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50
51#include <QtWidgets>
52
53#include "dragwidget.h"
54
55static QLabel *createDragLabel(const QString &text, QWidget *parent)
56{
57 QLabel *label = new QLabel(text, parent);
58 label->setAutoFillBackground(true);
59 label->setFrameShape(QFrame::Panel);
60 label->setFrameShadow(QFrame::Raised);
61 return label;
62}
63
64static QString hotSpotMimeDataKey() { return QStringLiteral("application/x-hotspot"); }
65
66DragWidget::DragWidget(QWidget *parent)
67 : QWidget(parent)
68{
69 QFile dictionaryFile(QStringLiteral(":/dictionary/words.txt"));
70 dictionaryFile.open(flags: QIODevice::ReadOnly);
71 QTextStream inputStream(&dictionaryFile);
72
73 int x = 5;
74 int y = 5;
75
76 while (!inputStream.atEnd()) {
77 QString word;
78 inputStream >> word;
79 if (!word.isEmpty()) {
80 QLabel *wordLabel = createDragLabel(text: word, parent: this);
81 wordLabel->move(ax: x, ay: y);
82 wordLabel->show();
83 wordLabel->setAttribute(Qt::WA_DeleteOnClose);
84 x += wordLabel->width() + 2;
85 if (x >= 245) {
86 x = 5;
87 y += wordLabel->height() + 2;
88 }
89 }
90 }
91
92 setAcceptDrops(true);
93 setMinimumSize(minw: 400, minh: qMax(a: 200, b: y));
94 setWindowTitle(tr(s: "Draggable Text"));
95}
96
97void DragWidget::dragEnterEvent(QDragEnterEvent *event)
98{
99 if (event->mimeData()->hasText()) {
100 if (event->source() == this) {
101 event->setDropAction(Qt::MoveAction);
102 event->accept();
103 } else {
104 event->acceptProposedAction();
105 }
106 } else {
107 event->ignore();
108 }
109}
110
111void DragWidget::dropEvent(QDropEvent *event)
112{
113 if (event->mimeData()->hasText()) {
114 const QMimeData *mime = event->mimeData();
115 QStringList pieces = mime->text().split(sep: QRegularExpression(QStringLiteral("\\s+")),
116 behavior: Qt::SkipEmptyParts);
117 QPoint position = event->pos();
118 QPoint hotSpot;
119
120 QByteArrayList hotSpotPos = mime->data(mimetype: hotSpotMimeDataKey()).split(sep: ' ');
121 if (hotSpotPos.size() == 2) {
122 hotSpot.setX(hotSpotPos.first().toInt());
123 hotSpot.setY(hotSpotPos.last().toInt());
124 }
125
126 for (const QString &piece : pieces) {
127 QLabel *newLabel = createDragLabel(text: piece, parent: this);
128 newLabel->move(position - hotSpot);
129 newLabel->show();
130 newLabel->setAttribute(Qt::WA_DeleteOnClose);
131
132 position += QPoint(newLabel->width(), 0);
133 }
134
135 if (event->source() == this) {
136 event->setDropAction(Qt::MoveAction);
137 event->accept();
138 } else {
139 event->acceptProposedAction();
140 }
141 } else {
142 event->ignore();
143 }
144 for (QWidget *widget : findChildren<QWidget *>()) {
145 if (!widget->isVisible())
146 widget->deleteLater();
147 }
148}
149
150void DragWidget::mousePressEvent(QMouseEvent *event)
151{
152 QLabel *child = qobject_cast<QLabel*>(object: childAt(p: event->pos()));
153 if (!child)
154 return;
155
156 QPoint hotSpot = event->pos() - child->pos();
157
158 QMimeData *mimeData = new QMimeData;
159 mimeData->setText(child->text());
160 mimeData->setData(mimetype: hotSpotMimeDataKey(),
161 data: QByteArray::number(hotSpot.x()) + ' ' + QByteArray::number(hotSpot.y()));
162
163 qreal dpr = window()->windowHandle()->devicePixelRatio();
164 QPixmap pixmap(child->size() * dpr);
165 pixmap.setDevicePixelRatio(dpr);
166 child->render(target: &pixmap);
167
168 QDrag *drag = new QDrag(this);
169 drag->setMimeData(mimeData);
170 drag->setPixmap(pixmap);
171 drag->setHotSpot(hotSpot);
172
173 Qt::DropAction dropAction = drag->exec(supportedActions: Qt::CopyAction | Qt::MoveAction, defaultAction: Qt::CopyAction);
174
175 if (dropAction == Qt::MoveAction)
176 child->close();
177}
178

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