Qml读写文件_读写文件权限怎么开

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发布于 2022-11-17 05:42:56

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代码可运行

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代码可运行

大家好，又见面了，我是你们的朋友全栈君。

利用qmlRegisterType接口注册一个文件操作类到Qml中，这样Qml就可以实现读写文件。

1 FileObject.h

#ifndef FILE_OBJECT_H
#define FILE_OBJECT_H
#include <QObject>
class FileObject : public QObject
{ 

Q_OBJECT
Q_PROPERTY(QString source READ source WRITE setSource NOTIFY sourceChanged)
public:
explicit FileObject(QObject *parent = 0);
Q_INVOKABLE QString read();
Q_INVOKABLE bool write(const QString& data);
void setSource(const QString& source) { 
 m_source = source; };
QString source() { 
 return m_source; }
signals:
void sourceChanged(const QString& source);
private:
QString m_source;
};
#endif // FILE_OBJECT_H

2 FileObject.cpp

#include "FileObject.h"
#include <QFile>
#include <QTextStream>
FileObject::FileObject(QObject *parent) :
QObject(parent)
{ 

}
QString FileObject::read()
{ 

QString content;
QFile file(m_source);
if ( file.open(QIODevice::ReadOnly) ) { 

content = file.readAll();
file.close();
} 
return content;
}
bool FileObject::write(const QString& data)
{ 

QFile file(m_source);
if ( file.open(QFile::WriteOnly | QFile::Truncate) ) { 

QTextStream out(&file);
out<<data;
file.close();
return true;
}
else { 

return false;
}
}

3 注册FileObject到Qml中

#include "FileObject.h"
Q_DECL_EXPORT int main(int argc, char *argv[])
{ 

...
qmlRegisterType<FileObject>("FileObject", 1, 0, "FileObject");
...
}

4 在Qml中使用FileObject实例

读文件内容fileObject.read();
写文件fileObject.write("Hello world!!!");

import QtQuick 1.1
import FileObject 1.0
Rectangle { 

width: 640
height: 320
Text { 

id: myText
anchors.centerIn: parent
}
FileObject{ 

id: fileObject
source: "test.txt"
}
MouseArea { 

anchors.fill: parent
onClicked: { 

fileObject.write("Hello world!!!");
myText.text =  fileObject.read();
}
}
}