throw new IllegalArgumentException("uri不匹配: " + uri);
        }
        return null;
    }

    @Override
    public String getType(Uri uri) {
        switch (uriMatcher.match(uri)) {
        case PERSON_QUERY_ALL_CODE: // 返回多条的MIME-type
            return "vnd.android.cursor.dir/person";
        case PERSON_QUERY_ITEM_CODE: // 返回单条的MIME-TYPE
            return "vnd.android.cursor.item/person";
        default:
            break;
        }
        return null;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {

        switch (uriMatcher.match(uri)) {
        case PRESON_INSERT_CODE:    // 添加人到person表中
            SQLiteDatabase db = mOpenHelper.getWritableDatabase();

            if(db.isOpen()) {

                long id = db.insert("person", null, values);

                db.close();

                return ContentUris.withAppendedId(uri, id);
            }
            break;
        default:
            throw new IllegalArgumentException("uri不匹配: " + uri);
        }
        return null;
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        switch (uriMatcher.match(uri)) {
        case PERSON_DELETE_CODE:    // 在person表中删除数据的操作
            SQLiteDatabase db = mOpenHelper.getWritableDatabase();
            if(db.isOpen()) {
                int count = db.delete("person", selection, selectionArgs);
                db.close();
                return count;
            }
            break;
        default:
            throw new IllegalArgumentException("uri不匹配: " + uri);
        }
        return 0;
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
            String[] selectionArgs) {
        switch (uriMatcher.match(uri)) {
        case PERSON_UPDATE_CODE: // 更新person表的操作
            SQLiteDatabase db = mOpenHelper.getWritableDatabase();
            if(db.isOpen()) {
                int count = db.update("person", values, selection, selectionArgs);
                db.close();
                return count;
            }
            break;
        default:
            throw new IllegalArgumentException("uri不匹配: " + uri);
        }
        return 0;
    }

6，其他 app 访问该数据库

其他应用来使用的方法；
 package com.itheima28.othercontentprovider;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.test.AndroidTestCase;
import android.util.Log;

public class TextCase extends AndroidTestCase {

    private static final String TAG = "TextCase";

    public void testInsert() {
        //相当于得到ContenProvider的号码、、、即得到上面那个文件夹.PersonContentProvider的号码、、、、、
        Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/insert");

        // 内容提供者访问对象
        ContentResolver resolver = getContext().getContentResolver();

        ContentValues values = new ContentValues();
        values.put("name", "fengjie");
        values.put("age", 90);

        uri = resolver.insert(uri, values);
        Log.i(TAG, "uri: " + uri);
        long id = ContentUris.parseId(uri);
        Log.i(TAG, "添加到: " + id);
    }

    public void testDelete() {
        Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/delete");

        // 内容提供者访问对象
        ContentResolver resolver = getContext().getContentResolver();

        String where = "_id = ?";
        String[] selectionArgs = {"21"};
        int count = resolver.delete(uri, where, selectionArgs);
        Log.i(TAG, "删除行: " + count);
    }

    public void testUpdate() {
        Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/update");

        // 内容提供者访问对象
        ContentResolver resolver = getContext().getContentResolver();

        ContentValues values = new ContentValues();
        values.put("name", "lisi");

        int count = resolver.update(uri, values, "_id = ?", new String[]{"20"});
        Log.i(TAG, "更新行: " + count);
    }

    public void testQueryAll() {
        Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/queryAll");

        // 内容提供者访问对象
        ContentResolver resolver = getContext().getContentResolver();

        Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, "_id desc");

        if(cursor != null && cursor.getCount() > 0) {

            int id;
            String name;
            int age;
            while(cursor.moveToNext()) {
                id = cursor.getInt(0);
                name = cursor.getString(1);
                age = cursor.getInt(2);
                Log.i(TAG, "id: " + id + ", name: " + name + ", age: " + age);
            }
            cursor.close();
        }
    }

    public void testQuerySingleItem() {
        Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/#");

        // 在uri的末尾添加一个id content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/20
        uri = ContentUris.withAppendedId(uri, 20);

        // 内容提供者访问对象
        ContentResolver resolver = getContext().getContentResolver();

        Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, null);

        if(cursor != null && cursor.moveToFirst()) {
            int id = cursor.getInt(0);
            String name = cursor.getString(1);
            int age = cursor.getInt(2);
            cursor.close();
            Log.i(TAG, "id: " + id + ", name: " + name + ", age: " + age);
        }
    }
}

NODE: 上面设置了权限访问，所以，其他的应用访问要 在清单文件，配置访问权限。