Drag and driop image xamarin android

Question

Hello

I have an imageview and i would like to drag and drop

 <ImageView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
        android:id="@+id/queen1"
        android:layout_below="@+id/boardgame"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="10dp"
        android:layout_alignParentLeft="true"/>

in the mainactivity.cs

public class MainActivity : Activity
    {

        ImageView queen1;
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.activity_main);

             queen1 = FindViewById<ImageView>(Resource.Id.queen1);   
                Loadimage();

            };



private async void Loadimage()
        {
            var stream = Assets.Open("queens.png");
            var bitmap = await BitmapFactory.DecodeStreamAsync(stream);
            queen1.SetImageBitmap(bitmap);
            stream.Close();

        }

        }

Thanks

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

I have an imageview and i would like to drag and drop

If you want to drag or drop image in the xamarin.android, we can achieve it by ImageView's SetOnTouchListener. Then detect MotionEventActions.Move event, we can set the X, Y position in the RelativeLayout.

Here is demo code.

   protected override void OnCreate(Bundle savedInstanceState)  
           {  
               base.OnCreate(savedInstanceState);  
               Xamarin.Essentials.Platform.Init(this, savedInstanceState);  
     
               //Get the screensize  
               DisplayMetrics displaymetrics = new DisplayMetrics();  
               WindowManager.DefaultDisplay.GetMetrics(displaymetrics);  
               int screenWidth = displaymetrics.WidthPixels;  
               int screenHeight = displaymetrics.HeightPixels;  
     
               SetContentView(Resource.Layout.activity_main);  
     
               ImageView imageView1 = FindViewById<ImageView>(Resource.Id.imageView1);  
               imageView1.SetOnTouchListener(new MyTouchListener(imageView1, screenWidth, screenHeight));  
           }  

Here is MyTouchListener.cs.

   internal class MyTouchListener : Java.Lang.Object, View.IOnTouchListener  
       {  
           public MyTouchListener(ImageView imageView1, int screenWidth, int screenHeight)  
           {  
               ImageView1 = imageView1;  
               ScreenWidth = screenWidth;  
               ScreenHeight = screenHeight;  
           }  
     
           public ImageView ImageView1 { get; }  
           public int ScreenWidth { get; }  
           public int ScreenHeight { get; }  
     
           public bool OnTouch(View v, MotionEvent e)  
           {  
              var layoutParams1 = (RelativeLayout.LayoutParams)ImageView1.LayoutParameters;  
               // throw new System.NotImplementedException();  
     
               switch (e.ActionMasked)  
             {  
               case MotionEventActions.Down:  
                   break;  
               case MotionEventActions.Move:  
     
                   int x_cord = (int) e.RawX;  
                   int y_cord = (int)e.RawY;  
                   if (x_cord > ScreenWidth) {  
                       x_cord = ScreenWidth;  
                   }  
                   if (y_cord > ScreenHeight) {  
                       y_cord = ScreenHeight;  
                   }  
                   //You can adjust the Image postion when you are draging.  
                   layoutParams1.LeftMargin = x_cord ;  
                   layoutParams1.TopMargin = y_cord-55 ;  
                  ImageView1.LayoutParameters=layoutParams1;  
                   break;  
     
               default:  
                   break;  
              }  
               return true;  
           }  
       }  

Best Regards,

Leon Lu

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