OnActivityResult（蓝牙）中的 Intent 数据为空

Question

Need help. I want to pass data to the CallBack method, but I get a null value.

Intent enableBt = new Intent(BluetoothAdapter.ActionRequestEnable);
enableBt.PutExtra("Resource", "bluetooth");
StartActivityForResult(enableBt, 1);

and

protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
    {
        base.OnActivityResult(requestCode, resultCode, data);
        var resource = data.GetStringExtra("Resource");

But data = null . What is the problem?

Answer 1

Yes, we usually need to use requestCode and resultCode to filter the intent. Besides, we also need to use method SetResult to return the result. You can refer to the following code:

The First Page

Intent intent = new Intent(this, typeof(SecondActivity));
StartActivityForResult(intent, 0x001);

method: OnActivityResult

protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
    {
        base.OnActivityResult(requestCode, resultCode, data);

        if (requestCode == 0x001)
        {
            if (resultCode == Result.Ok)
            {
                string result = data.GetStringExtra("test");

                Toast.MakeText(this,"reslut is: " + result,ToastLength.Short).Show();
            }

        }
    }

The SecondPage

var intent = new Intent();
intent.PutExtra("test", "test..123");
SetResult(Result.Ok, intent);
Finish();