Android之自定义contentprovider

1、ContentProviderTestActivity 类中有2个按钮，分别插入数据为查询数据

2、DataBaseConfiguation 为程序所用到的配置信息注：TableConfiguation内部类实现BaseColumns，即声明了_ID 和 _COUNT

3、MyContentProvider 自定义ContentProvider，继承与ContentProvider

其中 uriMatcher 为Uri的匹配器，在静态块中初始化URI。 columnMap为表结构的映射mapping

在getType方法中要根据访问的Uri确定访问资源的类型，以字符串形式返回。
格式为："vnd.android.cursor.dir/vnd.catking.userList"、"vnd.android.cursor.item/vnd.catking.userItem";

注释掉，对程序运行无影响。

注意：

static{

  //初始化URI
  uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
  uriMatcher.addURI(DataBaseConfiguation.AUTHORITY, "user", USER_LIST_CODE);
  uriMatcher.addURI(DataBaseConfiguation.AUTHORITY, "user/#", USER_RECORD_CODE);
   红色字体中，的格式为xxx/xx，并不是/xxx/xx，其中*号匹配所有字符，#匹配所有数字
  //表结构的映射
  columnMap.put(DataBaseConfiguation.TableConfiguation._ID, DataBaseConfiguation.TableConfiguation._ID);
  columnMap.put(DataBaseConfiguation.TableConfiguation.USER_NAME, DataBaseConfiguation.TableConfiguation.USER_NAME);
}

最后在AndroidManifest.xml里配上

authorities的值必须与DataBaseConfiguation.AUTHORITY一致

ContentProviderTestActivity：

import android.app.Activity;

import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

import com.catking.cfg.DataBaseConfiguation;

public class ContentProviderTestActivity extends Activity {
    private Button insertBtn;
    private Button queryBtn;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        insertBtn = (Button) findViewById(R.id.insert);
        queryBtn = (Button) findViewById(R.id.query);

        insertBtn.setOnClickListener(new InsertOnClickListener());
        queryBtn.setOnClickListener(new QueryOnClickListener());
    }

    class InsertOnClickListener implements OnClickListener{
        @Override
        public void onClick(View v) {
            ContentValues values = new ContentValues();
            values.put(DataBaseConfiguation.TableConfiguation.USER_NAME, "张三");
            Uri uri = getContentResolver().insert(DataBaseConfiguation.TableConfiguation.CONTENT_URI, values);
            System.out.println("uri------------------->" + uri);
        }
    }

    class QueryOnClickListener implements OnClickListener{
        @Override
        public void onClick(View v) {
            Cursor cursor = getContentResolver().query(DataBaseConfiguation.TableConfiguation.CONTENT_URI,
                    null, null, null, null);
            while (cursor.moveToNext()) {
                System.out.println(cursor.getString(cursor.getColumnIndex(DataBaseConfiguation.TableConfiguation.USER_NAME)));
            }
        }

    }
}

DataBaseConfiguation：

package com.catking.cfg;

import android.net.Uri;
import android.provider.BaseColumns;

public class DataBaseConfiguation {
    public static final String AUTHORITY = "com.catking.contentprovider.MyContentProvider";
    public static final String DATABASE_NAME = "cp_db";
    public static final int DATABASE_VERSION = 1;

    public static class TableConfiguation implements BaseColumns{
        public static final String TABLE_NAME = "user";
        public static final Uri CONTENT_URI = Uri.parse("content://" + DataBaseConfiguation.AUTHORITY + "/" + TABLE_NAME);
        public static final String CONTENT_TYPE_DIR = "vnd.android.cursor.dir/vnd.catking.userList";
        public static final String CONTENT_TYPE_RECORD = "vnd.android.cursor.item/vnd.catking.userItem";
        public static final String USER_NAME = "name";
        public static final String DEFAULT_SORT_ORDER = "_id desc";
    }

}

MyContentProvider：

public class MyContentProvider extends ContentProvider {

    private static final UriMatcher uriMatcher;
    private static final int USER_LIST_CODE = 1;
    private static final int USER_RECORD_CODE = 2;
    private SQLiteOpenHelper dbh;
    private static Map<String, String> columnMap = new HashMap<String, String>();

    static{
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        uriMatcher.addURI(DataBaseConfiguation.AUTHORITY, "user", USER_LIST_CODE);
        uriMatcher.addURI(DataBaseConfiguation.AUTHORITY, "user/#", USER_RECORD_CODE);


        columnMap.put(DataBaseConfiguation.TableConfiguation._ID, DataBaseConfiguation.TableConfiguation._ID);
        columnMap.put(DataBaseConfiguation.TableConfiguation.USER_NAME, DataBaseConfiguation.TableConfiguation.USER_NAME);
    }

    @Override
    public boolean onCreate() {
        dbh = new MySQLiteOpenHelper(getContext(), DataBaseConfiguation.DATABASE_NAME, null, DataBaseConfiguation.DATABASE_VERSION);
        System.out.println("dbh ��");
        return true;
    }

    @Override
    public String getType(Uri uri) {
        System.out.println("getTypeִ��");
        switch (uriMatcher.match(uri)) {
        case USER_LIST_CODE:
            return DataBaseConfiguation.TableConfiguation.CONTENT_TYPE_DIR;
        case USER_RECORD_CODE:
            return DataBaseConfiguation.TableConfiguation.CONTENT_TYPE_RECORD;
        default:
            throw new RuntimeException("unknown uri " + uri.toString());
        }
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        System.out.println("insert ִ��");
        SQLiteDatabase db = dbh.getWritableDatabase();
        long rowId = db.insert(DataBaseConfiguation.TableConfiguation.TABLE_NAME, null, values);
        if (rowId > 0) {
            Uri insertedUri = ContentUris.withAppendedId(DataBaseConfiguation.TableConfiguation.CONTENT_URI, rowId);
            getContext().getContentResolver().notifyChange(insertedUri, null);
            return insertedUri;
        }
        throw new SQLException("fail to insert row into " + uri.toString());
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
        System.out.println(DataBaseConfiguation.TableConfiguation.CONTENT_URI);
        SQLiteDatabase db = dbh.getReadableDatabase();
        SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
        qb.setTables(DataBaseConfiguation.TableConfiguation.TABLE_NAME);
        qb.setProjectionMap(columnMap);
        switch (uriMatcher.match(uri)) {
        case USER_LIST_CODE:
            break;
        case USER_RECORD_CODE:
            System.out.println("��ʼ��ѯuri.getPathSegments()��");
            for (String s : uri.getPathSegments()) {
                System.out.println(s);
            }
            System.out.println("��ѯuri.getPathSegments()��");
            qb.appendWhere(DataBaseConfiguation.TableConfiguation.USER_NAME + "=" + uri.getPathSegments().get(1));
            break;
        default:
            throw new RuntimeException("unknown uri " + uri.toString());
        }
        Cursor c = db.query(DataBaseConfiguation.TableConfiguation.TABLE_NAME, projection, selection, selectionArgs, null, null,
                DataBaseConfiguation.TableConfiguation.DEFAULT_SORT_ORDER);
        c.setNotificationUri(getContext().getContentResolver(), uri);
        return c;
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        // TODO Auto-generated method stub
        return 0;
    }

}

MySQLiteOpenHelper：

public class MySQLiteOpenHelper extends SQLiteOpenHelper {

    public MySQLiteOpenHelper(Context context, String name, CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        System.out.println("createDB excuted");
        String createSQL = "create table " + DataBaseConfiguation.TableConfiguation.TABLE_NAME + "("
                + DataBaseConfiguation.TableConfiguation._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                + DataBaseConfiguation.TableConfiguation.USER_NAME + " VARCHAR(20)" + ")";
        System.out.println(createSQL);
        db.execSQL(createSQL);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        System.out.println("onUpgrade excuted");
    }

}

AndroidManifest：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.catking.activity"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".ContentProviderTestActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <provider android:authorities="com.catking.contentprovider.MyContentProvider" android:name="com.catking.contentprovider.MyContentProvider" />
    </application>

</manifest>

参考自：http://catkingwong.iteye.com/blog/1313740