同时旋转和平移位图

Question

I'm creating a live wallpaper in which I want to rotate image 1 on canvas continuously while it moves left to right and so on. I was able to move it from left to right but on applying rotation it gives it in the center with no rotation. My code is given below. I used animations but it has caused error in the live wallpaper.

try {
    c = holder.lockCanvas();
    // clear the canvas
    c.drawColor(Color.BLACK);
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
    if (c != null){
        int width=c.getWidth();
        int degree=0;
        c.drawBitmap(backgroundImage, 0, 0, null);
        Matrix transform = new Matrix();
        // transform.setTranslate(100, 100);
        // transform.preRotate(degree,75 ,100);
        // canvas.drawBitmap(bitmap, transform, null);
        transform.setRotate(degree, x, y);
        c.drawBitmap(image1, transform, null);
        //canvas.rotate(-90);
        if(x>width+100){  
            // assign initial value to start with
            x=-130;
        }
        // change the x position/value by 1 pixel
        x=x+4;
        degree+=45;
        c.restore(); 
    }
}

Answer 1

I don't see you calling c.save(); when you call c.restore() it needs to be paired with a previous c.save().

From the api on restore(): This call balances a previous call to save(), and is used to remove all modifications to the matrix/clip state since the last save call. It is an error to call restore() more times than save() was called.