I wonder how I should increase and decrease the value of
yPos to be able to move a sprite object diagonal and in different angles?
canvas.drawBitmap(image, xPos - (image.getWidth() / 2), yPos - (image.getHeight() / 2), null);
Casper gave a good answer, but you can also use sin and cos to move your sprite at a certain angle:
Of course, depending on what Sine and Cosine functions you're using, you may have to enter the angle in radians/degrees. Seeing as you're using Java, java.lang.Math comes with all the functions you'll need.
For more about sin and cos, look at this.
How about just working it out?
Assuming a coordinate system where 0, 0 is top-left. Defining our object's coordinates as being 0, 0 (x, y).
would move the object 50 pixels diagonally towards the bottom right corner.