Question

我正在尝试使用Java中的CodenameOne运行一个简单的Hello World程序。我正在尝试向应用添加按钮。我收到两个编译器错误，它们都：
java：找不到符号
符号：班级按钮

代码如下：

//ORIGIONAL CODE
package CodenameOneHelloWorld;


import static com.codename1.ui.CN.*;
import com.codename1.ui.Display;
import com.codename1.ui.Form;
import com.codename1.ui.Dialog;
import com.codename1.ui.Label;
import com.codename1.ui.plaf.UIManager;
import com.codename1.ui.util.Resources;
import com.codename1.io.Log;
import com.codename1.ui.Toolbar;
import java.io.IOException;
import com.codename1.ui.layouts.BoxLayout;
import com.codename1.io.NetworkEvent;

/**
 * This file was generated by <a href="https://www.codenameone.com/">Codename One</a> for the purpose 
 * of building native mobile applications using Java.
 */
public class MyApplication {

    private Form current;
    private Resources theme;

    public void init(Object context) {
        // use two network threads instead of one
        updateNetworkThreadCount(2);

        theme = UIManager.initFirstTheme("/theme");

        // Enable Toolbar on all Forms by default
        Toolbar.setGlobalToolbar(true);

        // Pro only feature
        Log.bindCrashProtection(true);

        addNetworkErrorListener(err -> {
            // prevent the event from propagating
            err.consume();
            if(err.getError() != null) {
                Log.e(err.getError());
            }
            Log.sendLogAsync();
            Dialog.show("Connection Error", "There was a networking error in the connection to " + err.getConnectionRequest().getUrl(), "OK", null);
        });        
    }
    
    public void start() {
        if(current != null){
            current.show();
            return;
        }
        Form hi = new Form("Hi World", BoxLayout.y());
        hi.add(new Label("Hi World"));
        Button b = new Button("Show Dialog"); // LINE HAND-TYPED ACCORDING TO TUTORIAL
        hi.add(b); // LINE HAND-TYPED ACCORDING TO TUTORIAL
        b.addActionListener((e) -> Dialog.show("Dialog Title", "Hi", "OK", null)); // LINE HAND-TYPED ACCORDING TO TUTORIAL
        hi.show();
    }

    public void stop() {
        current = getCurrentForm();
        if(current instanceof Dialog) {
            ((Dialog)current).dispose();
            current = getCurrentForm();
        }
    }
    
    public void destroy() {
    }

}

按照编译器的说明进行操作后，我将获得以下新代码：

// CODE MODIFIED BY SUGGESTION FROM COMPILER
package CodenameOneHelloWorld;


import static com.codename1.ui.CN.*;
import com.codename1.ui.Display;
import com.codename1.ui.Form;
import com.codename1.ui.Dialog;
import com.codename1.ui.Label;
import com.codename1.ui.plaf.UIManager;
import com.codename1.ui.util.Resources;
import com.codename1.io.Log;
import com.codename1.ui.Toolbar;

import java.awt.*;  // ADDED IMPORT LINE
import java.io.IOException;
import com.codename1.ui.layouts.BoxLayout;
import com.codename1.io.NetworkEvent;

/**
 * This file was generated by <a href="https://www.codenameone.com/">Codename One</a> for the purpose 
 * of building native mobile applications using Java.
 */
public class MyApplication {

    private Form current;
    private Resources theme;

    public void init(Object context) {
        // use two network threads instead of one
        updateNetworkThreadCount(2);

        theme = UIManager.initFirstTheme("/theme");

        // Enable Toolbar on all Forms by default
        Toolbar.setGlobalToolbar(true);

        // Pro only feature
        Log.bindCrashProtection(true);

        addNetworkErrorListener(err -> {
            // prevent the event from propagating
            err.consume();
            if(err.getError() != null) {
                Log.e(err.getError());
            }
            Log.sendLogAsync();
            Dialog.show("Connection Error", "There was a networking error in the connection to " + err.getConnectionRequest().getUrl(), "OK", null);
        });        
    }
    
    public void start() {
        if(current != null){
            current.show();
            return;
        }
        Form hi = new Form("Hi World", BoxLayout.y());
        hi.add(new Label("Hi World"));
        Button b = new Button("Show Dialog");
        hi.add(String.valueOf(b)); // CHANGED LINE AS SUGGESTED BY COMPILER
        b.addActionListener((e) -> Dialog.show("Dialog Title", "Hi", "OK", null));
        hi.show();
    }

    public void stop() {
        current = getCurrentForm();
        if(current instanceof Dialog) {
            ((Dialog)current).dispose();
            current = getCurrentForm();
        }
    }
    
    public void destroy() {
    }

}

新代码编译干净，但是在模拟器中运行时，应用程序显示错误消息而不是按钮。

有人对如何使按钮在Hello World应用程序中正确显示有任何想法吗？

Answer 1

AWT无法在这里工作。当您尝试导入时，IDE提供了多个选项，而另一个选项应为import com.codename1.ui.Button;。您可以在JavaDocs中查看受支持的类的完整列表：https://www.codenameone.com/javadoc/

Hello World CodenameOne Java程序中的错误

1 个答案: