使用qml添加条件的类

Question

I have an item and I want to add a class into it, this one depend on a variable

import "class1"
import "class2"

Item { id: myID
property variant myVar: 0;

anchors.fill: parent;

function update() { 


     switch(myID.myVar)
     {
     case 0:        
        class1 {
             anchors.fill: parent;
        }       
        break;

    case 1:
        class2 {
             anchors.fill: parent;
        }
        break;
    }
}

}

Actually this is a wrong code, any way to do that ?

Thank you.

Answer 1

QML and JavaScript intermesh, but what you're trying to use is QML class instantiation syntax in JavaScript context - it won't ever work that way. Once a QML file is loaded, all the class instances defined therein are already instantiated.

You need to define two components, and use a loader to dynamically create one of them. So, something like the below. I haven't tested it, but it should steer you in the right direction, I hope.

import "class1"
import "class2"

Item {
  id: myItem
  property variant myVar: 0;
  anchors.fill: parent;

  Component { 
    id: compClass1
    class1 {
      anchors.fill: myItem;
    }
  }       
  Component { 
    id: compClass12    
    class2 {
      anchors.fill: myItem;
    }
  } 
  Loader { id: myLoader }      

  function update() { 
    switch(myID.myVar) {
    case 0:
      myLoader.sourceComponent = compClass1;
      break;
    }
    case 1:
      myLoader.sourceComponent = compClass2;
      break;
    }
  }
}