Is it possible to respond to the volume and power buttons while the app is not in the foreground? Much like the screen capture capability when holding volume down and the power button. What api calls are necessary to do that? How do I get my app to listen to hardware key events of the entire system regardless of the current app in the foreground?
You can't remove that option from the system settings interface.
However, if you don't want cached data (files) to be deleted, don't store them in the cache. I'm assuming that you're working on an app of your own so that you have control over where your app data is being stored. Use of the cache doesn't happen arbitrarily... it's something that the app developer must implement.
When all else fails reading the docs is worth a try. It's no harder than reading anything somebody may post on this forum!
I have an rotated textview and I want to drag and drop this view.
The problem is that the drag shadow has no rotation.
I found a solution for android in java but this does not work for me.
Maybe I translate the code wrong
<a href="https://stackoverflow.com/questions/17049938/how-to-drag-a-rotated-dragshadow"></a>[<a href="https://stackoverflow.com/questions/17049938/how-to-drag-a-rotated-dragshadow" target="_blank" title="New Window">^</a>]
class CustomDragShdowBuilder : View.DragShadowBuilder
private View _view;
public CustomDragShdowBuilder(View view)
_view = view;
public override void OnDrawShadow(Canvas canvas)
double rotationRad = Math.ToRadians(_view.Rotation);
int w = (int)(_view.Width * _view.ScaleX);
int h = (int)(_view.Height * _view.ScaleY);
double s = Math.Abs(Math.Sin(rotationRad));
double c = Math.Abs(Math.Cos(rotationRad));
int width = (int)(w * c + h * s);
int height = (int)(w * s + h * c);
canvas.Scale(_view.ScaleX, _view.ScaleY, width / 2, height / 2);
canvas.Rotate(_view.Rotation, width / 2, height / 2);
canvas.Translate((width - _view.Width) / 2, (height - _view.Height) / 2);
public override void OnProvideShadowMetrics(Point shadowSize, Point shadowTouchPoint)
shadowTouchPoint.Set(shadowSize.X / 2, shadowSize.Y / 2);
I once read an article on how to extract the letters and numbers from a picture of a license plate. It was a fun read but was completely beyond me. I suppose the same would be true in this case. Image processing is a huge and complicated field. I did stumble across this as maybe a starting point.
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