初學qml，需要實現單擊鼠標，使所點擊的Rectangle（有多個Rectangle）獲得焦點，並改變顏色。
這個實現起來呢並不麻煩，在每個Rectangle中加入MouseArea實現即可，但是我並不想這樣做，想只用一個MouseArea，這就需要判斷點擊的是哪個，於是我想通過鼠標點擊的座標判斷，搜索無果但是找到了一個函數childAt()，於是乎依據此函數小小的實現了下。
childAt用法：
Returns the visible child item at point (x, y), which is in this item's coordinate system, ornull if there is no such item.
其它：
鼠標當前座標 mouseX , mouseY
代碼如下：
Rectangle {
width: 200; height: 200; color: "black"
Grid {
id: cl
columns: 2
spacing: 6
Rectangle {
id: r1
width: 80; height: 80
color: "yellow"
opacity: focus ? 1 : 0.5
focus: true
//KeyNavigation.right: r2
//KeyNavigation.down: r3
}
Rectangle {
id: r2
width: 80; height: 80
color: "lightblue"
opacity: focus ? 1 : 0.5
//KeyNavigation.right: r3
//KeyNavigation.down: r4
}
Rectangle {
id: r3
width: 80; height: 80
color: "green"
opacity: focus ? 1 : 0.5
//KeyNavigation.right: r4
//KeyNavigation.up: r1
}
Rectangle {
id: r4
width: 80; height: 80
color: "purple"
opacity: focus ? 1 : 0.5
//KeyNavigation.right: r1
//KeyNavigation.up: r2
}
}
MouseArea {
anchors.fill: parent
onClicked: {
if(cl.childAt(mouseX , mouseY))
cl.childAt(mouseX , mouseY).focus = true;
//console.log(mouseX,mouseY);
//console.log(cl.childAt(mouseX , mouseY));
}
}
}