Matlab_GUI学习笔记（一）——对象的基本概念及操作
1. 对象与句柄
以figure为例，在命令行输入：
>>plot([0:10])
>>title('示例')
得到
图像可以看作是桌面的子对象，坐标轴是figure的子对象，函数曲线和“示例”标题是坐标轴的子对象
-
gcf
为当前figure的句柄，类似ans，可以将gcf赋值给变量fig，再通过fig调用当前figure对象的子对象
-
allchild
用doc命令查看allchild文档如下，返回对象的所有子对象的句柄。
调用allchild查看当前figure的所有子对象>>allchild(gcf) ans = 11×1 graphics 数组: Menu (figMenuHelp) Menu (figMenuWindow) Menu (figMenuDesktop) Menu (figMenuTools) Menu (figMenuInsert) Menu (figMenuView) Menu (figMenuEdit) Menu (figMenuFile) Toolbar (FigureToolBar) AnnotationPane Axes (示例) -
get
获得对象的所有属性,调用get函数查看Axes所有属性>>get(ans(11)) ALim: [0 1] ALimMode: 'auto' ActivePositionProperty: 'outerposition' AlphaScale: 'linear' Alphamap: [1×64 double] AmbientLightColor: [1 1 1] BeingDeleted: 'off' Box: 'on' BoxStyle: 'back' BusyAction: 'queue' ButtonDownFcn: '' CLim: [0 1] CLimMode: 'auto' CameraPosition: [6 5 17.3205] CameraPositionMode: 'auto' CameraTarget: [6 5 0] CameraTargetMode: 'auto' CameraUpVector: [0 1 0] CameraUpVectorMode: 'auto' CameraViewAngle: 6.6086 CameraViewAngleMode: 'auto' Children: [1×1 Line] Clipping: 'on' ClippingStyle: '3dbox' Color: [1 1 1] ColorOrder: [7×3 double] ColorOrderIndex: 2 ColorScale: 'linear' Colormap: [64×3 double] CreateFcn: '' CurrentPoint: [2×3 double] DataAspectRatio: [5 5 1] DataAspectRatioMode: 'auto' DeleteFcn: '' FontAngle: 'normal' FontName: 'Helvetica' FontSize: 10 FontSizeMode: 'auto' FontSmoothing: 'on' FontUnits: 'points' FontWeight: 'normal' GridAlpha: 0.1500 GridAlphaMode: 'auto' GridColor: [0.1500 0.1500 0.1500] GridColorMode: 'auto' GridLineStyle: '-' HandleVisibility: 'on' HitTest: 'on' Interactions: [1×1 matlab.graphics.interaction.interface.DefaultAxesInteractionSet] Interruptible: 'on' LabelFontSizeMultiplier: 1.1000 Layer: 'bottom' Legend: [0×0 GraphicsPlaceholder] LineStyleOrder: '-' LineStyleOrderIndex: 1 LineWidth: 0.5000 MinorGridAlpha: 0.2500 MinorGridAlphaMode: 'auto' MinorGridColor: [0.1000 0.1000 0.1000] MinorGridColorMode: 'auto' MinorGridLineStyle: ':' NextPlot: 'replace' OuterPosition: [0 0 1 1] Parent: [1×1 Figure] PickableParts: 'visible' PlotBoxAspectRatio: [1 0.7882 0.7882] PlotBoxAspectRatioMode: 'auto' Position: [0.1300 0.1100 0.7750 0.8150] Projection: 'orthographic' Selected: 'off' SelectionHighlight: 'on' SortMethod: 'childorder' Tag: '' TickDir: 'in' TickDirMode: 'auto' TickLabelInterpreter: 'tex' TickLength: [0.0100 0.0250] TightInset: [0.0367 0.0527 0.0136 0.0544] Title: [1×1 Text] TitleFontSizeMultiplier: 1.1000 TitleFontWeight: 'normal' Toolbar: [1×1 AxesToolbar] Type: 'axes' UIContextMenu: [0×0 GraphicsPlaceholder] Units: 'normalized' UserData: [] View: [0 90] Visible: 'on' XAxis: [1×1 NumericRuler] XAxisLocation: 'bottom' XColor: [0.1500 0.1500 0.1500] XColorMode: 'auto' XDir: 'normal' XGrid: 'off' XLabel: [1×1 Text] XLim: [1 11] XLimMode: 'auto' XMinorGrid: 'off' XMinorTick: 'off' XScale: 'linear' XTick: [1 2 3 4 5 6 7 8 9 10 11] XTickLabel: {11×1 cell} XTickLabelMode: 'auto' XTickLabelRotation: 0 XTickMode: 'auto' YAxis: [1×1 NumericRuler] YAxisLocation: 'left' YColor: [0.1500 0.1500 0.1500] YColorMode: 'auto' YDir: 'normal' YGrid: 'off' YLabel: [1×1 Text] YLim: [0 10] YLimMode: 'auto' YMinorGrid: 'off' YMinorTick: 'off' YScale: 'linear' YTick: [0 1 2 3 4 5 6 7 8 9 10] YTickLabel: {11×1 cell} YTickLabelMode: 'auto' YTickLabelRotation: 0 YTickMode: 'auto' ZAxis: [1×1 NumericRuler] ZColor: [0.1500 0.1500 0.1500] ZColorMode: 'auto' ZDir: 'normal' ZGrid: 'off' ZLabel: [1×1 Text] ZLim: [-1 1] ZLimMode: 'auto' ZMinorGrid: 'off' ZMinorTick: 'off' ZScale: 'linear' ZTick: [-1 0 1] ZTickLabel: '' ZTickLabelMode: 'auto' ZTickLabelRotation: 0 ZTickMode: 'auto' -
set
对一个对象的属性进行操作,调用set函数改变坐标轴Axes的位置（position）属性，由上面属性查看可以看到position属性初始值为Position: [0.1300 0.1100 0.7750 0.8150]，下面更改其高度与宽度>>set(ans(11), 'position', [0.1300 0.1100 0.5 0.5])更改后的figure变成下面这个样子
-
findobj
找到所需要的对象的句柄。比如要找到上面的标题文本“示例”的句柄，可以这样写findobj(allchild(gca), 'type', 'Text')视频教程上可以得到多个静态文本对象，但我使用的是matlab2019a可能因为版本的原因，gca为’line’属性，gcf为’Axes’属性
>> allchild(gca) ans = Line - 属性: Color: [0 0.4470 0.7410] LineStyle: '-' LineWidth: 0.5000 Marker: 'none' MarkerSize: 6 MarkerFaceColor: 'none' XData: [1 2 3 4 5 6 7 8 9 10 11] YData: [0 1 2 3 4 5 6 7 8 9 10] ZData: [1×0 double] 显示 所有属性 AlignVertexCenters: 'off' Annotation: [1×1 matlab.graphics.eventdata.Annotation] BeingDeleted: 'off' BusyAction: 'queue' ButtonDownFcn: '' Children: [0×0 GraphicsPlaceholder] Clipping: 'on' Color: [0 0.4470 0.7410] CreateFcn: '' DataTipTemplate: [1×1 matlab.graphics.datatip.DataTipTemplate] DeleteFcn: '' DisplayName: '' HandleVisibility: 'on' HitTest: 'on' Interruptible: 'on' LineJoin: 'round' LineStyle: '-' LineWidth: 0.5000 Marker: 'none' MarkerEdgeColor: 'auto' MarkerFaceColor: 'none' MarkerIndices: [1 2 3 4 5 6 7 8 9 10 11] MarkerSize: 6 Parent: [1×1 Axes] PickableParts: 'visible' Selected: 'off' SelectionHighlight: 'on' Tag: '' Type: 'line' UIContextMenu: [0×0 GraphicsPlaceholder] UserData: [] Visible: 'on' XData: [1 2 3 4 5 6 7 8 9 10 11] XDataMode: 'auto' XDataSource: '' YData: [0 1 2 3 4 5 6 7 8 9 10] YDataSource: '' ZData: [1×0 double] ZDataSource: ''通过
findobj(allchild(gca), 'String', '示例')，findobj(allchild(gcf), 'type', 'text')，findobj('type', 'text')，findobj('String', '示例')，findobj(gca,'Type','text','String','示例')均未找到title“示例”对象的句柄。如果知道其句柄，可以通过set函数设置静态文本的属性，比如字体，颜色，字号等。
2. 对象操作实例
通过直接调用函数并设置对象属性，创建一个简单的颜色动态函数曲线图
%界面
h = figure('Units','normalized',... %单位归一化，使在0-1之间
'Position', [0.2,0.2,0.5,0.5],...
'Menu', 'none');
ha = axes('parent', h, 'Units', 'normalized',... %坐标轴的父对象为图像figure
'position',[0.1,0.1,0.8,0.8]);
hl = line('parent', ha, 'XData', [0:0.01:6],... %函数曲线的父对象为坐标轴axes
'YData', sin([0:0.01:6]), 'Color', 'r');
cstring = 'gbkay';
for k = 1:5
set(hl, 'Color', cstring(k));
pause(3);
end
使用get，set，findobj，doc等函数读懂并运行这段代码。