Java 处理:你能在处理类之外画画吗?
我试图将代码组织到可以在主处理类之外绘制的位置,但是,每当我尝试这样做时,就会得到一个Java 处理:你能在处理类之外画画吗?,java,function,class,processing,jetbrains-ide,Java,Function,Class,Processing,Jetbrains Ide,我试图将代码组织到可以在主处理类之外绘制的位置,但是,每当我尝试这样做时,就会得到一个NullPointerExeption public class Processing extends PApplet { PApplet p = new PApplet(); Screen homeScreen = new Screen(new Vector2(0, 0), p); public static void main(String[] args) { P
NullPointerExeption
public class Processing extends PApplet {
PApplet p = new PApplet();
Screen homeScreen = new Screen(new Vector2(0, 0), p);
public static void main(String[] args) {
PApplet.runSketch(new String[]{"Processing"},
new Processing());
}
public void settings() {
// Setup
size(500, 500);
TextBox t = new TextBox(new Vector2(0, 0), new Vector2(300, 300), new PApplet());
homeScreen.addContent(t);
}
}
我正在调用下面显示的TextBox
类中的display()
方法
public void display() {
// Text Box Body
p.pushMatrix();
p.fill(240);
p.rect(pos.getPos()[0], pos.getPos()[1], dimensions.getPos()[0], dimensions.getPos()[1]);
}
java.lang.NullPointerException
at processing.core.PApplet.pushMatrix(PApplet.java:13149)
at TextBox.display(Processing.java:154)
at Screen.display(Processing.java:83)
at Processing.draw(Processing.java:29)
at processing.core.PApplet.handleDraw(PApplet.java:2426)
at processing.awt.PSurfaceAWT$12.callDraw(PSurfaceAWT.java:1557)
at processing.core.PSurfaceNone$AnimationThread.run(PSurfaceNone.java:316)
Process finished with exit code 0
p
是通过构造函数传递的PApplet
对象。例外情况如下所示
public void display() {
// Text Box Body
p.pushMatrix();
p.fill(240);
p.rect(pos.getPos()[0], pos.getPos()[1], dimensions.getPos()[0], dimensions.getPos()[1]);
}
java.lang.NullPointerException
at processing.core.PApplet.pushMatrix(PApplet.java:13149)
at TextBox.display(Processing.java:154)
at Screen.display(Processing.java:83)
at Processing.draw(Processing.java:29)
at processing.core.PApplet.handleDraw(PApplet.java:2426)
at processing.awt.PSurfaceAWT$12.callDraw(PSurfaceAWT.java:1557)
at processing.core.PSurfaceNone$AnimationThread.run(PSurfaceNone.java:316)
Process finished with exit code 0
如果我将pushMatrix()
注释掉,同样的错误也会发生,只是指向fill()
函数
谢谢你的帮助 注意:您正在创建多个
PApplet
实例,这将使您的代码混乱,并会遇到错误。Processing
类已经扩展了PApplet
,因此删除此行PApplet p=new PApplet()代码>并将其替换为处理p=this代码>或代替新屏幕(新向量2(0,0),p)
您可以像这样使用this
关键字:新建屏幕(新向量2(0,0),this)代码>-谢谢@sorifiend注意:您正在创建多个PApplet
实例,这将使您的代码混乱,并且会遇到错误。Processing
类已经扩展了PApplet
,因此删除此行PApplet p=new PApplet()代码>并将其替换为处理p=this代码>或代替新屏幕(新向量2(0,0),p)
您可以使用this
关键字,如sonew屏幕(new Vector2(0,0),this)代码>