[Android Pro] 内容提供者ContentProvider的基本使用

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <data android:mimeType="vnd.android.cursor.dir/person" />
            </intent-filter>
            <intent-filter>
                <data android:mimeType="vnd.android.cursor.item/person" />
            </intent-filter>
        </activity>
        <!-- 配置内容提供者,android:authorities为该内容提供者取名作为在本应用中的唯一标识 -->
        <provider android:name=".providers.PersonProvider" 
            android:authorities="cn.xyCompany.providers.personProvider"/>
    </application>

内容提供者
package cn.xy.cotentProvider.app.providers;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.util.Log;
import cn.xy.cotentProvider.service.DBOpeningHelper;

/**
 * contentProvider作为一种组件必须放在应用所在包或其子包下，主要作用是对外共享数据
 * 测试步骤1：将本项目先部署
 * 测试步骤2：调用测试方法
 * @author xy
 * 
 */
public class PersonProvider extends ContentProvider
{
    private DBOpeningHelper dbHelper;

    // 若不匹配采用UriMatcher.NO_MATCH(-1)返回
    private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);

    // 匹配码
    private static final int CODE_NOPARAM = 1;
    private static final int CODE_PARAM = 2;

    static
    {
        // 对等待匹配的URI进行匹配操作，必须符合cn.xyCompany.providers.personProvider/person格式
        // 匹配返回CODE_NOPARAM，不匹配返回-1
        MATCHER.addURI("cn.xyCompany.providers.personProvider", "person", CODE_NOPARAM);

        // #表示数字 cn.xyCompany.providers.personProvider/person/10
        // 匹配返回CODE_PARAM，不匹配返回-1
        MATCHER.addURI("cn.xyCompany.providers.personProvider", "person/#", CODE_PARAM);
    }

    @Override
    public boolean onCreate()
    {
        dbHelper = new DBOpeningHelper(this.getContext());
        return true;
    }

    /**
     * 外部应用向本应用插入数据
     */
    @Override
    public Uri insert(Uri uri, ContentValues values)
    {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        switch (MATCHER.match(uri))
        {
            case CODE_NOPARAM:
                // 若主键值是自增长的id值则返回值为主键值，否则为行号，但行号并不是RecNo列
                long id = db.insert("person", "name", values); 
                Uri insertUri = ContentUris.withAppendedId(uri, id); 
                return insertUri;
            default:
                throw new IllegalArgumentException("this is unkown uri:" + uri);
        }
    }

    /**
     * 外部应用向本应用删除数据
     */
    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs)
    {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        switch (MATCHER.match(uri))
        {
            case CODE_NOPARAM:
                return db.delete("person", selection, selectionArgs); // 删除所有记录
            case CODE_PARAM:
                long id = ContentUris.parseId(uri); // 取得跟在URI后面的数字
                Log.i("provider", String.valueOf(id));
                String where = "id = " + id;
                if (null != selection && !"".equals(selection.trim()))
                {
                    where += " and " + selection;
                }
                return db.delete("person", where, selectionArgs);
            default:
                throw new IllegalArgumentException("this is unkown uri:" + uri);
        }
    }

    /**
     * 外部应用向本应用更新数据
     */
    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)
    {
        SQLiteDatabase db = dbHelper.getWritableDatabase();
        switch (MATCHER.match(uri))
        {
            case CODE_NOPARAM:
                return db.update("person",values,selection, selectionArgs); // 更新所有记录
            case CODE_PARAM:
                long id = ContentUris.parseId(uri); // 取得跟在URI后面的数字
                String where = "id = " + id;
                if (null != selection && !"".equals(selection.trim()))
                {
                    where += " and " + selection;
                }
                return db.update("person",values,where,selectionArgs);
            default:
                throw new IllegalArgumentException("this is unkown uri:" + uri);
        }
    }
    
    /**
     * 返回对应的内容类型
     * 如果返回集合的内容类型，必须以vnd.android.cursor.dir开头
     * 如果是单个元素，必须以vnd.android.cursor.item开头
     */
    @Override
    public String getType(Uri uri)
    {
        switch(MATCHER.match(uri))
        {
            case CODE_NOPARAM:
                return "vnd.android.cursor.dir/person";
            case CODE_PARAM:
                return "vnd.android.cursor.item/person";
            default:
                throw new IllegalArgumentException("this is unkown uri:" + uri);
        }
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
    {
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        switch (MATCHER.match(uri))
        {
            case CODE_NOPARAM:
                return db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
            case CODE_PARAM:
                long id = ContentUris.parseId(uri); // 取得跟在URI后面的数字
                String where = "id = " + id;
                if (null != selection && !"".equals(selection.trim()))
                {
                    where += " and " + selection;
                }
                return db.query("person", projection, where, selectionArgs, null, null, sortOrder);
            default:
                throw new IllegalArgumentException("this is unkown uri:" + uri);
        }
    }

}



测试代码
package cn.xy.test.test;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.test.AndroidTestCase;
import android.util.Log;

/**
 * 测试代码
 * @author xy
 *
 */
public class TestProviders extends AndroidTestCase
{
    // 在执行该测试方法时需要先将还有内容提供者的项目部署到Android中，否则无法找到内容提供者
    public void testInsert()
    {
        Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person");
        ContentResolver resolver = this.getContext().getContentResolver();
        ContentValues values = new ContentValues();
        values.put("name", "xy");
        values.put("phone", "111");
        resolver.insert(uri, values); // 内部调用内容提供者的insert方法
    }

    // 不带id参数的删除
    public void testDelete1()
    {
        Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person");
        ContentResolver resolver = this.getContext().getContentResolver();
        int rowAffect = resolver.delete(uri, null, null);
        Log.i("rowAffect", String.valueOf(rowAffect));
    }

    // 带参数的删除，通过URI传递了id至contentProvider并可追加其他条件
    public void testDelete2()
    {
        Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person/18");
        ContentResolver resolver = this.getContext().getContentResolver();
        int rowAffect = resolver.delete(uri, "name = ?", new String[] { "XY2" }); // 在provider中手动进行了拼装
        Log.i("rowAffect", String.valueOf(rowAffect));
    }
    
    public void testUpdate()
    {
        Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person/19");
        ContentResolver resolver = this.getContext().getContentResolver();
        ContentValues values = new ContentValues();
        values.put("name", "newxy");
        values.put("phone", "new111");
        int rowAffect = resolver.update(uri, values, null, null);
        Log.i("rowAffect", String.valueOf(rowAffect));
    }
    
    public void testQuery()
    {
        Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person/19");
        ContentResolver resolver = this.getContext().getContentResolver();
        Cursor cursor = resolver.query(uri, new String[]{"id","name","phone"}, null, null, "id asc");
        if(cursor.moveToFirst())
        {
            Log.i("query", cursor.getString(cursor.getColumnIndex("name")));
        }
        cursor.close();
    }
}