qml读写文件

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

1. 
   #ifndef FILE_OBJECT_H
   
2. 
   #define FILE_OBJECT_H
   


3. 
   #include<QObject>
   


4. 
   classFileObject:publicQObject
   
5. 
   {
   
6. 
   Q_OBJECT
   
7. 
   Q_PROPERTY(QString source READ source WRITE setSource NOTIFY sourceChanged)
   
8. 
   public:
   
9. 
   explicitFileObject(QObject*parent =0);
   


10. 
    Q_INVOKABLE QString read();
    
11. 
    Q_INVOKABLE bool write(constQString& data);
    


12. 
    void setSource(constQString& source){ m_source = source;};
    
13. 
    QString source(){return m_source;}
    


14. 
    signals:
    
15. 
    void sourceChanged(constQString& source);
    


16. 
    private:
    
17. 
    QString m_source;
    
18. 
    };
    


19. 
    #endif// FILE_OBJECT_H
    

2 FileObject.cpp

1. 
   #include"FileObject.h"
   


2. 
   #include<QFile>
   
3. 
   #include<QTextStream>
   


4. 
   FileObject::FileObject(QObject*parent):
   
5. 
   QObject(parent)
   
6. 
   {
   


7. 
   }
   


8. 
   QStringFileObject::read()
   
9. 
   {
   
10. 
    QString content;
    
11. 
    QFile file(m_source);
    
12. 
    if( file.open(QIODevice::ReadOnly)){
    
13. 
    content = file.readAll();
    
14. 
    file.close();
    
15. 
    }
    


16. 
    return content;
    
17. 
    }
    


18. 
    boolFileObject::write(constQString& data)
    
19. 
    {
    
20. 
    QFile file(m_source);
    
21. 
    if( file.open(QFile::WriteOnly|QFile::Truncate)){
    
22. 
    QTextStream out(&file);
    
23. 
    out<<data;
    
24. 
    file.close();
    
25. 
    returntrue;
    
26. 
    }
    
27. 
    else{
    
28. 
    returnfalse;
    
29. 
    }
    
30. 
    }
    

3 注册FileObject到Qml中

1. 
   #include"FileObject.h"
   


2. 
   Q_DECL_EXPORT int main(int argc,char*argv[])
   
3. 
   {
   
4. 
   ...
   
5. 
   qmlRegisterType<FileObject>("FileObject",1,0,"FileObject");
   
6. 
   ...
   
7. 
   }
   

4 在Qml中使用FileObject实例

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

1. 
   importQtQuick1.1
   
2. 
   importFileObject1.0
   


3. 
   Rectangle{
   
4. 
   width:640
   
5. 
   height:320
   


6. 
   Text{
   
7. 
   id: myText
   
8. 
   anchors.centerIn: parent
   
9. 
   }
   


10. 
    FileObject{
    
11. 
    id: fileObject
    
12. 
    source:"test.txt"
    
13. 
    }
    


14. 
    MouseArea{
    
15. 
    anchors.fill: parent
    
16. 
    onClicked:{
    
17. 
    fileObject.write("Hello world!!!");
    
18. 
    myText.text = fileObject.read();
    
19. 
    }
    
20. 
    }
    
21. 
    }