overview

Abstract: This article will introduce the basic concepts, usage methods and application scenarios of Model and View in Qt, and provide an easy-to-understand guide for beginners. We will show how to use Model and View in a specific scenario through a simple code example.

introduce

In Qt, the Model-View architecture is a commonly used design pattern for separating data (Model) from display (View). This design pattern can improve code maintainability and reusability, while simplifying the interaction between data and interface.

2. Basic concepts

Model: Responsible for storing and managing data. In Qt, Model usually inherits from QAbstractItemModel or its subclasses (such as QStandardItemModel).
View: responsible for displaying the data in the Model. In Qt, View can be different types of views such as QListView, QTableView, and QTreeView.
Delegate: Responsible for drawing data in View and handling user input. In Qt, Delegate usually inherits from QStyledItemDelegate or its subclasses.

3. How to use

To use Model and View in Qt, you need to perform the following steps:

Create a Model for storing and managing data.
Create a View to display the data in the Model.
Set the Model as the data source of the View.
(Optional) Create a Delegate for displaying and editing custom data.

4. Code example

Here is a simple code example showing how to use Model and View to display a list of strings in Qt:

#include <QApplication>
#include <QListView>
#include <QStandardItemModel>

int main(int argc, char *argv[]) {
    
    
    QApplication app(argc, argv);

    // 创建Model
    QStandardItemModel model;

    // 添加数据到Model
    QStringList items{
    
    "Item 1", "Item 2", "Item 3"};
    for (const QString &item : items) {
    
    
        QStandardItem *standardItem = new QStandardItem(item);
        model.appendRow(standardItem);
    }

    // 创建View
    QListView listView;

    // 将Model设置为View的数据源
    listView.setModel(&model);

    // 显示View
    listView.show();

    return app.exec();
}

operation result:

5. Application scenarios

The Model-View architecture is suitable for the following scenarios:

Data and display separation: Model-View architecture can be used when you want to separate data storage and display.
Maintainability: Model-View architecture can improve code maintainability because data and display logic are separated.
Reusability: Using the Model-View architecture, you can easily display the same data in different types of views, or reuse the Model in different applications.

6. Expand

Suppose you need to develop a file browser application, you can use QFileSystemModel (Model) and QTreeView (View) to achieve:

#include <QApplication>
#include <QTreeView>
#include <QFileSystemModel>

int main(int argc, char *argv[]) {
    
    
    QApplication app(argc, argv);

    // 创建Model
    QFileSystemModel model;
    model.setRootPath(QDir::currentPath());

    // 创建View
    QTreeView treeView;

    // 将Model设置为View的数据源
    treeView.setModel(&model);

    // 设置View的根节点
    treeView.setRootIndex(model.index(QDir::currentPath()));

    // 显示View
    treeView.show();

    return app.exec();
}

Summarize:

This article provides beginners with an introductory guide to Model and View in Qt, including basic concepts, usage methods and application scenarios. By using the Model-View architecture, you can write more modular and maintainable code. Hope this article can provide a useful reference for your Qt programming.

Getting Started Guide to Model and View in Qt

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