Java无法找到符号错误

时间:2011-11-26 22:59:10

标签: blackberry java-me

我无法弄清楚为什么我会通过以下代码继续收到以下错误:

  

Hello.WorldApp.java:9:net.rim.device.api.ui.UiApplication中的pushScreen(net.rim.device.api.ui.Screen)无法应用于(com.beginningblackberry.helloworld.HelloWorldMainScreen)           pushScreen(mainScreen);

     

HelloWorldMainScreen.java:10:找不到符号   symbol:方法add(net.rim.device.api.ui.component.LabelField)   location:class com.beginningblackberry.helloworld.HelloWorldMainScreen           添加(的labelField);

\\HelloWorldApp.java

package com.beginningblackberry.helloworld;

import net.rim.device.api.ui.UiApplication;

class HelloWorldApp extends UiApplication {    
    HelloWorldApp() { 
        HelloWorldMainScreen mainScreen = new HelloWorldMainScreen();
        pushScreen(mainScreen);
}
        public static void main(String[] args){
            HelloWorldApp app = new HelloWorldApp();
            app.enterEventDispatcher();
     }     
}   



\\ HelloWorldMainScreen.java
package com.beginningblackberry.helloworld;

import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.component.LabelField;

class HelloWorldMainScreen {
    HelloWorldMainScreen() {
        LabelField labelField = new LabelField("Hello World");
        add(labelField);
        }
} 

1 个答案:

答案 0 :(得分:1)

HelloWorldMainScreen中您可能需要扩展其他类或需要提供add()的实现