[游戏开发]Qt（九）文件夹与文件（显示图像）

一、UI布局

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QFileDialog>
#include <QTreeWidgetItem>
#include <QTreeWidget>
#include <QPixmap>
#include <QLabel>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT
private:
    enum treeItemType {itTopItem=1001,itGroupItem,itImageItem};
    enum treeColNum {colItem=0,colItemType=1};
    QPixmap pixmap;
    QLabel  labFileName;
    float pixRatio;

    void changeItemCaption(QTreeWidgetItem *item);
public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_actOpenFolder_triggered();

    void on_actOpenFile_triggered();

    void on_treeWidget_currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous);

    void on_actWidth_triggered();

    void on_actIter_triggered();

    void on_actDel_triggered();

    void on_actHeight_triggered();

    void on_actZoomIn_triggered();

    void on_actZoomOut_triggered();

    void on_actRealSize_triggered();

private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"


MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->statusbar->addWidget(&labFileName);
}

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_actOpenFolder_triggered()
{
    QString fullname = QFileDialog::getExistingDirectory(this,"open Folder",".");
    if(fullname.isEmpty()) return;

    QString dir = fullname.right(fullname.length()-fullname.lastIndexOf('/')-1);

    if(!ui->treeWidget->currentIndex().isValid()) return;
    QTreeWidgetItem* parItem = ui->treeWidget->currentItem();
    QTreeWidgetItem* item = new QTreeWidgetItem(itGroupItem);

    QIcon icon(":/images/icon/open.ico");
    item->setIcon(treeColNum::colItem, icon);
    item->setText(treeColNum::colItem, dir);
    item->setText(treeColNum::colItemType, "type:group");
    item->setFlags(Qt::ItemIsSelectable|Qt::ItemIsAutoTristate|Qt::ItemIsEnabled|Qt::ItemIsUserCheckable);
    item->setCheckState(colItem,Qt::Checked);
    parItem->addChild(item);

}

void MainWindow::on_actOpenFile_triggered()
{
    QStringList files = QFileDialog::getOpenFileNames(this,"file or files",".","Images(*.jpg *.png)");
    if (files.isEmpty()) return;

    QTreeWidgetItem* parItem;
    QTreeWidgetItem* item = ui->treeWidget->currentItem();

    if(item->type() == treeItemType::itImageItem)
        parItem = item->parent();
    else
        parItem = item;
    foreach(auto &file, files){
        item = new QTreeWidgetItem(treeItemType::itImageItem);
        QString name = file.right(file.length()-file.lastIndexOf('/')-1);
        QIcon icon(":/images/icon/picture.ico");
        item->setIcon(treeColNum::colItem, icon);
        item->setText(treeColNum::colItem, name);
        item->setText(treeColNum::colItemType, "type:Image");
        item->setFlags(Qt::ItemIsSelectable|Qt::ItemIsAutoTristate|Qt::ItemIsEnabled|Qt::ItemIsUserCheckable);
        item->setCheckState(colItem,Qt::Checked);
        item->setData(treeColNum::colItem,Qt::UserRole,file);
        parItem->addChild(item);
    }

}

void MainWindow::on_treeWidget_currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *previous)
{
    Q_UNUSED(previous);
    if(current == NULL) return;
    int var = current->type();
    switch (var) {
    case treeItemType::itTopItem:
        ui->actOpenFile->setEnabled(true);
        ui->actOpenFolder->setEnabled(true);
        ui->actDel->setEnabled(false);
        break;
    case treeItemType::itGroupItem:
        ui->actOpenFile->setEnabled(true);
        ui->actOpenFolder->setEnabled(true);
        ui->actDel->setEnabled(true);
        break;
    case treeItemType::itImageItem:
        ui->actOpenFile->setEnabled(true);
        ui->actOpenFolder->setEnabled(false);
        ui->actDel->setEnabled(true);
        labFileName.setText(current->data(colItem,Qt::UserRole).toString());
        pixmap.load(current->data(colItem,Qt::UserRole).toString());
        on_actWidth_triggered();
        ui->actWidth->setEnabled(true);
        ui->actHeight->setEnabled(true);
        ui->actZoomIn->setEnabled(true);
        ui->actZoomOut->setEnabled(true);
        ui->actRealSize->setEnabled(true);
        break;
    }
}

void MainWindow::on_actWidth_triggered()
{
    int W = ui->scrollArea->width();
    int realW = pixmap.width();
    pixRatio = (float)W/realW;
    QPixmap pix = pixmap.scaledToWidth(W-30);
    ui->label->setPixmap(pix);

}

void MainWindow::on_actIter_triggered()
{
    for (int i=0; i<ui->treeWidget->topLevelItemCount(); i++) {
        QTreeWidgetItem *item = ui->treeWidget->topLevelItem(i);
        changeItemCaption(item);
    }
}

void MainWindow::changeItemCaption(QTreeWidgetItem *item)
{
    QString str = "x_"+item->text(colItem);
    item->setText(colItem,str);
    for (int i=0; i<item->childCount(); i++) {
        changeItemCaption(item->child(i));
    }
}


void MainWindow::on_actDel_triggered()
{
    QTreeWidgetItem* item = ui->treeWidget->currentItem();
    if (!item->parent()) {
        ui->actDel->setEnabled(false);
        return;
    }
    QTreeWidgetItem* ParItem = item->parent();
    ParItem->removeChild(item);
    delete item;
}

void MainWindow::on_actHeight_triggered()
{
    int H = ui->scrollArea->height();
    int realH = pixmap.height();
    pixRatio = (float)H/realH;
    QPixmap pix = pixmap.scaledToHeight(H-30);
    ui->label->setPixmap(pix);
}

void MainWindow::on_actZoomIn_triggered()
{
    pixRatio *= 1.2;
    int w = pixRatio*pixmap.width();
    int h = pixRatio*pixmap.height();
    QPixmap pix = pixmap.scaled(w,h);
    ui->label->setPixmap(pix);

}

void MainWindow::on_actZoomOut_triggered()
{
    pixRatio *= 0.8;
    int w = pixRatio*pixmap.width();
    int h = pixRatio*pixmap.height();
    QPixmap pix = pixmap.scaled(w,h);
    ui->label->setPixmap(pix);
}

void MainWindow::on_actRealSize_triggered()
{
    ui->label->setPixmap(pixmap);
}

二、效果演示