Android setX() and setY() behaving weird

Question

I am trying to dynamically create and then move an image in an Android activity. However, the setX() and setY() methods seem to not work correctly. It correctly sets the position of an image when it is first created and placed, but any attempt to update it results in the image being placed in the wrong spot. For instance, the image moves on the following code:

ImageView image;
RelativeLayout layout = (RelativeLayout)findViewById(R.id.activity_this);

if(action == MotionEvent.ACTION_DOWN){

    image = new ImageView(MyClass.this);                            
    layout.addView(image, width, height);   
    image.setX(206);
    image.setY(206);
}
else if(action == MotionEvent.ACTION_MOVE){

    if(image != null){
        image.setX(206);
        image.setY(206);
    }
}

On ACTION_MOVE the image is moved even though the x and y position values remain the same. The parent of the image remains the same. The size remains the same. If I get the x and y values it will still say 206, but it is not placed at (206, 206) on the activity anymore. I am lost as to why this is happening. I can't find any indication that the image has been altered except for it physically changing location.

Answer 1

Run into the same issue. View.setLeft(int)/View.setTop(int) worked for me.

Note that since the original post of this answer things changed and on the more recent android versions it may produce unexpected results while it did the trick for me on older versions. So if you are targeting older devices (android 3.0 and below) this may help but for a more generic solution please consider other answers here as well.

Answer 2

From the docs, setTranslationX is:

Sets the horizontal location of this view relative to its left position. This effectively positions the object post-layout, in addition to wherever the object's layout placed it.

And setX is:

Sets the visual x position of this view, in pixels. This is equivalent to setting the translationX property to be the difference between the x value passed in and the current left property.

Thus you can think of setTranlsationX as a relative offset: move 3 pixels left of where you normally would be. And setX is a fixed position: move whatever you have to so that you end up drawing at coordinate X.

Answer 3

Really, this shouldn't be happening. Alternatively, try setting another variable and setting x and y to it, or get x and get y and add a 0 to each one of them for same location.

As stated in Android - Use of view.setX() and setY in api 8, if you have searched, there is another solution that also works even before api 8. LayoutParams works like this -

RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT); //WRAP_CONTENT param can be FILL_PARENT
params.leftMargin = 206; //XCOORD
params.topMargin = 206; //YCOORD
childView.setLayoutParams(params);

There is more information there. I hope this helps