如何在绘图画布上为油漆的单个部分设置动画？

Question

我正在制作自定义视图应用程序。我想在onDraw画布上设置paint的单个部分（Tap to start），这是我的代码，我从互联网调整了源代码并将其放入我的应用程序中。

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Animation;
import android.view.animation.ScaleAnimation;
import android.widget.ImageView;

public class CustomView extends ImageView{

    private static Paint paint;
    private int w;
    private int h;
    private Animation scaleAnim;




public CustomView(Context context, AttributeSet attrs) {
    super(context, attrs);

    //To customize the brown border
    paint = new Paint();
    paint.setStrokeWidth(20);
    paint.setColor(Color.rgb(123, 92, 13));
    paint.setStyle(Paint.Style.STROKE);
    }

//To fit with the situation of vertical and horizontal orientation
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    this.w = w;
    this.h = h;
    super.onSizeChanged(w, h, oldw, oldh);
}

private void createAnim(Canvas canvas) {

    scaleAnim = new ScaleAnimation(0f,1f,0f,1f,Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f);

    scaleAnim.setRepeatMode(Animation.REVERSE);

    scaleAnim.setRepeatCount(Animation.INFINITE);

    scaleAnim.setDuration(10000L);

    scaleAnim.setInterpolator(new AccelerateDecelerateInterpolator());



             startAnimation(scaleAnim);

         }

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    // creates the animation the first time
    if (scaleAnim == null) {
        createAnim(canvas);
    }

    //To obtain the height and width
    int height = this.getMeasuredHeight();
    int width = this.getMeasuredWidth();

    //To draw the dark green background
    canvas.drawColor(Color.rgb(15, 37, 7));
    //To paint the brown border
    canvas.drawRect(10, 10, width - 10, height - 10, paint);

    //To obtain the image
    Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.main_icon);
    //To place the image on the right bottom corner
    canvas.drawBitmap(bmp, canvas.getWidth()-bmp.getWidth(), canvas.getHeight()-bmp.getHeight() , paint);

    //To obtain the custom font and make it available to use
    Typeface typeface = Typeface.createFromAsset(getContext().getAssets(),
            "fonts/KG.ttf");    

    //To create a new paint style for text
    Paint textStyle = new Paint();
    //Set the font style
    textStyle.setTypeface(typeface);
    //To set text color to white
    textStyle.setColor(Color.rgb(255, 255, 255));
    //To set text size
    textStyle.setTextSize(100);
    //To make text centered
    textStyle.setTextAlign(Align.CENTER);
    //To print the text as main title with style specified
    canvas.drawText("L E A R N E R !", w/2, h/2, textStyle);

    //To create a new paint and customize them
    Paint jpStyle = new Paint();
    jpStyle.setColor(Color.rgb(252,71,71));
    jpStyle.setTextSize(50);
    jpStyle.setTextAlign(Align.CENTER);
    jpStyle.setTypeface(typeface);
    canvas.drawText("@ J A P A N", w/2, h/2+50, jpStyle);

    //To create a new paint and customize them
    Paint startStyle = new Paint();
    startStyle.setColor(Color.WHITE);
    startStyle.setTextSize(40);
    startStyle.setTextAlign(Align.CENTER);
    startStyle.setTypeface(typeface);
    canvas.drawText("> Tap to Start <", w/2, h/2+170, startStyle);



    }


}