为什么即使我声明了 rand，它也会给我一个错误？

Question

import java.util.Random;

class perro{
    private Float animo;
    private Float umbral;
    Random rand = new Random();
    
    public perro(){
        animo = rand.nextFloat() * (5+5)-5;
        umbral = rand.nextFloat() * (0-20);
    }
    
    public Float getAnimo(){
        return animo;
    }
    
    public Float getUmbral(){
        return umbral;
    }
    
    private void psican(persona p){
        this.animo = (rand.nextFloat() -0.5) * 10 + this.animo;
        if (p.tieneGalleta()){
            p.darGalleta();
            this.animo += (1.0 / p.getConfiabilidad()) * (rand.nextInt(2));
        }
    
    System.out.println("Mi nuevo animo es: " + this.animo);
    }

我收到了这个错误：

 "error: incompatible types: double cannot be converted to Float
            this.animo = (rand.nextFloat() -0.5) * 10 + this.animo;"

我已经检查了所有内容，但是从一开始就将所有内容都表示为浮点数。

Answer 1

因为0.5是double （不是float ）。 改变这个

this.animo = (rand.nextFloat() -0.5) * 10 + this.animo;

至

this.animo = (rand.nextFloat() -0.5f) * 10 + this.animo;

或者

this.animo += (rand.nextFloat() - 0.5f) * 10;