how to draw a square in the centre of the screen in android

Question

I am tring to draw a square in the center of the screen. I want there to be a slight margin to the left and right of the square so that is is away from the edge, the way I am trying to create it is below. The problem is that it will not display properly on all devices and that when the screen is tilted some of the square is cut off. I think this is because I use rectSide = 1000. does anybody know a better way to do this that will work on any screen size?

int rectside =1000;
canvas.drawRect(width/2 - rectSide/2,
                height/2 - rectSide/2,
                width/2 + rectSide/2,
                height/2 + rectSide/2, paint);

1000 pixels seems a big amount, to me. Also, if it's in the center... it's already away from the edges. You don't need to cut some extra size. — Phantômaxx, Jun 22 '15 at 08:15

Shakeeb Ayaz · Answer 1 · 2015-06-22T08:20:41.860

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You need to get height and width of device programmatically like this

 DisplayMetrics displaymetrics = new DisplayMetrics();
 getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
 int height = displaymetrics.heightPixels;
 int width = displaymetrics.widthPixels;

Update:As pointed out by @Der Golem take the smaller between width and height so that all sides should be equal

edited Jun 22 '15 at 08:20

answered Jun 22 '15 at 08:15

Shakeeb Ayaz

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... and then take the **smaller** between `width` and `height. – Phantômaxx Jun 22 '15 at 08:16
what do you mean take the smaller between height and width? – Ciaran Jun 22 '15 at 08:17
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Since you want a **square**, the dimensions must be **identical**. – Phantômaxx Jun 22 '15 at 08:18

score 1 · Answer 2 · answered Jun 22 '15 at 09:21

Get the device's dimension:

DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
int height = displaymetrics.heightPixels;
int width = displaymetrics.widthPixels;

Next, get the smallest dimension:

int diameter = width;
if (height < width){
    diameter = height;
}

Now get an offset, I suggest using some kind of percentage of the device, e.g.

int offset = (int) (0.05*diameter);
diameter -= offset;

Finally draw it:

canvas.drawRect(width/2 - diameter/2 ,
                height/2 - diameter/2,
                width/2 + diameter/2,
                height/2 + diameter/2, paint);

Before I forget, if the landscape changes mess up your rectangle, make sure to put all of this in a method which you can redraw whenever a UI update is required (and don't forget to clear the canvas :) ). — Roel Strolenberg, Jun 22 '15 at 09:30

score 0 · Answer 3 · edited May 23 '17 at 10:26

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You are right, using an absolute number of pixel is not the good way.

You should adapt your rectSide using display height & width. How to get screen size attributes has already been discussed here.

I also strongly recommend you to read this, to get a better understanding of how to manage multiple screen sizes.

edited May 23 '17 at 10:26

Community

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answered Jun 22 '15 at 08:21

mlumeau

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Along with the link u should also add code snippets too.Otherwise someone can downvote u – Shakeeb Ayaz Jun 22 '15 at 10:07

how to draw a square in the centre of the screen in android

3 Answers3