在 Xamarin Forms 应用程序中使用 ZXing Mobile

Question

目前正在尝试使用 ZXing Mobile for Xamarin Forms 构建应用程序。

编译的代码没有问题。但是尝试在Android设备上运行时，出现以下错误：

An unhandled exception occcured.

日志显示如下：

[0:] Binding: 'DefaultOverlayTopText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.TopText'
[0:] Binding: 'DefaultOverlayBottomText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.BottomText'
[0:] Binding: 'DefaultOverlayShowFlashButton' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.ShowFlashButton'
[0:] Binding: 'DefaultOverlayTopText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.TopText'
[0:] Binding: 'DefaultOverlayBottomText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.BottomText'
[0:] Binding: 'DefaultOverlayShowFlashButton' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.ShowFlashButton'

这就是我的实现方式：

scanButton.Clicked += async (sender, args) =>
            {
                var options = new MobileBarcodeScanningOptions
                {
                    AutoRotate = false,
                    UseFrontCameraIfAvailable = false,
                    TryHarder = true
                };
                var scanPage = new ZXingScannerPage(options)
                {
                    DefaultOverlayTopText = "Align the barcode within the frame",
                    DefaultOverlayBottomText = string.Empty,
                    DefaultOverlayShowFlashButton = true
                };
                // Navigate to our scanner page
                await Navigation.PushAsync(scanPage);

                scanPage.OnScanResult += (result) =>
                {
                    // Stop scanning
                    scanPage.IsScanning = false;

                    // Pop the page and show the result
                    Device.BeginInvokeOnMainThread(async () =>
                    {
                        await Navigation.PopAsync();
                        await DisplayAlert("Scanned Barcode", result.Text, "OK");
                    });
                };
            };  

还在 Android 的 Main 活动中添加了以下内容，就在 Xamarin 自己的 Init 上方：

ZXing.Net.Mobile.Forms.Android.Platform.Init();

感谢任何帮助。谢谢。

Answer 1

我尝试了您的代码，发现错误与导航更相关。

你正在使用

await Navigation.PushAsync (scanPage);

确保从包含 NavigationPage 的页面调用此方法，否则会崩溃。

要解决此问题，您可以使用

await Navigation.PushModalAsync (scanPage);

相反，它不需要 NavigationPage 并且显示的结果页面将是模态的。使用上面的行，您还需要更改“弹出”视图的方式。

await Navigation.PopModalAsync (true);

注意：

这些消息即使在工作时也会出现在日志中。

[0:] Binding: 'DefaultOverlayTopText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.TopText'
[0:] Binding: 'DefaultOverlayBottomText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.BottomText'
[0:] Binding: 'DefaultOverlayShowFlashButton' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.ShowFlashButton'
[0:] Binding: 'DefaultOverlayTopText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.TopText'
[0:] Binding: 'DefaultOverlayBottomText' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.BottomText'
[0:] Binding: 'DefaultOverlayShowFlashButton' property not found on 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay', target property: 'ZXing.Net.Mobile.Forms.ZXingDefaultOverlay.ShowFlashButton'

希望这会有所帮助。-