组合两个位图图像时出现空指针异常

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;

public class BitmapCombiner {
    public static Bitmap combineBitmaps(String bitmapPath1, String bitmapPath2) {
        Bitmap bitmap1 = BitmapFactory.decodeFile(bitmapPath1);
        Bitmap bitmap2 = BitmapFactory.decodeFile(bitmapPath2);

        if (bitmap1 == null || bitmap2 == null) {
            throw new NullPointerException("位图文件读取失败");
        }

        int width = bitmap1.getWidth() + bitmap2.getWidth();
        int height = Math.max(bitmap1.getHeight(), bitmap2.getHeight());

        Bitmap combinedBitmap = Bitmap.createBitmap(width, height, bitmap1.getConfig());
        Canvas canvas = new Canvas(combinedBitmap);
        Paint paint = new Paint();

        canvas.drawBitmap(bitmap1, 0, 0, paint);
        canvas.drawBitmap(bitmap2, bitmap1.getWidth(), 0, paint);

        return combinedBitmap;
    }
}