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NativeView

NativeView allows to instantiate and display platform-specific views and widgets. More...

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Properties

• androidBinding : Component
• binding : NativeViewBinding
• iosBinding : Component
• updatesPerSecond : int

Detailed Description

This item allows to display widgets from native Android & iOS frameworks using QML code. It can display any native view object directly inside the QML scene graph. For example, you can add a native Button, ImageView or WebView to your Felgo app. This screenshot shows an example app with these three components on Android and iOS:

Displaying native views is only supported on Android and iOS. On desktop platforms, NativeView displays a dummy view that draws nothing.

 QQuickWindow::setGraphicsApi(QSGRendererInterface::OpenGLRhi);

NativeView allows specifying which view to instantiate on Android and iOS. On Android, it can display any instance of android.view.View. On iOS, it can display any instance of UIView. You can specify which view class to instantiate on each platform. Use the androidBinding and iosBinding properties for this.

You can then access the native view object as NativeObject instance. Use the property NativeViewBinding::view for this.

The view behaves exactly like it would in a native app. However, it is still rendered inside the QML scene graph. The native view's size gets set to the size of the QML item.

Use Cases

Most apps do not need to display native views. Instead, they can use the Felgo Apps Components. Certain advanced use cases might require to directly use native views and widgets.

Display native Android & iOS widgets

NativeView is useful if you want to add native functionality to your Felgo app. For example, you can display a native Button, ImageView or WebView. This allows you to use the full power of QML, like animations and graphical effects, with any native view. See Usage Example for a full example of a QML component that shows a native Button.

Integrate third-party SDKs

You can also use this item to integrate native third-party SDKs with your Felgo app. These SDKs often offer widgets to display on Android and iOS. You can display those widgets directly within your QML scene with NativeView.

Usage Example

The following code shows an example implementation of a native button. It instantiates a native button on Android (android.widget.Button) and on iOS (UIButton). You could then use this QML type just like AppButton within your QML scene.

The platform-specifics are defined with NativeViewBinding. The properties androidBinding and iosBinding each contain a component that defines behavior on the respective platforms.

The property viewClassName defines which view class to instantiate. Alternatively, you can customize the view initialization with onCreateView.

The view instance gets initialized via view in onViewCreated().

The example QML type has a text property. It sets the native button's text to this value on creation and when its value changes. On Android it sets the text with TextView.setText() and On iOS with setTitle:forState:.

It adds a JavaScript function as listener to a button click event. On Android this works by calling setOnClickListener(). On iOS the function is added using addTarget:action:forControlEvents:. This function then emits a QML signal that application code can connect to.

 import Felgo
 import QtQuick

 App {
   NativeView {
     id: dynamicNativeButton
     width: dp(170)
     height: dp(48)
     anchors.centerIn: parent

     property string text: qsTr("Native Button")
     signal clicked

     onTextChanged: if(binding) binding.updateText()

     androidBinding: NativeViewBinding {
       viewClassName: "android.widget.Button"

       onViewCreated: {
         updateText()

         // add OnClickListener:
         view.callMethod("setOnClickListener", function(v) {
           // call QML signal:
           dynamicNativeButton.clicked()
         })
       }

       function updateText() {
         view.callMethod("setText", dynamicNativeButton.text, NativeObject.UiThread)
       }
     }

     iosBinding: NativeViewBinding {
       viewClassName: "UIButton"

       // imports
       readonly property NativeClass _UIColor: NativeObjectUtils.getClass("UIColor")

       // delegates - store strong reference here:
       readonly property NativeObject clickAction: NativeObjectUtils.wrap({
         // note: selector name contains colon ':', so this key must also contain it
         "onClick:forEvent:": function(view, event) {
           dynamicNativeButton.clicked()
         }
       })

       onViewCreated: {
         updateText()

         // configure button visuals:
         view.setProperty("backgroundColor", _UIColor.getProperty("grayColor"))
         view.callMethod("setTitleColor:forState:", [_UIColor.getProperty("blackColor"), 0])
         view.callMethod("setTitleColor:forState:", [_UIColor.getProperty("whiteColor"), 1])

         // add touchUpInside target:
         var _UIControlEventTouchUpInside = 1 << 6
         view.callMethod("addTarget:action:forControlEvents:", [clickAction, "onClick:forEvent:", _UIControlEventTouchUpInside])
         // target selectors can either be "doSomething", "doSomething:(id)sender" or "doSomething:(id)sender forEvent:(UIEvent*)event"
         // selector name must be exactly the same as the function's key in the JS object
       }

       function updateText() {
         view.callMethod("setTitle:forState:", [dynamicNativeButton.text, 0])
       }
     }
   }
 }

Available QML Items

Property Documentation

 import Felgo
 import QtQuick

 App {
   NativeView {
     id: dynamicNativeButton
     width: dp(170)
     height: dp(48)
     anchors.centerIn: parent

     property string text: qsTr("Native Button")
     signal clicked

     onTextChanged: if(binding) binding.updateText()

     androidBinding: NativeViewBinding {
       viewClassName: "android.widget.Button"

       onViewCreated: {
         updateText()

         // add OnClickListener:
         view.callMethod("setOnClickListener", function(v) {
           // call QML signal:
           dynamicNativeButton.clicked()
         })
       }

       function updateText() {
         view.callMethod("setText", dynamicNativeButton.text, NativeObject.UiThread)
       }
     }

     iosBinding: NativeViewBinding {} // TODO
   }
 }

 import Felgo
 import QtQuick

 App {
   NativeView {
     id: dynamicNativeButton
     width: dp(170)
     height: dp(48)
     anchors.centerIn: parent

     property string text: qsTr("Native Button")
     signal clicked

     onTextChanged: if(binding) binding.updateText()

     androidBinding: NativeViewBinding {} // TODO

     iosBinding: NativeViewBinding {
       viewClassName: "UIButton"

       readonly property NativeObject _UIColor: NativeObjectUtils.getClass("UIColor")

       onViewCreated: {
         updateText()

         // configure button visuals:
         view.setProperty("backgroundColor", _UIColor.getProperty("grayColor"))
         view.callMethod("setTitleColor:forState:", [_UIColor.getProperty("blackColor"), 0])
         view.callMethod("setTitleColor:forState:", [_UIColor.getProperty("whiteColor"), 1])

         // add touchUpInside target:
         var _UIControlEventTouchUpInside = 1 << 6
         view.callMethod("addTarget:action:forControlEvents:", [{
           // note: selector name contains colon ':', so this key must also contain it
           "onClick:forEvent:": function(view, event) {
             dynamicNativeButton.clicked()
           }
         }, "onClick:forEvent:", _UIControlEventTouchUpInside])
         // target selectors can either be "doSomething", "doSomething:(id)sender" or "doSomething:(id)sender forEvent:(UIEvent*)event"
         // selector name must be exactly the same as the function's key in the JS object
       }

       function updateText() {
         view.callMethod("setTitle:forState:", [dynamicNativeButton.text, 0])
       }
     }
   }
 }