windows-phone-8 - 交叉淡入淡出页面过渡 Windows phone 8 工具包

Question

我正在使用 Windows Phone 8 工具包和 Microsoft.Phone.Controls 提供的 TransitionService 实现 NavigationTransition。我期待页面在过渡期间交叉淡入淡出，但默认情况下它们不会交叉淡入淡出。

例如，如果我要使用淡出过渡返回上一页，则原始页面会在目标页面出现之前淡入完全不透明，从而产生“弹出”效果。

我希望有人可以提供指导以实现这种效果。

Answer 1

我最终使用了一些轻微的屏幕截图和远背景平面来使电话页面看起来“交叉淡入淡出” - 这里有编辑掉的商业细节：

public class FormPage : PhoneApplicationPage {
    public FormPage() {
        InitializeComponent();
        PrepareAnimationIn(FormApp.frameTransition);
    }

    void PrepareAnimationIn(string pageAnimation) {
        AnimatedPageFactory.SetNavigationInTransition(pageAnimation, this);
    }

    public void PrepareAnimationOut(string pageAnimation) {
        AnimatedPageFactory.SetNavigationOutTransition(pageAnimation, this);
    }

    void StoreScreenShot(string name, WriteableBitmap bitmap) {
        using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) {
            string path = Path.Combine(screenshotDir, name + screenFileType);
            store.CreateDirectory(screenshotDir);
            using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(path, FileMode.Create, store)) {
                using (BinaryWriter writer = new BinaryWriter(stream)) {
                    int count = bitmap.Pixels.Length * sizeof(int);
                    byte[] pixels = new byte[count];
                    Buffer.BlockCopy(bitmap.Pixels, 0, pixels, 0, count);
                    writer.Write(pixels, 0, pixels.Length);
                }
            }
        }
    }

    WriteableBitmap FetchScreenShot(string name) {
        WriteableBitmap bitmap = new WriteableBitmap((int)this.ActualWidth, (int)this.ActualHeight);

        using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) {
            string path = Path.Combine(screenshotDir, name + screenFileType);
            if (store.FileExists(path)) {

                using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(path, FileMode.Open, store)) {
                    using (BinaryReader reader = new BinaryReader(stream)) {
                        int count = bitmap.Pixels.Length * sizeof(int);
                        byte[] pixels = new byte[count];
                        reader.Read(pixels, 0, count);
                        Buffer.BlockCopy(pixels, 0, bitmap.Pixels, 0, count);
                    }
                }

                store.DeleteFile(path);
            }
        }
        return bitmap;
    }

    WriteableBitmap ScreenShot() {
        WriteableBitmap bmpCurrentScreenImage = new WriteableBitmap((int)this.ActualWidth, (int)this.ActualHeight);
        bmpCurrentScreenImage.Render(_canvas, new MatrixTransform());
        bmpCurrentScreenImage.Invalidate();
        return bmpCurrentScreenImage;
    }

    ImageBrush ImageBrushFromBitmap(WriteableBitmap bitmap) {
        return new ImageBrush { ImageSource = bitmap };
    }

    static Stack<string> formImages = new Stack<string>();
    static string screenFileType = ".frmscn";
    static string screenshotDir = "frmscrn";

    protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) {

        var app = Application.Current as App;

        if (e.NavigationMode == NavigationMode.New &&
            e.Uri.ToString().Contains("FormPage.xaml")) {

            WriteableBitmap screenShot = ScreenShot();

            app.RootFrame.Background = ImageBrushFromBitmap(screenShot);

            formImages.Push(Name);
            StoreScreenShot(Name, screenShot);

        } else if (e.NavigationMode == NavigationMode.Back) {
            if (formImages.Count > 0)
                app.RootFrame.Background = ImageBrushFromBitmap(FetchScreenShot(formImages.Pop()));
            else {
                //we're backing out of the last form so reset the background
                app.RootFrame.Background = null;
                RemoveCachedScreenshots();
            }
        }
    }

    public static void RemoveCachedScreenshots() {
        using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication()) {
            string path = Path.Combine(screenshotDir, "*" + screenFileType);
            try {
                string[] fileList = store.GetFileNames(path);
                foreach (string f in fileList) {
                    store.DeleteFile(Path.Combine(screenshotDir, f));
                }
            } catch {

            }
        }
    }
}

Answer 2

请在 App.xaml.cs 中检查你的RootFrame的类型，如果要使用 NavigationTransition ，它必须是TransitionFrame 。