QFile can not open file ,WHY???

I want to save something in local directory at MyDocs/

This is my code,the first code below is correct and add and create txt and content to it.
However the second code went wrong.
[CODE]QDir::setCurrent("/home/user/MyDocs/Documents/"); //Go to this directory
QFile file("lovenote_exp.txt"); //open file,all done correctly
if (!file.open(QIODevice::WriteOnly|QIODevice::Append)) {
qDebug()<< "Cannot open file for writing: " ;
return;
}

QTextStream out(&file);
out<<"\t"<<date<<"\t"<<title<<endl<<"\t"<<text<<endl;
file.close();[/CODE]

The below is the second code, it went wrong.
[CODE]QDir::setCurrent("/home/user/MyDocs/Documents/"); //Go to this directory
QString myfilename="myfile.txt"; // create a QString variant with this value.
QFile file(myfilename); // this is the difference,it went wrong there
if (!file.open(QIODevice::WriteOnly|QIODevice::Append)) {
qDebug()<< "Cannot open file for writing: " ;
return;
}

QTextStream out(&file);
out<<"\t"<<date<<"\t"<<title<<endl<<"\t"<<text<<endl;
file.close();[/CODE]

To be truth,i really dont know what went wrong ....But the second codes still didnt work .Anyone could help me???
It makes me confused.
Help!!!

Does the file exist in /home/user/MyDocs/Documents/?
It clearly says you open for writeonly + append; but you do not give details on how to behave if the file does *not* exist...

[QUOTE=rhythmkay;905973]I want to save something in local directory at MyDocs/


This is my code,the first code below is correct and add and create txt and content to it.
However the second code went wrong.
[CODE]QDir::setCurrent("/home/user/MyDocs/Documents/"); //Go to this directory
QFile file("lovenote_exp.txt"); //open file,all done correctly
if (!file.open(QIODevice::WriteOnly|QIODevice::Append)) {
qDebug()<< "Cannot open file for writing: " ;
return;
}

QTextStream out(&file);
out<<"\t"<<date<<"\t"<<title<<endl<<"\t"<<text<<endl;
file.close();[/CODE]

The below is the second code, it went wrong.
[CODE]QDir::setCurrent("/home/user/MyDocs/Documents/"); //Go to this directory
QString myfilename="myfile.txt"; // create a QString variant with this value.
QFile file(myfilename); // this is the difference,it went wrong there
if (!file.open(QIODevice::WriteOnly|QIODevice::Append)) {
qDebug()<< "Cannot open file for writing: " ;
return;
}

QTextStream out(&file);
out<<"\t"<<date<<"\t"<<title<<endl<<"\t"<<text<<endl;
file.close();[/CODE]

To be truth,i really dont know what went wrong ....But the second codes still didnt work .Anyone could help me???
It makes me confused.
Help!!![/QUOTE]