How to get file name in Qt? - c++

Question

I have modified the Text Finder example which I got from a Qt Tutorial and made a Text Viewer. In this program, the user types in the address of the file and clicks the Search button. The program then displays the content of the text file. Below is my code.
text_finder.cpp:
#include "text_finder.h"
#include "ui_text_finder.h"
#include <QHBoxLayout>
#include <QFile>
#include <QTextStream>
#include <QFileDialog>
Text_Finder::Text_Finder(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::Text_Finder)
{
ui->setupUi(this);
}
Text_Finder::~Text_Finder()
{
delete ui;
}
void Text_Finder::loadFile(QFile file){ // I have to pass the file name as parameter.
QFile inputFile(file);
inputFile.open(QIODevice::ReadOnly);
QTextStream in(&inputFile);
QString line = in.readAll();
inputFile.close();
ui->read->setText(line);
QTextCursor cursor = ui->read->textCursor();
cursor.movePosition(QTextCursor::Start, QTextCursor::MoveAnchor, 1);
}
void Text_Finder::on_search_clicked()
{
// Code that gets the path from the text box.
loadFile();//Parameters not passed yet.
}
I have not yet entered the code which gets the name of the file from the address of the text box. I will have to pass the file to the loadFile() function which will enter the contents into the Text Edit in the center of the program. I want a solution to get the name of the file of which the user enters. For example, the user might enter, "/home/user/input.txt". The program should get the contents of that file and forward it to loadFile(). An solution with an explanation on how the various parts work is needed. I am using Qt Creator on Ubuntu 15.04 (Beta).

Answer 1

If i understand you correctly, the user types the full path or address of the file in the text box and you want to get just the name of the file out of the full path the user entered.
EDIT: I realized using 'QFileDialog' was the ideal way to get the file name. So this
is how i redesigned the whole code;
text_finder.h
#ifndef TEXT_FINDER_H
#define TEXT_FINDER_H
#include <QDialog>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QPushButton>
#include <QLineEdit>
#include <QTextEdit>
#include <QFile>
#include <QTextStream>
#include <QFileDialog>
class Text_Finder : public QWidget{
Q_OBJECT
public:
Text_Finder(QWidget *parent = 0);
~Text_Finder();
public slots:
void on_search_clicked();
void open();
//void loadFile(QString const &filename);
private:
void loadFile(QString const &filename);
QLineEdit *txtFileName;
QTextEdit *txtFileContents;
QString fileName;
QPushButton *search;
QPushButton *openFile;
};
#endif
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
class MainWindow : public QMainWindow {
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
};
#endif // MAINWINDOW_H
text_finder.cpp
#include "text_finder.h"
Text_Finder::Text_Finder(QWidget *parent) : QWidget(parent) {
openFile = new QPushButton("Open File");
connect(openFile, SIGNAL(clicked()), this, SLOT(open()));
txtFileName = new QLineEdit;
search = new QPushButton("&Search");
txtFileContents = new QTextEdit;
QHBoxLayout *dialogAndViewLayout = new QHBoxLayout;
dialogAndViewLayout->addWidget(openFile);
dialogAndViewLayout->addWidget(txtFileName);
dialogAndViewLayout->addStretch();
dialogAndViewLayout->addWidget(search);
QVBoxLayout *layout = new QVBoxLayout;
layout->addLayout(dialogAndViewLayout);
layout->addWidget(txtFileContents);
connect(search, SIGNAL(clicked()), this, SLOT(on_search_clicked()));
setLayout(layout);
}
Text_Finder::~Text_Finder(){
delete txtFileName;
delete txtFileContents;
delete search;
delete openFile;
}
void Text_Finder::loadFile(QString const &filename){
QFile inputFile(filename);
inputFile.open(QIODevice::ReadWrite | QIODevice::Text);
QTextStream textStream(&inputFile);
QString contents = textStream.readAll();
inputFile.close();
txtFileContents->setPlainText(contents);
}
void Text_Finder::on_search_clicked() {
loadFile(fileName);
}
/*this slot opens a file dialog. After the file has been selected, it sets
the file to the text text edit box*/
void Text_Finder::open() {
fileName = QFileDialog::getOpenFileName(this, "Open text", "/home/",
"");
txtFileName->setText(fileName);
}
mainwindow.cpp
#include "mainwindow.h"
#include "text_finder.h"
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) {
Text_Finder *textFinder = new Text_Finder;
setCentralWidget(textFinder);
}
MainWindow::~MainWindow() {
}
Finally
main.cpp
#include "text_finder.h"
#include <QApplication>
int main(int argc, char **argv){
QApplication app(argc, argv);
Text_Finder *window = new Text_Finder;
window->show();
return app.exec();
}

Answer 2

Unless you're going to do some programmatic editing, you do not need to use QTextCursor at all.
I suggest you have a browse through the reference manual before trying to carry on since it's clear that you are not familiar with the bare-basics of the graphical widgets you're using.
If you're only reading in a file name and then displaying the contents in plain text format, this is all you need to do. (I'm assuming your filename is entered into a QLineEdit widget and ui->read is a QTextEdit widget)
void Text_Finder::loadFile(QString const &filename){ // I have to pass the file name as parameter.
QFile inputFile(filename);
inputFile.open(QIODevice::ReadOnly);
QTextStream in(&inputFile);
QString contents = in.readAll();
inputFile.close();
ui->read->setPlainText(contents);
}
void Text_Finder::on_search_clicked()
{
QString filename = ui->filename->text();
loadFile(filename);
}
EDIT:
I've created a fully-functional remake of your code, incorporating the changes I suggested. I have compiled and tested it and it is working as per your description.
Note: In the absence of your UI file, I've created the user interface manually.
text_finder.h
#ifndef TEXT_FINDER_H
#define TEXT_FINDER_H
#include <QMainWindow>
class QLineEdit;
class QTextEdit;
class Text_Finder : public QMainWindow{
Q_OBJECT
public:
Text_Finder(QWidget *parent = 0);
~Text_Finder();
public slots:
void on_search_clicked();
private:
void loadFile(QString const &filename);
QLineEdit *txtFileName;
QTextEdit *txtFileContents;
};
#endif // TEXT_FINDER_H
main.cpp
#include "text_finder.h"
#include <QApplication>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QPushButton>
#include <QLineEdit>
#include <QTextEdit>
#include <QFile>
#include <QTextStream>
Text_Finder::Text_Finder(QWidget *parent) :
QMainWindow(parent)
{
QWidget *ui = new QWidget(this);
QHBoxLayout *hLayout = new QHBoxLayout;
txtFileName = new QLineEdit(this);
QPushButton *loadButton = new QPushButton("Load File", this);
connect(loadButton, &QPushButton::clicked, this, &Text_Finder::on_search_clicked);
hLayout->addWidget(txtFileName);
hLayout->addWidget(loadButton);
QVBoxLayout *vLayout = new QVBoxLayout(this);
vLayout->addLayout(hLayout);
txtFileContents = new QTextEdit(this);
vLayout->addWidget(txtFileContents);
ui->setLayout(vLayout);
setCentralWidget(ui);
}
Text_Finder::~Text_Finder(){
// It's not necessary to explicitly delete any widgets.
// QObject implements the Composite Pattern, which takes care of all this automatically
}
void Text_Finder::loadFile(QString const &filename){
QFile inputFile(filename);
inputFile.open(QIODevice::ReadOnly);
QTextStream in(&inputFile);
QString contents = in.readAll();
inputFile.close();
txtFileContents->setPlainText(contents);
}
void Text_Finder::on_search_clicked()
{
QString filename = txtFileName->text();
loadFile(filename);
}
int main(int argc, char **argv){
QApplication app(argc, argv);
Text_Finder w;
w.show();
return app.exec();
}
HINT for future questions: You will get better answers quicker if you include an SSCCE in your question. What I've included in this edit is a suitable example.