I last week’s post, Setting status-bar text, I showed how to set the status-bar text in Matlab figures and the main desktop. But Matlab status-bars are Java containers in which we can add GUI controls, not just simple text labels. In this post I will show how to do this for Matlab 7 figures.
Let’s return to the two alternatives I’ve presented in my previous post for setting a Matlab 7 figure status-bar text:
% Alternative #1 (hFig = requested figure's handle) jFrame = get(hFig,'JavaFrame'); jFigPanel = get(jFrame,'FigurePanelContainer'); jRootPane = jFigPanel.getComponent(0).getRootPane; jRootPane = jRootPane.getTopLevelAncestor; statusbarObj = jRootPane.getStatusBar; statusbarObj.setText(statusText); jRootPane.setStatusBarVisible(1); % Alternative #2 jFrame = get(hFig,'JavaFrame'); jRootPane = jFrame.fFigureClient.getWindow; statusbarObj = com.mathworks.mwswing.MJStatusBar; jRootPane.setStatusBar(statusbarObj); statusbarObj.setText(statusText);
The first alternative uses the default status-bar (a com.mathworks.mwswing.MJStatusBar object) which Matlab automatically creates with each figure. This object is created as invisible, so we need to set its text (via its setText method), and then make it visible (via its ancestor’s root-pane’s setStatusBarVisible method – setting the object itself to visible is not enough). The alternative is to replace the default status-bar object with a user-specified container (in this case, we use a new instance of com.mathworks.mwswing.MJStatusBar).
Last week I forgot to mention that only the second alternative works in the general case – it appears that the first alternative often fails because figures are not created with the default statusbar on many platforms/Matlab release (I’m not sure exactly which). My StatusBar utility on the MathWorks File Exchange, which I mentioned in last week’s post, takes care of these nuances, and automatically creates the status bar object if it is missing.
In any case, using these two code snippets as a baseline, we can customize any Java container that we wish. We are not limited to text labels. The default ststusbar container, MJStatusBar, only includes a single JLabel-derived component that stores the text message. We can add other components to this container. For example, let’s add a simple progress-bar:
jFrame = get(hFig,'JavaFrame'); jRootPane = jFrame.fFigureClient.getWindow; statusbarObj = com.mathworks.mwswing.MJStatusBar; % Add a progress-bar to left side of standard MJStatusBar container jProgressBar = javax.swing.JProgressBar; set(jProgressBar, 'Minimum',0, 'Maximum',500, 'Value',234); statusbarObj.add(jProgressBar,'West'); % 'West' => left of text; 'East' => right % Beware: 'East' also works but doesn't resize automatically % Set this container as the figure's status-bar jRootPane.setStatusBar(statusbarObj); % Note: setting setStatusBarVisible(1) is not enough to display the status-bar % - we also need to call setText(), even if only with an empty string '' statusbarObj.setText('testing 123...'); jRootPane.setStatusBarVisible(1);
Status bar with a simple progress-bar
We can of course use the progress-bar and status-bar handles to modify their appearance within our code, for example within some loop. For example:
numIds = length(allIds); set(jProgressBar, 'StringPainted','on', 'Maximum',numIds, 'Value',0); for id = 1 : numIds % Update status bar set(jProgressBar, 'StringPainted','on', 'Value',id); msg = 'Processing %d of %d (%.1f%%)...'; statusbarObj.setText(sprintf(msg,id,numIds,100*id/numIds)); % do something useful... end % for all Ids % Some final status-bar updates... % Hide the progress-bar jProgressBar.setVisible(0); % Hide the corner grip cornerGrip = statusbarObj.getParent.getComponent(0); cornerGrip.setVisible(0); % or: set(cornerGrip,'Visible','off') % Set a red foreground & yellow background to status bar text statusbarObj.setText('All done - congratulations!!!'); statusbarTxt = statusbarObj.getComponent(0); statusbarTxt.setForeground(java.awt.Color.red); set(statusbarTxt,'Background','yellow'); set(statusbarTxt,'Background',[1,1,0]); % an alternative…
Modifying status bar properties in run-time
The progress-bar component was just a simple example of how to present non-intrusive controls/information in the figure status bar. Other controls (buttons, checkboxes etc.) can similarly be added.
Note that the status-bar’s corner-grip (at its far right) is not a sub-component of the statusbarObj object like the label, but rather of its parent JPanel container. This is easily be seen using my FindJObj utility on the MathWorks File Exchange:
Status bar with a simple progress-bar
One final note: The status bar is 20 pixels high across the entire bottom of the figure. It hides everything between pixel heights 0-20, even parts of uicontrols, regardless of who was created first or the relative ComponentZOrder in the frame’s ContentPane:
% Add a "Next phase" button to the right of the text jb = javax.swing.JButton('Next phase >'); jbh = handle(jb,'CallbackProperties'); set(jbh, 'ActionPerformedCallback', @nextPhaseFunction); statusbarObj.add(jb,'East'); %note: we might need jRootPane.setStatusBarVisible(0) % followed by jRootPane.setStatusBarVisible(1) to repaint % Add a simple Matlab uicontrol, obscured by the status-bar hb = uicontrol('string','click me!', 'position',[10,15,70,30]);
Adding controls inside and outside the status-bar
If you have made interesting use of Matlab’s status-bar, please share them in the comments section below.
