QSqlRelationalTableModel顯示一個圖標而不是數據

我正在顯示一個包含一個blob（pdf文件）列的表。我可以隱藏用戶的列，但是我想在列中顯示一個文件時顯示一個圖標。我subclassed QsqlRealtionalTableModel並重載數據函數。如下所示。我的問題是，現在該圖標與來自PDF的亂碼數據一起顯示。我認爲這個超載函數正在代替數據的圖標。QSqlRelationalTableModel顯示一個圖標而不是數據

QVariant RelationalTableModelWithIcon::data(const QModelIndex &item, int role) const 
{ 
    if(item.column() == 3 && role == Qt::DecorationRole) 
    { 
     QSqlRecord r= record(item.row()); 
     QByteArray a= r.field(3).value().toByteArray(); 
     QIcon icon = QIcon(":/icons/Art/Icons/Iynque-Flat-Ios7-Style-Documents-Pdf.ico"); 
     if(a.isNull() == false) 
     { 
      return QVariant(icon); 
     } 
    } 
    return QSqlRelationalTableModel::data(item,role); 
}

DROP TABLE IF EXISTS `ComOper`.`documentsqueue` ; 

CREATE TABLE IF NOT EXISTS `ComOper`.`documentsqueue` (
    `iddocumentsqueue` INT NOT NULL AUTO_INCREMENT, 
    `iddocument` INT NULL DEFAULT 1, 
    `name` VARCHAR(45) NOT NULL, 
    `image` MEDIUMBLOB NULL, 
    `dateEntered` DATE NULL, 
    `dateExpired` DATE NULL, 
    `dateApproved` DATE NULL, 
    `notes` MEDIUMTEXT NULL, 
    `archived` TINYINT NULL DEFAULT 0, 
    `iddocType` INT NOT NULL DEFAULT 1, 
    `idsupplier` INT NOT NULL, 
    `idfacilities` INT NOT NULL DEFAULT 1, 
    `idproducts` INT NOT NULL DEFAULT 1, 
    `iduser` INT NOT NULL DEFAULT 1, 
    PRIMARY KEY (`iddocumentsqueue`), 
    CONSTRAINT `fk_documentsqueue_docType1` 
    FOREIGN KEY (`iddocType`) 
    REFERENCES `ComOper`.`docType` (`iddocType`) 
    ON DELETE NO ACTION 
    ON UPDATE NO ACTION, 
    CONSTRAINT `fk_documentsqueue_documents1` 
    FOREIGN KEY (`iddocument`) 
    REFERENCES `ComOper`.`documents` (`iddocument`) 
    ON DELETE NO ACTION 
    ON UPDATE NO ACTION, 
    CONSTRAINT `fk_documentsqueue_user1` 
    FOREIGN KEY (`iduser`) 
    REFERENCES `ComOper`.`user` (`iduser`) 
    ON DELETE NO ACTION 
    ON UPDATE NO ACTION, 
    CONSTRAINT `fk_documentsqueue_products1` 
    FOREIGN KEY (`idproducts`) 
    REFERENCES `ComOper`.`products` (`idproducts`) 
    ON DELETE NO ACTION 
    ON UPDATE NO ACTION, 
    CONSTRAINT `fk_documentsqueue_facilities1` 
    FOREIGN KEY (`idfacilities`) 
    REFERENCES `ComOper`.`facilities` (`idfacilities`) 
    ON DELETE NO ACTION 
    ON UPDATE NO ACTION, 
    CONSTRAINT `fk_documentsqueue_supplier1` 
    FOREIGN KEY (`idsupplier`) 
    REFERENCES `ComOper`.`supplier` (`idsupplier`) 
    ON DELETE NO ACTION 
    ON UPDATE NO ACTION)

來源

2017-08-29 Dan3460

你可以共享數據庫請測試你的代碼，我想你正在使用sqlite作爲數據庫。 – eyllanesc

我從MySql工作臺添加了create語句。 – Dan3460

其實這並沒有什麼幫助，我已經看到在你使用該數據庫的幾篇文章中，我建議在你想問的時候在sqlite中做一個測試數據庫。 – eyllanesc

讓你不顯示時，他們索要Qt::DisplayRole角色，當他們索要Qt::DecorationRole角色返回圖標，你必須返回一個空字符串PDF的不可讀的文本。我還建議只有一次讀書的圖標，如果它是獨一無二的，這我在下面：

的* .h

private: 
    QIcon icon;

*的.cpp

RelationalTableModelWithIcon::RelationalTableModelWithIcon(QObject *parent, QSqlDatabase db): 
    QSqlRelationalTableModel(parent, db) 
{ 
    icon = QIcon(":/icons/Art/Icons/Iynque-Flat-Ios7-Style-Documents-Pdf.ico"); 
} 
QVariant RelationalTableModelWithIcon::data(const QModelIndex &index, int role) const 
{ 
    if(index.column() == 3){ 
     if(role == Qt::DisplayRole) 
      return ""; 
     else if (role == Qt::DecorationRole) 
      return icon; 
    } 
    return QSqlRelationalTableModel::data(index, role); 
}

來源

2017-08-29 02:27:12 eyllanesc

就是這樣，完美地工作。非常感謝 – Dan3460

QSqlRelationalTableModel顯示一個圖標而不是數據

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