Android 2d图形帧率

Question

I'm in need of assistance with the program that I'm writing.

The code basically list of words from an array, chops it into specific Strings at certain indexes, then into Chars and displaying it into the canvas.

Then, the chars animates while sliding down the canvas.

But, whenever it animates slowly, the characters are on top of each other, and whenever it animates fast, the characters are separated.

How do I get the chars to be separated equally WHILE animating slowly? One solution I came up with was to find a way to edit the frame rate, but I don't know how to do it :(.

 public sketchUp(Context context) {
        super(context);
    }
String arr [] = {"love","happiness"};
    protected void onDraw (Canvas canvas){
super.onDraw(canvas);
        Rect disRect = new Rect();
      disRect.set(0,0, canvas.getWidth(), canvas.getHeight()/2);
        Paint col = new Paint();
        Paint txt = new Paint();
        txt.setTextSize(20);
        txt.setColor(Color.BLACK);
        col.setColor(Color.GREEN);
        col.setStyle(Paint.Style.FILL);
        canvas.drawRect(disRect, col);

        if(y<canvas.getHeight()/2){
            y+=1;
        }
       else{
            y=0;
        }
//       if(x<canvas.getWidth()){
//            x+=10;
//        }
//        else{
//           x=0;
//       }
   for(int i=0; i<arr.length; i++){

    for(int j=0; j<arr[i].length(); j++){
        char result = arr[i].charAt(j);
//        System.out.println(result);
    canvas.drawText(String.valueOf(result), x, y+=0.5, txt);
//

    }
   }

invalidate();

    }

Answer 1

Think of it this way:

That y+=0.5 sets the separation of the characters. It is the only thing that makes each character's position different. If it was just y , the characters would be on top of each other.

Why it affects animation speed

Each y+=0.5 changes y. So after drawing the characters y is lower than it was before.

How to fix this

First, you have to decide what y is supposed to be. You should rename it, so you remember what it is. For example it could become firstCharacterY .

Obviously, the first characters y should not change when drawing the characters, but should change each frame. To fix the drawing part, you can either set y = firstCharacterY - 0.5 before the loop or calculate y from i and j each iteration.