qt: rework "receive coins" workflow

src/qt/receivecoinsdialog.h

@@ -0,0 +1,38 @@
+#ifndef RECEIVECOINSDIALOG_H
+#define RECEIVECOINSDIALOG_H
+
+#include <QDialog>
+#include <QVariant>
+
+namespace Ui {
+    class ReceiveCoinsDialog;
+}
+class WalletModel;
+class OptionsModel;
+
+/** Dialog for requesting payment of bitcoins */
+class ReceiveCoinsDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit ReceiveCoinsDialog(QWidget *parent = 0);
+    ~ReceiveCoinsDialog();
+
+    void setModel(WalletModel *model);
+
+public slots:
+    void clear();
+    void reject();
+    void accept();
+
+private:
+    Ui::ReceiveCoinsDialog *ui;
+    WalletModel *model;
+
+private slots:
+    void on_receiveButton_clicked();
+    void updateDisplayUnit();
+};
+
+#endif // RECEIVECOINSDIALOG_H