Canvas - getWidth(), getHeight() and Onclicklistener()

Question

I’m making an app for Android using the Canvas class, but I’m having some problems.

1º. When executing the methods below,

canvas.drawText("Width: " + fotoOriginal.getWidth(), 0, 10, paint);
canvas.drawText("Height: " + fotoOriginal.getHeight(), 0, 20, paint);

I see on the screen: "Width: 1580" and "Height: 977", that is, my photo has 1580 x 977 px.

But when I try to write on the screen the width ratio by height,

myRatio = fotoOriginal.getWidth() / fotoOriginal.getHeight();
canvas.drawText("Ratio is: " + myRatio, 0, 30, paint);

the result that appears on the screen is 1.0 . No matter what I do, the result is always 1 or 0. Why does not appear the real reason of the image, ie 1,617...?

second. As I said, the methods getWidth() and getHeight() return me 1580 and 977, respectively, but when I go in the photo file and leave the mouse on top of it, it appears "Dimensions: 1053 x 651", the same dimension that appears in Paint. Why is there a difference in dimension?

3°. What is the most correct (and where) way for me to add Onclicklistener(), for example to draw anything on Canvas when a user clicks on the screen?

Follows the code:

public class MyActivity extends Activity{

public int teste = 0;

DrawView drawView;

public static int width;
public static int height;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Para a activity pegar a tela inteira
    fullscreen();

    // Para saber o tamanho da tela
    Display display = getWindowManager().getDefaultDisplay();

    Point size = new Point();
    display.getSize(size);
    width = size.x;
    height = size.y;

    Toast.makeText(getApplicationContext(), "Screen size is: " + width + " px (X), and " + height + "px (Y)!", Toast.LENGTH_LONG).show();

    // DrawView
    drawView = new DrawView(this);
    drawView.setOnClickListener(new HeyClick());
    drawView.setBackgroundColor(Color.WHITE);

    setContentView(drawView);

}

public void fullscreen(){

    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

}

public class HeyClick implements View.OnClickListener{

    @Override
    public void onClick(View v) {

        Toast.makeText(getApplicationContext(), "" + teste, Toast.LENGTH_SHORT).show();
        teste++;

    }

}

}

The other class:

public class DrawView extends View{

Paint paint = new Paint();

int x = MyActivity.width;
int y = MyActivity.height;

Bitmap fotoOriginal;
Bitmap fotoScaled;
float myRatio;


public DrawView(Context context) {
    super(context);

    paint.setColor(Color.BLACK);

    fotoOriginal = BitmapFactory.decodeResource(getResources(), R.drawable.ilha_de_malaga_transparente);
    fotoScaled = Bitmap.createScaledBitmap(fotoOriginal, x, y, false);

    myRatio = fotoOriginal.getWidth() / fotoOriginal.getHeight();

}

@Override
protected void onDraw(Canvas canvas) {

    canvas.drawBitmap(fotoScaled,0,0, paint);
    canvas.drawText("Width: " + fotoOriginal.getWidth(), 0, 10, paint);
    canvas.drawText("Height: " + fotoOriginal.getHeight(), 0, 20, paint);
    canvas.drawText("Ratio is: " + myRatio, 0, 30, paint);

}

}

Answer 1

Your problem is that you are actually dividing two integers and the result turns out to be another integer.

You can cast one of the operators to float that the split result will also be a float.

myRatio = (float)fotoOriginal.getWidth() / fotoOriginal.getHeight();

If you want to show only two decimal places you can use String.format

canvas.drawText(String.format("Ratio is: %.2f", myRatio), 0, 30, paint);