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At any point, it is possible to save a form by selecting the Save Form As... option from the File menu. The .ui files saved by Qt Designer contain information about the objects used, and record the details of any signal and slot connections between them. Objects are added to the form by dragging them from the main widget box and dropping them in the desired location on the form. Once there, they can be moved around simply by dragging them, or by using the cursor keys. Pressing the Ctrl key at the same time moves the selected widget pixel by pixel, while using the cursor keys alone make the selected widget snap to the grid when it is moved. Objects can be selected by clicking on them using the left mouse button. You can also use the Tab key to change the selection. The widget box contains objects in a number of different categories, all of which can be simply placed on the form as required. The only objects that require a little more preparation are the Container widgets. These are described in more detail in the Using Containers in Qt Designer chapter. Editing a Form
By default, new forms are opened in widget editing mode. If Qt Designer is in another mode, you can enter widget editing mode by opening the Edit menu and selecting Edit Widgets, or by pressing the F3 key.
![]() | Selecting Objects Objects on the form are selected by clicking on them with the left mouse button. When an object is selected, resize handles are shown at each corner and at the midpoint of each side, indicating that it can be resized. To select additional objects, hold down the Shift key and click on them. If more than one object is selected, the current object will be displayed with resize handles that are colored differently to the others. If you would like to move a widget that is within a layout, holding down Shift and Control while dragging the widget extends the selection to its parent layout. Alternatively, objects can be selected in the Object Inspector. |
Cut | Ctrl+X | Cuts the selected objects to the clipboard. |
Copy | Ctrl+C | Copies the selected objects to the clipboard. |
Paste | Ctrl+V | Pastes the objects in the clipboard onto the form. |
Delete | Delete | Deletes the selected objects. |
Clone object | Ctrl+drag (leftmouse button) | Makes a copy of the selected object or group of objects. |
Preview | Ctrl+R | Shows a preview of the form. |
Widgets are not unique objects; you can make as many copies of them as you need. To quickly duplicate a widget, you can clone it by holding down the Ctrl key and dragging it. This allows widgets to be copied and placed on the form much more quickly than with clipboard operations.
![]() | Drag and Drop Qt Designer makes extensive use of the drag and drop facilities provided by Qt. Widgets can be dragged from the widget box and dropped onto the form. Widgets can also be "cloned" on the form: Holding down Ctrl and dragging the widget creates a copy of the widget that can be dragged to a new position. It is also possible to drop Widgets onto the Object Inspector to ease handling of nested layouts. |
![]() | Editing Properties The property editor uses standard Qt input widgets to manage the properties of objects on the form. Textual properties are shown in line edits, integer properties are displayed in spinboxes, boolean properties are displayed in check boxes, and compound properties such as colors and sizes are presented in drop-down lists of input widgets. Modified properties are indicated by bold labels. To reset, click the arrow button on the right-hand side. Changes in properties are applied to all selected objects that have a matching property. |
![]() | The Object Inspector The Object Inspector displays a hierarchical list of all the objects on the form that is currently being edited. To show the child objects of a container widget or a layout, click the handle next to the object label. Each object on a form can be selected by clicking on the corresponding item in the Object Inspector. Right-clicking opens the form's context menu. These features can be useful if you have many overlapping objects. Since Qt 4.4, double-clicking on the object's name allows you to change the object's name with the in-place editor. |
Once widgets have been inserted into a layout, it is not possible to move and resize them individually because the layout itself controls the geometry of each widget within it, taking account of the hints provided by spacers. Instead, you must either break the layout and adjust each object's geometry manually, or you can influence the widget's geometry by resizing the layout. To break the layout you can press Ctrl+0 or choose Break Layout from the form's context menu, the Form menu or the main toolbar. You can also add and remove spacers from the layout to influence the geometries of the widgets.
![]() | Inserting Objects into a Layout Objects can be inserted into an existing layout by dragging them from their current positions and dropping them at the required location. A blue cursor is displayed in the layout as an object is dragged over it to indicate where the object will be added. |
To apply a layout, you can select your choice of layout from the toolbar
Horizontal and vertical layouts can be combined, and nested to any depth. However, if you need more control over the placement of objects, you should consider using the grid layout.The Grid Layout
Complex form layouts can be created by placed objects in a grid layout. This kind of layout gives the form designer much more freedom to arrange widgets on the form, but can result in a much less flexible layout. However, for some kinds of form layout, a grid arrangement is much more suitable than a nested arrangement of horizontal and vertical layouts.Splitter Layouts
Another common way to manage the layout of objects on a form is to place them in a splitter. These arrange the objects horizontally or vertically in the same way as normal layouts, but also allow the user to adjust the amount of space allocated to each object.
Although QSplitter is a container widget, Qt Designer treats them as layouts that are applied to existing widgets. To place a group of widgets into a splitter, select them as described above then apply the splitter layout by using the appropriate toolbar button, keyboard shortcut, or Lay out context menu entry.The Form Layout
Since Qt 4.4, another layout class has been included - QFormLayout. This class manages widgets in a two-column form; the left column holds labels and the right column holds field widgets such as line edits, spin boxes, etc. The QFormLayout class adheres to various platform look and feel guidelines and supports wrapping for long rows.
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Horizontal | Ctrl+1 | Places the selected objects in a horizontal layout. |
Vertical | Ctrl+2 | Places the selected objects in a vertical layout. |
Grid | Ctrl+5 | Places the selected objects in a grid layout. |
Form | Ctrl+6 | Places the selected objects in a form layout. |
Horizontal splitter | Ctrl+3 | Creates a horizontal splitter and places the selected objects inside it. |
Vertical splitter | Ctrl+4 | Creates a vertical splitter and places the selected objects inside it. |
Adjust size | Ctrl+J | Adjusts the size of the layout to ensure that each child object has sufficient space to display its contents. See QWidget::adjustSize() for more information. |
Since Qt 4.4, it is possible to preview forms with various skins - default skins, skins created with Qt Style Sheets or device skins. This feature simulates the effect of calling QApplication::setStyleSheet() in the application.
To preview your form with skins, open the Edit menu and select Preferences...
You will see the dialog shown below:
![]() | Saving Forms To save a form as an image, choose the Save Image... option. The file will be saved in .png format. Printing Forms To print a form, select the Print... option. |
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