When does the Bitmap property of a PreviewView become available?

Nathan Sokalski 4,121 Reputation points
2023-04-04T04:58:13.2433333+00:00

I have an AndroidX.Camera.View.PreviewView from which I want to continuously/periodically look at the value of the Bitmap property. However, immediately after starting the preview, the Bitmap property is null, so trying to look at the Bitmap property is not possible, and I am not sure how to detect when it becomes available. If possible, I do not want to stop displaying preview when looking at the Bitmap property. How can I detect when the Bitmap property becomes available?

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  1. Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 36,951 Reputation points Microsoft Vendor
    2023-04-05T02:12:09.4+00:00

    Hello,

    After further investigation, you could detect to Bitmap's values using delegates and non-blocking threads, please refer to the following code example:

    public delegate void DelegateWithParameters(PreviewView p);
    
    // implement the delegate method
    private void DetectBitMap(PreviewView p)
    {
        while (true)
        {
            if (p.Bitmap != null)
            {
                ...
            }
        }
    }
    
    // invoke this method
    DelegateWithParameters delFoo =
    new DelegateWithParameters(DetectBitMap);
    delFoo.BeginInvoke(viewFinder, null, null);
    

    Best Regards,

    Alec Liu.


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