diff options
author | Friedemann Kleint <Friedemann.Kleint@qt.io> | 2022-08-09 10:44:49 +0200 |
---|---|---|
committer | Friedemann Kleint <Friedemann.Kleint@qt.io> | 2022-08-09 18:34:19 +0200 |
commit | c49bf9fe27e0632aa8da393ff007cf4577a1c9cd (patch) | |
tree | 6fa6678dfea898c915faae727e6169caad2f3016 /src/widgets/doc | |
parent | b7812bbbb66d19abf7d3fc3c4f34620a646ce429 (diff) |
Documentation: Fix "Using Model Indexes" in Model View Programming guide to work
The code introduced by 54d5ca0c2766e915c960fa437cee6c20a324c1a7
did not work since the variables parentIndex/numRows
were local to the lambda and the outer code would not wait.
Move the widgets population into the lambda to fix this.
Modernize the remaining code a bit.
Pick-to: 6.4 6.3 6.2
Change-Id: I2a09878987df9edb9ff04f0ac4ad82af1a8b52c8
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Diffstat (limited to 'src/widgets/doc')
-rw-r--r-- | src/widgets/doc/snippets/simplemodel-use/main.cpp | 56 | ||||
-rw-r--r-- | src/widgets/doc/src/model-view-programming.qdoc | 13 |
2 files changed, 40 insertions, 29 deletions
diff --git a/src/widgets/doc/snippets/simplemodel-use/main.cpp b/src/widgets/doc/snippets/simplemodel-use/main.cpp index 62739b1f99..5a3d6ecce0 100644 --- a/src/widgets/doc/snippets/simplemodel-use/main.cpp +++ b/src/widgets/doc/snippets/simplemodel-use/main.cpp @@ -7,55 +7,61 @@ A simple example of how to access items from an existing model. */ -#include <QtGui> +#include <QApplication> +#include <QLabel> +#include <QVBoxLayout> +#include <QWidget> + +#include <QFileSystemModel> +#include <QPalette> + +#include <QDir> +#include <QModelIndex> /*! Create a default directory model and, using the index-based interface to the model and some QLabel widgets, populate the window's layout with the names of objects in the directory. - - Note that we only want to read the filenames in the highest level of the - directory, so we supply a default (invalid) QModelIndex to the model in - order to indicate that we want top-level items. */ int main(int argc, char *argv[]) { QApplication app(argc, argv); - QWidget *window = new QWidget; - QVBoxLayout *layout = new QVBoxLayout(window); - QLabel *title = new QLabel("Some items from the directory model", window); + QWidget window; + auto *layout = new QVBoxLayout(&window); + auto *title = new QLabel("Some items from the directory model", &window); title->setBackgroundRole(QPalette::Base); title->setMargin(8); layout->addWidget(title); //! [0] - QFileSystemModel *model = new QFileSystemModel; - connect(model, &QFileSystemModel::directoryLoaded, [model](const QString &directory) { - QModelIndex parentIndex = model->index(directory); - int numRows = model->rowCount(parentIndex); - }); - model->setRootPath(QDir::currentPath); -//! [0] + auto *model = new QFileSystemModel; + auto onDirectoryLoaded = [model, layout, &window](const QString &directory) { + QModelIndex parentIndex = model->index(directory); + const int numRows = model->rowCount(parentIndex); //! [1] - for (int row = 0; row < numRows; ++row) { - QModelIndex index = model->index(row, 0, parentIndex); + for (int row = 0; row < numRows; ++row) { + QModelIndex index = model->index(row, 0, parentIndex); //! [1] //! [2] - QString text = model->data(index, Qt::DisplayRole).toString(); - // Display the text in a widget. + QString text = model->data(index, Qt::DisplayRole).toString(); //! [2] - - QLabel *label = new QLabel(text, window); - layout->addWidget(label); + // Display the text in a widget. + auto *label = new QLabel(text, &window); + layout->addWidget(label); //! [3] - } + } //! [3] + }; + + QObject::connect(model, &QFileSystemModel::directoryLoaded, onDirectoryLoaded); + model->setRootPath(QDir::currentPath()); +//! [0] - window->setWindowTitle("A simple model example"); - window->show(); + window.setWindowTitle("A simple model example"); + window.show(); return app.exec(); } diff --git a/src/widgets/doc/src/model-view-programming.qdoc b/src/widgets/doc/src/model-view-programming.qdoc index e0febae255..5c09fd0445 100644 --- a/src/widgets/doc/src/model-view-programming.qdoc +++ b/src/widgets/doc/src/model-view-programming.qdoc @@ -449,11 +449,13 @@ \snippet simplemodel-use/main.cpp 0 In this case, we start by setting up a default QFileSystemModel. We connect - it to a lambda, in which we will obtain a parent index using a specific + its signal \c directoryLoaded(QString) to a lambda, in which we will + obtain a parent index for the directory using a specific implementation of \l{QFileSystemModel::}{index()} provided by that model. - In the lambda, we count the number of rows in the model using the - \l{QFileSystemModel::}{rowCount()} function. Finally, we set the root path - of the QFileSystemModel so it starts loading data and triggers the lambda. + + In the lambda, we determine the number of rows in the model using the + \l{QFileSystemModel::}{rowCount()} function. + For simplicity, we are only interested in the items in the first column of the model. We examine each row in turn, obtaining a model index for @@ -474,6 +476,9 @@ \codeline \snippet simplemodel-use/main.cpp 3 + Finally, we set the root path of the QFileSystemModel so it starts + loading data and triggers the lambda. + The above example demonstrates the basic principles used to retrieve data from a model: |