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50
51#include "draglabel.h"
52#include "dragwidget.h"
53
54#include <QtWidgets>
55
56static inline QString fridgetMagnetsMimeType() { return QStringLiteral("application/x-fridgemagnet"); }
57
58//! [0]
59DragWidget::DragWidget(QWidget *parent)
60 : QWidget(parent)
61{
62 QFile dictionaryFile(QStringLiteral(":/dictionary/words.txt"));
63 dictionaryFile.open(flags: QFile::ReadOnly);
64 QTextStream inputStream(&dictionaryFile);
65//! [0]
66
67//! [1]
68 int x = 5;
69 int y = 5;
70
71 while (!inputStream.atEnd()) {
72 QString word;
73 inputStream >> word;
74 if (!word.isEmpty()) {
75 DragLabel *wordLabel = new DragLabel(word, this);
76 wordLabel->move(ax: x, ay: y);
77 wordLabel->show();
78 wordLabel->setAttribute(Qt::WA_DeleteOnClose);
79 x += wordLabel->width() + 2;
80 if (x >= 245) {
81 x = 5;
82 y += wordLabel->height() + 2;
83 }
84 }
85 }
86//! [1]
87
88//! [2]
89 QPalette newPalette = palette();
90 newPalette.setColor(acr: QPalette::Window, acolor: Qt::white);
91 setPalette(newPalette);
92
93 setMinimumSize(minw: 400, minh: qMax(a: 200, b: y));
94 setWindowTitle(tr(s: "Fridge Magnets"));
95//! [2] //! [3]
96 setAcceptDrops(true);
97}
98//! [3]
99
100//! [4]
101void DragWidget::dragEnterEvent(QDragEnterEvent *event)
102{
103//! [4] //! [5]
104 if (event->mimeData()->hasFormat(mimetype: fridgetMagnetsMimeType())) {
105 if (children().contains(t: event->source())) {
106 event->setDropAction(Qt::MoveAction);
107 event->accept();
108 } else {
109 event->acceptProposedAction();
110//! [5] //! [6]
111 }
112//! [6] //! [7]
113 } else if (event->mimeData()->hasText()) {
114 event->acceptProposedAction();
115 } else {
116 event->ignore();
117 }
118}
119//! [7]
120
121//! [8]
122void DragWidget::dragMoveEvent(QDragMoveEvent *event)
123{
124 if (event->mimeData()->hasFormat(mimetype: fridgetMagnetsMimeType())) {
125 if (children().contains(t: event->source())) {
126 event->setDropAction(Qt::MoveAction);
127 event->accept();
128 } else {
129 event->acceptProposedAction();
130 }
131 } else if (event->mimeData()->hasText()) {
132 event->acceptProposedAction();
133 } else {
134 event->ignore();
135 }
136}
137//! [8]
138
139//! [9]
140void DragWidget::dropEvent(QDropEvent *event)
141{
142 if (event->mimeData()->hasFormat(mimetype: fridgetMagnetsMimeType())) {
143 const QMimeData *mime = event->mimeData();
144//! [9] //! [10]
145 QByteArray itemData = mime->data(mimetype: fridgetMagnetsMimeType());
146 QDataStream dataStream(&itemData, QIODevice::ReadOnly);
147
148 QString text;
149 QPoint offset;
150 dataStream >> text >> offset;
151//! [10]
152//! [11]
153 DragLabel *newLabel = new DragLabel(text, this);
154 newLabel->move(event->pos() - offset);
155 newLabel->show();
156 newLabel->setAttribute(Qt::WA_DeleteOnClose);
157
158 if (event->source() == this) {
159 event->setDropAction(Qt::MoveAction);
160 event->accept();
161 } else {
162 event->acceptProposedAction();
163 }
164//! [11] //! [12]
165 } else if (event->mimeData()->hasText()) {
166 QStringList pieces = event->mimeData()->text().split(
167 sep: QRegularExpression(QStringLiteral("\\s+")), behavior: Qt::SkipEmptyParts);
168 QPoint position = event->pos();
169
170 for (const QString &piece : pieces) {
171 DragLabel *newLabel = new DragLabel(piece, this);
172 newLabel->move(position);
173 newLabel->show();
174 newLabel->setAttribute(Qt::WA_DeleteOnClose);
175
176 position += QPoint(newLabel->width(), 0);
177 }
178
179 event->acceptProposedAction();
180 } else {
181 event->ignore();
182 }
183}
184//! [12]
185
186//! [13]
187void DragWidget::mousePressEvent(QMouseEvent *event)
188{
189//! [13]
190//! [14]
191 DragLabel *child = static_cast<DragLabel*>(childAt(p: event->pos()));
192 if (!child)
193 return;
194
195 QPoint hotSpot = event->pos() - child->pos();
196
197 QByteArray itemData;
198 QDataStream dataStream(&itemData, QIODevice::WriteOnly);
199 dataStream << child->labelText() << QPoint(hotSpot);
200//! [14]
201
202//! [15]
203 QMimeData *mimeData = new QMimeData;
204 mimeData->setData(mimetype: fridgetMagnetsMimeType(), data: itemData);
205 mimeData->setText(child->labelText());
206//! [15]
207
208//! [16]
209 QDrag *drag = new QDrag(this);
210 drag->setMimeData(mimeData);
211 drag->setPixmap(child->pixmap(Qt::ReturnByValue));
212 drag->setHotSpot(hotSpot);
213
214 child->hide();
215//! [16]
216
217//! [17]
218 if (drag->exec(supportedActions: Qt::MoveAction | Qt::CopyAction, defaultAction: Qt::CopyAction) == Qt::MoveAction)
219 child->close();
220 else
221 child->show();
222}
223//! [17]
224

source code of qtbase/examples/widgets/draganddrop/fridgemagnets/dragwidget.cpp