Xamarin.iOS(百分比进度条)网络图片加载

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用户1103568

修改于 2021-05-21 11:08:34

1.1K0

修改于 2021-05-21 11:08:34

文章被收录于专栏：xamarinxamarin

xamarin

SDWebImage本是ObjC的一个开源控件，在gitub上有对Xamarin的完整binding封装，同时还将其支持UIImageView/UIButton等控件的扩展方法，参考博文的功能说明（SDWebImage）：

功能 1.为UIImageView、UIButton加载网络图片，为Cocoa Touch框架提供缓存管理。

2.异步图片下载

3.异步内存+磁盘图片缓存，自动缓存过期处理。

4.确保同一个url不会被加载很多次

5.确保虚假url不会被重复提交很多次

简单来说就是其能够对网络图片进行内存管理及本地存储管理，并且能够手工清除内存及本地缓存。

SDWebImage单独使用

1.WebCahce>>UIImageView/UIButton图片加载（可设置默认图片及完成回调）

partial void ImageButton_TouchUpInside (UIButton sender)  
{  
    this.LoadingView.StartAnimating();  
    string url = "http://www.51ppt.com.cn/Article/Uploadphotos_0708/200604/200641473458360.png";  
    this.ImageButton.SetImage(url,UIControlState.Normal,null,SDWebImageOptions.None,(img,error,cache)=>{  
        this.LoadingView.StopAnimating();  
    });  
}

private void LoadClick()  
{  
<span style="white-space:pre">    </span>string url = "http://d.hiphotos.baidu.com/image/pic/item/8cb1cb1349540923b6a062619058d109b2de49e7.jpg";  
    this.LoadingView.StartAnimating ();  
    this.webImageView.SetImage (url,null,SDWebImageOptions.None,null,(img,error,cache)=>{  
        this.LoadingView.StopAnimating();  
    });  
    //this.webImageView.SetImage (url,UIImage.FromFile("temp.png"),SDWebImageOptions.None,null,null);  
}

2.SDWebImageManager单例

1）图片下载

private void SDLoad()  
{  
    string url = "http://g.hiphotos.baidu.com/image/pic/item/3bf33a87e950352a808d060f5043fbf2b3118bcc.jpg";  
    var manager = SDWebImageManager.SharedManager;  
    manager.Download (url,SDWebImageOptions.None,null,CompletedHandler);  
}  
  
void CompletedHandler (UIImage image, NSError error, SDImageCacheType cacheType,bool finshed)  
{  
    Console.WriteLine ("Reuslt>>"+finshed);  
    this.InvokeOnMainThread (()=>{  
        this.TableView.BackgroundColor = UIColor.FromPatternImage(image);  
    });  
}

2）内存清理及本地删除

private void DelClcik( )  
{  
    SDWebImageManager.SharedManager.ImageCache.ClearMemory ();  //清空内存  
    SDWebImageManager.SharedManager.ImageCache.ClearDisk ();    //清除本地  
}

SDWebImage与进度条使用

1.RadialProgressView/UIProgressView

三种类型Big，Small，Tiny

public override void ViewDidLoad ()  
{  
    base.ViewDidLoad ();  
    // Add our different styles of RadialProgressViews  
    bigRadialProgressView = new RadialProgressView ();  
    bigRadialProgressView.Center = new PointF (View.Center.X, View.Center.Y - 100);  
    bigRadialProgressView.AutoresizingMask = UIViewAutoresizing.FlexibleMargins;  
    View.AddSubview (bigRadialProgressView);  
  
    smallRadialProgressView = new RadialProgressView (RadialProgressViewStyle.Small);  
    smallRadialProgressView.ProgressColor = UIColor.Gray;  
    smallRadialProgressView.Center = new PointF (bigRadialProgressView.Frame.Left / 2, bigRadialProgressView.Center.Y);  
    smallRadialProgressView.AutoresizingMask = UIViewAutoresizing.FlexibleMargins;  
    View.AddSubview (smallRadialProgressView);  
  
    tinyRadialProgressView = new RadialProgressView (RadialProgressViewStyle.Tiny);  
    tinyRadialProgressView.ProgressColor = UIColor.White;  
    tinyRadialProgressView.Center = new PointF (bigRadialProgressView.Frame.Right + (View.Frame.Width - bigRadialProgressView.Frame.Right) / 2, bigRadialProgressView.Center.Y);  
    tinyRadialProgressView.AutoresizingMask = UIViewAutoresizing.FlexibleMargins;  
    View.AddSubview (tinyRadialProgressView);  
  
    standardProgressView = new UIProgressView (UIProgressViewStyle.Bar);  
    standardProgressView.Frame = new RectangleF (30, bigRadialProgressView.Frame.Bottom + 80, View.Frame.Width - 60, 10);  
    standardProgressView.AutoresizingMask = UIViewAutoresizing.FlexibleBottomMargin | UIViewAutoresizing.FlexibleTopMargin | UIViewAutoresizing.FlexibleWidth;  
    View.AddSubview (standardProgressView);  
  
    startProgressButton = UIButton.FromType (UIButtonType.RoundedRect);  
    startProgressButton.Frame = new RectangleF (50, standardProgressView.Frame.Bottom + 40, View.Frame.Width - 100, 30);  
    startProgressButton.SetTitle ("Start Progress", UIControlState.Normal);  
    startProgressButton.AutoresizingMask = UIViewAutoresizing.FlexibleBottomMargin | UIViewAutoresizing.FlexibleTopMargin | UIViewAutoresizing.FlexibleWidth;  
    startProgressButton.TouchUpInside += OnStartProgressTapped;  
    View.AddSubview (startProgressButton);  
}

2.SDWebImage回调操作

void OnStartProgressTapped (object sender, EventArgs e)  
{  
    string url = "http://g.hiphotos.baidu.com/image/pic/item/3bf33a87e950352a808d060f5043fbf2b3118bcc.jpg";  
  
    standardProgressView.Progress = 0;  
    bigRadialProgressView.Reset ();  
    smallRadialProgressView.Reset ();  
    tinyRadialProgressView.Reset ();  
  
    this.ImageView.SetImage (url,null, SDWebImageOptions.SDWebImageProgressiveDownload, ProgressHandler, CompletedHandler);  
}  
  
/// <summary>  
/// 实时下载数据  
/// </summary>  
/// <param name="receivedSize">当前下载量.</param>  
/// <param name="expectedSize">总量.</param>  
void ProgressHandler (uint receivedSize, long expectedSize)  
{  
    Console.WriteLine ("receivedSize -- expectedSize -- "+receivedSize+" -- " + expectedSize);  
    var value = (float)receivedSize / (float)expectedSize;  
    if(value != 0){  
        Console.WriteLine ("Value>>"+value);  
        this.InvokeOnMainThread (()=>{  
            bigRadialProgressView.Value = value;  
            smallRadialProgressView.Value = value;  
            tinyRadialProgressView.Value = value;  
            standardProgressView.Progress = value;  
        });  
    }  
}  
  
void CompletedHandler (UIImage image, NSError error, SDImageCacheType cacheType)  
{  
    this.InvokeOnMainThread (()=>{  
        UIView.Animate (0.1f,()=>{  
            bigRadialProgressView.Alpha = 0.0f;  
            smallRadialProgressView.Alpha = 0.0f;  
            tinyRadialProgressView.Alpha = 0.0f;  
            standardProgressView.Alpha = 0.0f;  
        },()=>{  
            bigRadialProgressView.RemoveFromSuperview();  
            smallRadialProgressView.RemoveFromSuperview();  
            tinyRadialProgressView.RemoveFromSuperview();  
            standardProgressView.RemoveFromSuperview();  
        });  
    });  
}

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参考资源

源码：Xamarin studio(5.5.2) Xamarin.iOS(8.2.0.207) Xcode(5.1.1)

原生(SDWebImage)>>https://github.com/rs/SDWebImage/

Xamarin组件(SDWebImage)>>http://components.xamarin.com/view/sdwebimage

Xamarin组件Binding(SDWebImage)>>https://github.com/stampsy/sdwebimage-monotouch

Xamarin组件圆形进度条(Radialprogress)>>http://components.xamarin.com/view/radialprogress

Xamarin三方Binding>>https://github.com/mono/monotouch-bindings