/// <summary>
/// Instead of calling "StarterActivity.StartActivityForResult()" directly, we call this
/// awaitable method, which takes care about waiting for the Android event. If the Intent
/// is never finished, the method would not return, but usually this results in a cancel
/// result.
/// </summary>
/// <param name="intentToStart">New indent we want to start, this could for example be a
/// file dialog intent.</param>
/// <returns>Returns the result of the started and awaited intent.</returns>
public async Task <ActivityResult> StartActivityAndWaitForResult(Intent intentToStart)
{
unchecked
{
_requestCode++;
}
StartedActivityInfo activityInfo = new StartedActivityInfo
{
RequestCode = _requestCode,
WaitHandle = new ManualResetEvent(false)
};
_startedActivityInfos.Add(activityInfo);
// Prepare the waiting task
Task <ActivityResult> waiterTask = new Task <ActivityResult>(() =>
{
// Start the activity
StarterActivity.StartActivityForResult(intentToStart, activityInfo.RequestCode);
activityInfo.WaitHandle.WaitOne();
return(activityInfo.Result);
});
// Start the waiting
waiterTask.Start();
return(await waiterTask);
}
/// <summary>
/// The StarterActivity should overwrite the "OnActivityResult()" method and redirect its
/// parameter directly to this method. Afterwards it can call base.OnActivityResult().
/// </summary>
/// <param name="requestCode">The requestCode passed to the StarterActivity.</param>
/// <param name="resultCode">The resultCode passed to the StarterActivity.</param>
/// <param name="data">The data passed to the StarterActivity.</param>
public void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
// Lets see if we have started an activity with this request code.
StartedActivityInfo activityInfo = _startedActivityInfos.Find(item => item.RequestCode == requestCode);
if (activityInfo != null)
{
_startedActivityInfos.Remove(activityInfo);
// Prepare the result and stop the waiting task.
activityInfo.Result = new ActivityResult(resultCode, data);
activityInfo.WaitHandle.Set();
}
}
