xamarin形式的標籤在滾動視圖捏和縮放android

Question

我需要一個大文本的標籤，如需要捏縮放功能的文章，我已經寫了一個ZoomableScrollview在IOS和Windows，但不是在Android中正常工作。請參閱下面的代碼。

守則PCL

public class ZoomableScrollView:ScrollView 
{ 
    public static readonly BindableProperty MinimumZoomScaleProperty = BindableProperty.Create("MinimumZoomScale", typeof(float), typeof(ZoomableScrollView), default(float)); 

    public float MinimumZoomScale 
    { 
     get { return (float)GetValue(MinimumZoomScaleProperty); } 
     set { SetValue(MinimumZoomScaleProperty, value); } 
    } 
    public static readonly BindableProperty MaximumZoomScaleProperty = BindableProperty.Create("MaximumZoomScale", typeof(float), typeof(ZoomableScrollView), default(float)); 

    public float MaximumZoomScale 
    { 
     get { return (float)GetValue(MaximumZoomScaleProperty); } 
     set { SetValue(MaximumZoomScaleProperty, value); } 
    } 
} 

IOS渲染

public class ZoomableScrollViewRenderer : ScrollViewRenderer 
{ 
    protected override void OnElementChanged(VisualElementChangedEventArgs e) 
    { 
     base.OnElementChanged(e); 
     if (e.NewElement == null) 
      return; 

     if (e.OldElement == null) 
     { 
      ZoomableScrollView zsv = Element as ZoomableScrollView; 
      this.MinimumZoomScale = zsv.MinimumZoomScale; 
      this.MaximumZoomScale = zsv.MaximumZoomScale; 
      this.ViewForZoomingInScrollView += (UIScrollView sv) => { return this.Subviews[0]; }; 
     } 
    } 
} 

的Windows渲染

public class ZoomableScrollViewRenderer:ScrollViewRenderer 
{ 
    protected override void OnElementChanged(ElementChangedEventArgs<ScrollView> e) 
    { 
     base.OnElementChanged(e); 
     if (e.NewElement == null) 
      return; 

     if (e.OldElement == null) 
     { 
      ZoomableScrollView zsv = Element as ZoomableScrollView; 
      this.Control.ZoomMode = Windows.UI.Xaml.Controls.ZoomMode.Enabled; 
      this.Control.MinZoomFactor = zsv.MinimumZoomScale; 
      this.Control.MaxZoomFactor = zsv.MaximumZoomScale; 
     } 
    } 
} 

的Android渲染

public class ZoomableScrollViewRenderer:ScrollViewRenderer 
{ 
    float originalDistanceX, currentdistanceX, originalDistanceY, currentdistanceY; 
    bool IsPinching = false; 
    double currentScale; 
    TeluguLabel lbl; 
    ScrollView svMain, svSub; 

    protected override void OnElementChanged(VisualElementChangedEventArgs e) 
    { 
     base.OnElementChanged(e); 
     svMain = ((ScrollView)e.NewElement); 
     lbl = svMain.Content as TeluguLabel; 
     svSub = new ScrollView(); 
     svSub.Orientation = ScrollOrientation.Horizontal; 
     svSub.Content = lbl; 
     svMain.Content = svSub; 
     lbl.AnchorX = 0; 
     lbl.AnchorY = 0; 

    } 
    public override bool OnTouchEvent(MotionEvent e) 
    { 
     if (e.PointerCount > 1) 
     { 
      IsPinching = true; 
      currentScale = lbl.Scale; 
      originalDistanceX = Math.Abs(e.GetX(0) - e.GetX(1)); 
      originalDistanceY = Math.Abs(e.GetY(0) - e.GetY(1)); 
     } 
     else 
     { 
      IsPinching = false; 
     } 
     return base.OnTouchEvent(e); 
    } 
    public override bool DispatchTouchEvent(Android.Views.MotionEvent e) 
    { 
     switch (e.Action) 
     { 
      case MotionEventActions.Down: 
       this.Parent.RequestDisallowInterceptTouchEvent(true); 
       break; 
      case MotionEventActions.Move: 
       if(IsPinching && e.PointerCount > 1) 
       { 
        currentdistanceX = Math.Abs(e.GetX(0) - e.GetX(1)); 
        currentdistanceY = Math.Abs(e.GetY(0) - e.GetY(1)); 
        if (originalDistanceX < currentdistanceX || originalDistanceY < currentdistanceY) 
         lbl.Scale = currentScale + 0.01; 
        else if (originalDistanceX > currentdistanceX || originalDistanceY > currentdistanceY) 
         lbl.Scale = currentScale - 0.01; 
       } 
       break; 
      case MotionEventActions.Up: 
       this.Parent.RequestDisallowInterceptTouchEvent(false); 
       break; 
     } 
     return base.DispatchTouchEvent(e); 
    } 


} 

在android中我能夠在一定程度上實現縮放，但滾動不順暢，但我妥協了。現在問題在於標籤中的文字被剝離了。有人請幫助我，我的應用程序本身是閱讀哪些是他基本功能不工作。 在此先感謝

Answer 1

我明白了。基本上android標籤沒有限制100行，我必須在渲染器中覆蓋它

label.SetMaxLines(4000);