android - Android DBFlow 和 CursorLoader

Question

任何人都知道如何将 cursorLoader 与 DBFlow 一起使用？我看到了这个问题，但这并没有添加到 DBFlow 中。

谢谢。

score 1 · Accepted Answer

你可以在这里找到官方文档，或者你可以按照我的方式实现它

使用 DBFlow 版本 3

//我已经编辑了我的答案并为下面的内容提供者部分提供了更简单的方法

将此添加到应用程序内的清单

<provider
        android:authorities="com.hashx19.pristinekashmir.mycontentprovider"
        android:exported="false"
        android:name=".MyContentProvider"/>

创建名为 MyContentProvider 的 java 文件并在其中复制以下代码并根据您的项目替换 AUTHORITY ,ENDPOINT, AppDatabase(Your database name) ,TableClassName 。

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.CursorIndexOutOfBoundsException;
import android.net.Uri;

import com.hashx19.pristinekashmir.MySQLiteHelper;
import com.raizlabs.android.dbflow.annotation.ConflictAction;
import com.raizlabs.android.dbflow.config.FlowManager;
import com.raizlabs.android.dbflow.structure.ModelAdapter;

import java.util.Arrays;
import java.util.HashSet;

/**
 * Created by Filu on 8/25/2016.
 */

public class MyContentProvider extends ContentProvider {

    public static final String AUTHORITY = "com.hashx19.pristinekashmir.mycontentprovider";

    private static final String ENDPOOINT = "feeds";

    // @ContentUri(path = ENDPOOINT, type = ContentUri.ContentType.VND_MULTIPLE + ENDPOOINT)



    public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY
            + "/" + ENDPOOINT);



    private static final int feeds_CONTENT_URI = 0;

    private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);
    static {
        MATCHER.addURI(AUTHORITY, ENDPOOINT, feeds_CONTENT_URI);
    }
    ;



    @Override
    public final String getType(Uri uri) {
        String type = null;
        switch(MATCHER.match(uri)) {
            case feeds_CONTENT_URI: {
                type = "vnd.android.cursor.dir/" +ENDPOINT;
                break;
            }
            default: {
                throw new IllegalArgumentException("Unknown URI" + uri);
            }
        }
        return type;
    }

@Override
public boolean onCreate() {
    return false;
}


@Override
public final Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
    android.database.Cursor cursor = null;
    switch(MATCHER.match(uri)) {
        case feeds_CONTENT_URI: {
            cursor = FlowManager.getDatabase("AppDatabase").getWritableDatabase().query("TableClassName", projection, selection, selectionArgs, null, null, sortOrder);
            break;
        }
    }
    if (cursor != null) {
        cursor.setNotificationUri(getContext().getContentResolver(), uri);
    }
    return cursor;
}

@Override
public final Uri insert(Uri uri, ContentValues values) {
    switch(MATCHER.match(uri)) {
        case feeds_CONTENT_URI: {
            ModelAdapter adapter = FlowManager.getModelAdapter(FlowManager.getTableClassForName("AppDatabase", "TableClassName"));
            final long id = FlowManager.getDatabase("AppDatabase").getWritableDatabase().insertWithOnConflict("TableClassName", null, values, ConflictAction.getSQLiteDatabaseAlgorithmInt(adapter.getInsertOnConflictAction()));
            getContext().getContentResolver().notifyChange(uri, null);
            return ContentUris.withAppendedId(uri, id);
        }
        default: {
            throw new IllegalStateException("Unknown Uri" + uri);
        }
    }
}


@Override
public final int delete(Uri uri, String selection, String[] selectionArgs) {
    switch(MATCHER.match(uri)) {
        case feeds_CONTENT_URI: {
            long count = FlowManager.getDatabase("AppDatabase").getWritableDatabase().delete("TableClassName", selection, selectionArgs);
            if (count > 0) {
                getContext().getContentResolver().notifyChange(uri, null);
            }
            return (int) count;
        }
        default: {
            throw new IllegalArgumentException("Unknown URI" + uri);
        }
    }
}

@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
    switch(MATCHER.match(uri)) {
        case feeds_CONTENT_URI: {
            ModelAdapter adapter = FlowManager.getModelAdapter(FlowManager.getTableClassForName("AppDatabase", "TableClassName"));
            long count = FlowManager.getDatabase("AppDatabase").getWritableDatabase().updateWithOnConflict("TableClassName", values, selection, selectionArgs, ConflictAction.getSQLiteDatabaseAlgorithmInt(adapter.getUpdateOnConflictAction()));
            if (count > 0) {
                getContext().getContentResolver().notifyChange(uri, null);
            }
            return (int) count;
        }
        default: {
            throw new IllegalStateException("Unknown Uri" + uri);
        }
    }
}
}

然后在覆盖 Loader 方法时做这样的事情

getLoaderManager().initLoader(1, null, this);




@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {

    String selection, sortOrder;
    String[] selectionArgs, projection;


    selection = ...;

    selectionArgs = ...;

    sortOrder = ...;


    projection= new String[]{"id","date", "link","title","content","excerpt","author",};

    CursorLoader cursorLoader = new CursorLoader(getContext(),MyContentProvider.CONTENT_URI, projection,null,null,null);


    return cursorLoader;
}

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {

TableClass post = new TableClass();


      while (!cursor.isAfterLast()) {
      try{
        post.setId(cursor.getInt(cursor.getColumnIndex("id")));



     }catch (NullPointerException e){
          e.printStackTrace();
    }catch (CursorIndexOutOfBoundsException c){
          c.printStackTrace();
    }


     }


}
@Override
public void onLoaderReset(Loader<Cursor> loader) {

}

已编辑

想出更简单的方法来实现内容提供者。

如果您已经添加了提供程序代码，请将其添加到您的清单中/或以这种方式修改。

将您的 AppDatabase 类修改为

@ContentProvider(authority = AppDatabase.AUTHORITY,
            database = AppDatabase.class,
            baseContentUri = AppDatabase.BASE_CONTENT_URI)
    @Database(name = AppDatabase.NAME, version = AppDatabase.VERSION)
    public class AppDatabase {

        public static final String NAME = "AppDatabase"; // we will add the .db extension

        public static final int VERSION = 2;

        public static final String AUTHORITY = "com.hashx19.pristinekashmir.dbflowcontentprovider";

        public static final String BASE_CONTENT_URI = "content://"; }

将您要用作提供者的每个表修改为

@TableEndpoint(name = PostData.ENDPOINT, contentProvider =      AppDatabase.class)

@Table(database =   AppDatabase.class ,allFields = true ,name = PostData.ENDPOINT)



public class PostData extends BaseModel {

    public static final String ENDPOINT = "PostData";
    @ContentUri(path = ENDPOINT, type = ContentUri.ContentType.VND_MULTIPLE + ENDPOINT)
    public static final Uri CONTENT_URI = Uri.parse(AppDatabase.BASE_CONTENT_URI + AppDatabase.AUTHORITY
            + "/" + ENDPOINT);

@PrimaryKey
    public int id;
    public  String image;

}

对于在 Cursor Loader 中使用内容提供程序，请使用 TableName.CONTENT_URI，如本例所示

 CursorLoader cursorLoader = new       CursorLoader(getContext(),PostData.CONTENT_URI,projection,null,null,null);

android - Android DBFlow 和 CursorLoader

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