從Stream/StreamReader將圖像加載到圖像或RawImage組件

Question

我正在使用AWS Unity（v3.3.50.0）：從https://aws.amazon.com/mobile/sdk/下載的S3 SDK（AWSSDK.S3.3.3.5.4.unitypackage）。 我的Unity版本是5.5.1。

我想下載放置在S3存儲桶上的映像，存儲桶已配置並且可以下載。我看到這個字符串是作爲響應的數據。

但我無法在S3示例GetObject（）函數中將返回的StreamReader轉換爲UnityEngine.UI.Image.sprite或UnityEngine.UI.RawImage.texture。需要對此:)

的S3存儲圖像是PNG格式

private void GetObject() 
{ 
    ResultText.text = string.Format("fetching {0} from bucket {1}", SampleFileName, S3BucketName); 
    Client.GetObjectAsync(S3BucketName, SampleFileName, (responseObj) => 
     { 
      string data = null; 
      var response = responseObj.Response; 
      if (response.ResponseStream != null) 
      { 
       using (StreamReader reader = new StreamReader(response.ResponseStream)) 
       { 
        data = reader.ReadToEnd(); 
       } 

       ResultText.text += "\n"; 
       ResultText.text += data; 
      } 
      Debug.Log("GetObject: " + data); 
     }); 
} 

幫助。但在未來的JPG中，必須啓用JPEG格式支持。

Answer 1

StreamReader用於文本而不是二進制數據，如要下載的圖像。我可以告訴你爲什麼使用它，並且不能告訴你爲什麼在圖像上執行Debug.Log("GetObject: " + data);。

下載的圖像，然後使用Texture2D.LoadImage將其轉換爲的Texture2D，你就可以加載到你的RawImage顯示。

public RawImage displayTexture; 

private void GetObject() 
{ 
    ResultText.text = string.Format("fetching {0} from bucket {1}", SampleFileName, S3BucketName); 
    Client.GetObjectAsync(S3BucketName, SampleFileName, (responseObj) => 
    { 
     byte[] data = null; 
     var response = responseObj.Response; 
     if (response.ResponseStream != null) 
     { 
      using (StreamReader reader = new StreamReader(response.ResponseStream)) 
      { 
       using (var memstream = new MemoryStream()) 
       { 
        var buffer = new byte[512]; 
        var bytesRead = default(int); 
        while ((bytesRead = reader.BaseStream.Read(buffer, 0, buffer.Length)) > 0) 
         memstream.Write(buffer, 0, bytesRead); 
        data = memstream.ToArray(); 
       } 
      } 

      //Display Image 
      displayTexture.texture = bytesToTexture2D(data); 
     } 
    }); 
} 

public Texture2D bytesToTexture2D(byte[] imageBytes) 
{ 
    Texture2D tex = new Texture2D(2, 2); 
    tex.LoadImage(imageBytes); 
    return tex; 
} 

就像我上面提到的，使用StreamReader對二進制數據不好。你可以使用MemoryStream來做到這一點。在這種情況下，您的新GetObject功能應如下所示：

private void GetObject() 
{ 
    ResultText.text = string.Format("fetching {0} from bucket {1}", SampleFileName, S3BucketName); 
    Client.GetObjectAsync(S3BucketName, SampleFileName, (responseObj) => 
    { 
     byte[] data = null; 
     var response = responseObj.Response; 
     Stream input = response.ResponseStream; 

     if (response.ResponseStream != null) 
     { 
      byte[] buffer = new byte[16 * 1024]; 
      using (MemoryStream ms = new MemoryStream()) 
      { 
       int read; 
       while ((read = input.Read(buffer, 0, buffer.Length)) > 0) 
       { 
        ms.Write(buffer, 0, read); 
       } 
       data = ms.ToArray(); 
      } 

      //Display Image 
      displayTexture.texture = bytesToTexture2D(data); 
     } 
    }); 
}