[SailfishDevel] ComboBox issue (initialization)

[Andrey Kozhevnikov]

Hello. You need to set currentIndex after your model data initialized, 
not object. You can initialize at onCountChanged or make special signal 
from signal and listen it.

09.09.2014 19:07, François K. пишет:
> Hi :)
>
> I have a ComboBox issue !
>
> The ComboBox I want to use is made of dynamic items. I build it with a ListModel and a Repeater as follow :
>
> ComboBox {
>      id: project
>
>      label: qsTr("Project")
>      menu: ContextMenu {
>          MenuItem { text: qsTr("Not set") }
>
>          Repeater {
>              model: ProjectsModel { id: projects }
>              delegate: MenuItem { text: model.value }
>          }
>      }
> }
>
> It works pretty well (yay QML !).
>
> Now I would like to initialize the ComboBox value. I tried several things (see after) and none of them worked.
> I hope you guys can give me some help/tip :)
>
>
>
> 1. First I tried to set its value directly. It doesn't really work well :
>
>    * The text that appears is the good one - OK
>    * When I open the ComboBox to chose another value, the highlighted item is not the good one (which means that the ComboBox doesn't compute currentIndex and currentItem automagically when one set the ComboBox value) ;
>    * Moreover, when I select another item in the menu, the currentIndex and currentItem are changed as expected, but the value of the ComboBox doesn't change.
>
> Here is the code that highlights the problem :
>
> ComboBox {
>      id: project
>
>      label: qsTr("Project")
>      menu: ContextMenu {
>          MenuItem { text: qsTr("Not set") }
>      
>          Repeater {
>              model: ProjectsModel { id: projects }
>              delegate: MenuItem { text: model.value }
>          }
>      }
>
>      value: "Some Value"
>
>      onCurrentIndexChanged: {
>          console.log("currentIndex just changed to : ", currentIndex);
>      }
>
>      onCurrentItemChanged: {
>          console.log("currentItem just changed to : ", currentItem.text);
>      }
>
>      onValueChanged: {
>          console.log("value just changed to : ", value);
>      }
> }
>
> And the output :
>
> [D] onValueChanged:159 - value just changed to : Foo
> [...]
> [D] onCurrentItemChanged:155 - currentItem just changed to : Bar
> [D] onCurrentIndexChanged:151 - currentIndex just changed to : 2
>
> What I expected to see :
>
> [D] onValueChanged:159 - value just changed to : Foo
> [...]
> [D] onCurrentItemChanged:155 - currentItem just changed to : Bar
> [D] onCurrentIndexChanged:151 - currentIndex just changed to : 2
> [D] onValueChanged:159 - value just changed to : Bar
>
>
>
> 2. Then I tried to set currentIndex. There, for some reason that I don't explain, it seems that the ComboBox always "resets" :
>
> Component {
>
>      // Some other stuff here
>
>      ComboBox {
>          id: project
>
>          label: qsTr("Project")
>          menu: ContextMenu {
>              MenuItem { text: qsTr("Not set") }
>
>              Repeater {
>                  model: ProjectsModel { id: projects }
>                  delegate: MenuItem { text: model.value }
>              }
>          }
>
>          onCurrentIndexChanged: {
>              console.log("currentIndex just changed to : ", currentIndex);
>          }
>
>          onCurrentItemChanged: {
>              console.log("currentItem just changed to : ", currentItem.text);
>          }
>
>          onValueChanged: {
>              console.log("value just changed to : ", value);
>          }
>      }
>
>      Component.onCompleted: {
>          // Here I get the task object from the database.
>          var task = Storage.getTask(id);
>
>          if(task !== null)
>          {
>              for(var i=0 ; i<projects.count ; i++)
>              {
>                  if(task.project === projects.get(i).value)
>                  {
>                      project.currentIndex = i + 1; // We have to +1 because of the <Not set> MenuItem.
>                      break;
>                  }
>              }
>          }
>      }
> }
>
> And the output :
>
> [D] onCurrentIndexChanged:151 - currentIndex just changed to : 2
> [D] onCurrentIndexChanged:151 - currentIndex just changed to : 0
>
>
> I also noticed that, in this case, it reverts to 0 because I have a hardcoded MenuItem at index 0.
> If I remove the first hardcoded "Not set" MenuItem, ComboBox.currentIndex reverts to -1.
> If I have only hardcoded MenuItems, it works as expected.
>
>
>
> By the way, I think it could be great for the ComboBox to behave like HTML’s <select> :
> MenuItem could have a text and a value property. Setting a ComboBox value would automatically update currentItem and currentIndex.
> Something like this :
>
> ComboBox {
>      menu: ContextMenu {
>          MenuItem {
>              text: qsTr("Some item")
>              value: "some_item"
>          }
>          MenuItem {
>              text: qsTr("Another item")
>              value: "another_item"
>          }
>      }
>
>      Component.onCompleted: {
>          value = "another_item"; // This would highlight the second item, set currentIndex to 1 and currentItem accordingly.
>      }
> }
>
> Of course, one could still set currentIndex or currentItem, and it would update everything accordingly.
>
> I'd be glad to work on this if you agree :)
>
>
> Thanks for your attention.
>
> My best wishes,
>