Qt 5.13 | Qt Purchasing | Qt Purchasing Examples - QtHangman

Qt 5.13.2 Reference Documentation

# Qt Purchasing Examples - QtHangman

QtHangman is an example that demonstrates how to use the Qt Purchasing API with Qt Quick.

QtHangman is a complete mobile application that demonstrates how it is possible to offer in-app products inside a Qt application in a cross-platform manner. In order to test the in-app purchase functionality in the example, you must first register the application and its products in the external store. For an introduction on how to do this, see the guides for Google Play and App Store respectively.

In-app purchasing can be added to a Qt Mobile application by first adding a Store object. In QtHangman the Store object is created by the MainView component that is loaded on application startup.

      Store {
          id: iapStore
      }

QtHangman defines a component for displaying a store for purchasing in-app products made available. These products must be first registered with the store object we created above in MainView. There are two products available, the first being a consumable type.

      Product {
          id: product100Vowels
          store: iapStore
          type: Product.Consumable
          identifier: "org.qtproject.qthangman.100vowels"

          onPurchaseSucceeded: {
              console.log(identifier + " purchase successful");
              applicationData.vowelsAvailable += 100;
              transaction.finalize();
              pageStack.pop();
          }

          onPurchaseFailed: {
              console.log(identifier + " purchase failed");
              console.log("reason: "
                          + transaction.failureReason === Transaction.CanceledByUser ? "Canceled" : transaction.errorString);
              transaction.finalize();
          }
      }

This consumable product provides 100 additional vowels to be used when guessing words in the game. When it is successfully purchased we update the state of the application to include 100 additional vowels. Then we call finalize on the transaction object to confirm to the platform store that the consumable product has been provided.

The second product is a non-consumable type that will unlock vowels permanently in the future. In addition to updating the application state on purchase, we must make sure to provide a way to restore this purchase on other devices used by the end user. In this case we create a signal handler for onPurchaseRestored.

      Product {
          id: productUnlockVowels
          type: Product.Unlockable
          store: iapStore
          identifier: "org.qtproject.qthangman.unlockvowels"

          onPurchaseSucceeded: {
              console.log(identifier + " purchase successful");
              applicationData.vowelsUnlocked = true;
              transaction.finalize();
              pageStack.pop();
          }

          onPurchaseFailed: {
              console.log(identifier + " purchase failed");
              console.log("reason: "
                          + transaction.failureReason === Transaction.CanceledByUser ? "Canceled" : transaction.errorString);
              transaction.finalize();
          }

          onPurchaseRestored: {
              console.log(identifier + "purchase restored");
              applicationData.vowelsUnlocked = true;
              console.log("timestamp: " + transaction.timestamp);
              transaction.finalize();
              pageStack.pop();
          }
      }

In additon to registering the products, we also provide an interface to actually purchase the registered product. QtHangman defines a custom component called StoreItem to display and handle the purchasing interaction.

      Product {
          id: productUnlockVowels
          type: Product.Unlockable
          store: iapStore
          identifier: "org.qtproject.qthangman.unlockvowels"

          onPurchaseSucceeded: {
              console.log(identifier + " purchase successful");
              applicationData.vowelsUnlocked = true;
              transaction.finalize();
              pageStack.pop();
          }

          onPurchaseFailed: {
              console.log(identifier + " purchase failed");
              console.log("reason: "
                          + transaction.failureReason === Transaction.CanceledByUser ? "Canceled" : transaction.errorString);
              transaction.finalize();
          }

          onPurchaseRestored: {
              console.log(identifier + "purchase restored");
              applicationData.vowelsUnlocked = true;
              console.log("timestamp: " + transaction.timestamp);
              transaction.finalize();
              pageStack.pop();
          }
      }

The StoreItem component will display the product data that is queried from the platform's store, and will call the purchase() method on the product when it is clicked by the user.

      Text {
          id: titleText
          text: product.title
          font.bold: true
          anchors.right: priceText.left
          anchors.rightMargin: topLevel.globalMargin
          anchors.top: parent.top
          anchors.topMargin: topLevel.globalMargin
          anchors.left: parent.left
          anchors.leftMargin: topLevel.globalMargin
      }

      Text {
          id: descriptionText
          text: product.description
          anchors.right: priceText.left
          anchors.rightMargin: topLevel.globalMargin
          anchors.left: parent.left
          anchors.leftMargin: topLevel.globalMargin
          anchors.top: titleText.bottom
          anchors.topMargin: topLevel.globalMargin / 2
          wrapMode: Text.WordWrap
      }

      Text {
          id: priceText
          text: product.price
          anchors.right: parent.right
          anchors.rightMargin: topLevel.globalMargin
          anchors.verticalCenter: parent.verticalCenter
      }

      MouseArea {
          anchors.fill: parent
          onClicked: {
              pendingRect.visible = true;
              spinBox.visible = true;
              statusText.text = "Purchasing...";
              storeItem.state = "PURCHASING";
              product.purchase();
          }
          onPressed: {
              storeItem.state = "PRESSED";
          }
          onReleased: {
              storeItem.state = "NORMAL";
          }
      }

Example project @ code.qt.io