从类中调用Activity的方法

Question

I have Activity named BarcodeScanActivity which has a method OnScanDataPass . I want to access this method from a non Activity class (Normal Calss).

public class BarcodeScanActivity : Activity, EMDKManager.IEMDKListener
{
     static IScanDataPass _scanDataPass;

     public void OnScanDataPass(IScanDataPass scanDataPass)
     {
         _scanDataPass = scanDataPass;
     }
}

below is my class

public class ScanCode_Android : IScanCode, IScanDataPass
{
        static Context context = Application.Context;
        private Intent intent = new Intent(context,typeof(BarcodeScanActivity));
        private BarcodeScanActivity scan = new BarcodeScanActivity();

        public ScanCode_Android()
        {
            context.StartActivity(intent);
            scan.OnScanDataPass(this);
        }
}

Above code snippet shows the method i tried. How do I call a method in an activity from a normal class? How can I do it with Intent?

Answer 1

You can not instantiate an Activity manually, the instance of Activity will be instantiated by System, and its process is complex.

---

You can pass the instance of Activity to your Normal Class to achieve your goal:

public class ScanCode_Android : IScanCode, IScanDataPass 
{ 
        BarcodeScanActivity mContext ;

        public ScanCode_Android(BarcodeScanActivity context) 
        {   
            this.mContext=context;
            Intent intent = new Intent(context,typeof(BarcodeScanActivity));
            context.StartActivity(intent);
            context.OnScanDataPass(this);
        } 
}

---

How can I do it with Intent?

You need use Context to deal with it. Like StartActivity, StartService... .

How do I call a method in an activity from a normal class?

Like the above codes, pass Activity to Normal class.

Update:

You can create one pixel Activity to avoid the Activity to been seen.

OnePiexlActivity :

[Activity(Label = "OnePiexlActivity",Theme = "@style/OnePixelActivity")]
public class OnePiexlActivity : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        Window.SetGravity(GravityFlags.Left | GravityFlags.Top);
        WindowManagerLayoutParams layoutParams=  Window.Attributes;
        layoutParams.X = 0;
        layoutParams.Y = 0;
        layoutParams.Height = 1;
        layoutParams.Width = 1;
        Window.Attributes=layoutParams;
        Android.Util.Log.Error("lv","111111111111");

    }
}

style :

<style name="OnePixelActivity" parent="android:Theme.Holo.Light.NoActionBar">
  <item name="android:windowIsTranslucent">true</item>
</style>