[我正在尝试对LibGDX上的类进行一些JUnit测试,但是在尝试初始化所述类时出现NullPointerError,这可以追溯到使用ShapeRenderer。
这是我初始化的班级:
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.kroy.game.Point;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
import java.util.ArrayList;
import static java.lang.Math.abs;
public class Entity{
int health;
int range;
public Point position;
ShapeRenderer shape = new ShapeRenderer();
public Sprite drawable;
public Entity(int health, int range, Point position,Texture img){
this.health = health;
this.range = range;
this.position = position;
this.drawable = new Sprite(img);
drawable.setPosition(position.x - drawable.getWidth()/2,position.y - drawable.getHeight()/2);
}
public boolean inRange(Entity target){
if(abs(target.position.x - this.position.x) < this.range &&
abs(target.position.y - this.position.y) < this.range){
return true;
}
return false;
}
public void drawBox(ArrayList<Entity> target, OrthographicCamera camera, Sprite sprite) {
shape.setProjectionMatrix(camera.combined);
shape.begin(ShapeType.Line);
boolean redBox = false;
for(Entity entity : target) {
if (this.inRange(entity)) {
redBox = true;
}
}
if (redBox) {
shape.setColor(Color.RED);
}
else {
shape.setColor(Color.GREEN);
}
shape.rect(position.x - range, position.y - range, range * 2, range * 2);
shape.end();
}
}
这里是EntityTest的相关代码:
import com.kroy.entities.Entity;
import com.kroy.game.Point;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.Assertions;
class EntityTest {
@Test
public void testInRangeBoundary() {
Entity e = new Entity(0,5, new Point(5,5));
Assertions.assertTrue(e.inRange(new Entity(0,0,new Point(9,0))));
}
}
这是我得到的错误:
java.lang.NullPointerException
at com.badlogic.gdx.graphics.glutils.ShaderProgram.loadShader(ShaderProgram.java:209)
at com.badlogic.gdx.graphics.glutils.ShaderProgram.compileShaders(ShaderProgram.java:188)
at com.badlogic.gdx.graphics.glutils.ShaderProgram.<init>(ShaderProgram.java:171)
at com.badlogic.gdx.graphics.glutils.ImmediateModeRenderer20.createDefaultShader(ImmediateModeRenderer20.java:233)
at com.badlogic.gdx.graphics.glutils.ImmediateModeRenderer20.<init>(ImmediateModeRenderer20.java:56)
at com.badlogic.gdx.graphics.glutils.ShapeRenderer.<init>(ShapeRenderer.java:116)
at com.badlogic.gdx.graphics.glutils.ShapeRenderer.<init>(ShapeRenderer.java:111)
at com.badlogic.gdx.graphics.glutils.ShapeRenderer.<init>(ShapeRenderer.java:107)
at com.kroy.entities.Entity.<init>(Entity.java:22)
at EntityTest.testInRangeBoundary(EntityTest.java:10) <19 internal calls>
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540) <9 internal calls>
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540) <21 internal calls>
(对于参考线22是'ShapeRenderer shape = new ShapeRenderer();'行)
我知道NullPointerException通常意味着尚未初始化,但是我不确定该怎么做。
任何帮助将不胜感激!
Gdx.gl
字段一样,在测试过程中Gdx
为空。这里发生的是您正在Entity构造函数中创建一个新的ShapeRenderer对象。然后,ShapeRenderer尝试访问libGDX的渲染API,但是它们没有初始化,因此会出现异常。
由于您并未真正测试实体是否正确绘制,但是inRange
方法是否正常工作,所以您希望避免在测试期间调用任何libGDX的API。
有许多解决方案。您可以重新排列代码:
Entity
类和EntityRenderer
类。您只测试前者。drawBox
方法。如果我没记错的话,ShapeRenderer是相当重的对象,因此如果您有很多实体,您可能还是想这样做。另一种可能性是在测试期间模拟libGDX的API。
Gdx.gl = mock(GL20.class)
。HeadlessApplication
类的Gdx
。这两个选项均为described here。但是,最好在可能的情况下重构代码,这是将游戏逻辑和渲染分开的一种好习惯。