Java 从另一个类访问JLabel
因此,我试图从“Controle”类访问“TesteRotulo”类中的(唯一)标签“lblNewLabel” 应访问TesteRotulo中标签的类控件Java 从另一个类访问JLabel,java,swing,Java,Swing,因此,我试图从“Controle”类访问“TesteRotulo”类中的(唯一)标签“lblNewLabel” 应访问TesteRotulo中标签的类控件 public class Controle { private TesteRotulo jM; private JFrame janela; private JLabel rotulo; public Controle(TesteRotulo jM) { this.jM = jM;
public class Controle {
private TesteRotulo jM;
private JFrame janela;
private JLabel rotulo;
public Controle(TesteRotulo jM) {
this.jM = jM;
}
public void setRotulo() {
this.rotulo = jM.getLblNewLabel();
rotulo.setText("teste");
}
}
因此,我认为拥有TesteRotulo(唯一)实例的引用,我应该能够访问标签。
但是没有用。始终获取空指针异常。
怎么了?
先谢谢你 初始化中的标签是局部变量<代码>JLabel lblNewLabel=新JLabel()代码>
您应该编写
this.lblNewLabel=newjlabel()代码>非常感谢!我通过EclipseWindowBuilder在RealProject中实现了GUI(在标签中显示“n”个图像),并对此进行了讨论!
public class Controle {
private TesteRotulo jM;
private JFrame janela;
private JLabel rotulo;
public Controle(TesteRotulo jM) {
this.jM = jM;
}
public void setRotulo() {
this.rotulo = jM.getLblNewLabel();
rotulo.setText("teste");
}
}