Dynamically create multiple layouts
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repeated in a certain number of times based on the user's input
the number of layouts is not fixed ?
@mpergand Max is 15, I created the 15 spaces in the from ui. The number created on at runtime depends on the user input
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Hi,
Since you have a dynamic number of objects, you should use a QVector to hold the exact number of them.
That will simplify your code and memory handling.
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@mpergand Max is 15, I created the 15 spaces in the from ui. The number created on at runtime depends on the user input
@SamuelAdesola
As @SGaist said use QVector:LayoutWidgets layoutArray[LayoutCount];
QVector<LayoutWidgets> layoutArray;then first create a LayoutWidgets instance in the loop:
for(int i=0; i<LayoutCount; i++)
{
layoutArray<<LayoutWidgets;
....Max is 15, I created the 15 spaces in the from ui
Why not create this layouts in code as well?
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@SamuelAdesola
One possibility:const int LayoutCount=7; struct LayoutWidgets { QHBoxLayout* layout; QLabel* CourseCodeLabel; QLineEdit* CourseCodeLineEdit; QLabel* CourseGradeLabel; QComboBox* CourseGradeComboBox; }; LayoutWidgets layoutArray[LayoutCount]; ... // populate layoutArray for(int i=0; i<LayoutCount; i++) { QHBoxLayout* layout=this->findChild<QHBoxLayout*>(QString("horizontalLayout_%1").arg(i+1)); if(layout==nullptr) { // not found continue; } layoutArray[i].layout=layout; layoutArray[i].CourseCodeLabel=new QLabel; layoutArray[i].CourseCodeLineEdit=new QLineEdit; layoutArray[i].CourseGradeLabel=new QLabel; layoutArray[i].CourseGradeComboBox=new QComboBox; // populate QLayout layout->addWidget(layoutArray[i].CourseCodeLabel); layout->addWidget(layoutArray[i].CourseCodeLineEdit); layout->addWidget(layoutArray[i].CourseGradeLabel); layout->addWidget(layoutArray[i].CourseGradeComboBox); }Of course not tested !
@mpergand
I successfully implemented this but came across a problem along the way, i have tried solving it but i am still not getting it.After dynamically creating the objects using QVector, I wanted to access the element of the object using another funtion when a button is clicked but the program keeps crashing.
How can i access these elements in another function?
I want to be able to do something like
qDebug() << layoutArray[1].CourseCodeLabel->text(); -
@mpergand
I successfully implemented this but came across a problem along the way, i have tried solving it but i am still not getting it.After dynamically creating the objects using QVector, I wanted to access the element of the object using another funtion when a button is clicked but the program keeps crashing.
How can i access these elements in another function?
I want to be able to do something like
qDebug() << layoutArray[1].CourseCodeLabel->text();@SamuelAdesola
Use the debugger and show us the stack trace. -
I will implement this and get back to you.
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@mpergand
I successfully implemented this but came across a problem along the way, i have tried solving it but i am still not getting it.After dynamically creating the objects using QVector, I wanted to access the element of the object using another funtion when a button is clicked but the program keeps crashing.
How can i access these elements in another function?
I want to be able to do something like
qDebug() << layoutArray[1].CourseCodeLabel->text();@SamuelAdesola
If you have code likelayoutArray[1].CourseCodeLabel->text()which crashes you will doubtless find thatlayoutArray[1]does not exist orlayoutArray[1]->CourseCodeLabelis null/not valid. Which a stack trace should indeed reveal. -
I will implement this and get back to you.
@jonezzpeterr
Ok, I'll be looking forward to it -
@SamuelAdesola
If you have code likelayoutArray[1].CourseCodeLabel->text()which crashes you will doubtless find thatlayoutArray[1]does not exist orlayoutArray[1]->CourseCodeLabelis null/not valid. Which a stack trace should indeed reveal.@JonB
Can I make layoutArray a global variable so if I assign it in a function, I can access it in another function. One function is to show the user the forms layouts and another is to use the inputed data to do some calculations. I should have put them in same function but the calculation aspect automatically use the empty fields when a button is press. There are 2 buttons, one to show the user the fields and the other to make use of the inputed data for some calculations. -
@JonB
Can I make layoutArray a global variable so if I assign it in a function, I can access it in another function. One function is to show the user the forms layouts and another is to use the inputed data to do some calculations. I should have put them in same function but the calculation aspect automatically use the empty fields when a button is press. There are 2 buttons, one to show the user the fields and the other to make use of the inputed data for some calculations.@SamuelAdesola
Make it a class member variable, rather than global, and you can access it in any class method. The fact that it is array is not relevant. And btw if it's a plain C array better use aQVector, say. -
@SamuelAdesola
Make it a class member variable, rather than global, and you can access it in any class method. The fact that it is array is not relevant. And btw if it's a plain C array better use aQVector, say.@JonB @mpergand @jonezzpeterr @SGaist
Thanks very much for the support, I think i have achieve quite a lot of those giving tough time.
As @SGaist said I am using QVector and as @JonB said i declare it as a class member variable
QVector<LayoutWidgets> layoutArray;Because the size will be set at run time base on user input, i resize the vector in a function
layoutArray.resize(LayoutCount);and i am able to make calls to my class setters to set the values in layoutArray and use another getter function to access the set values
