Jni调用不同时使用swing API [英] Jni call not simultaneously working with swing API

问题描述

你好，



我想从Netbeans的java类中调用Jni funktion，但只有当我关闭Swing Gui时才会执行Jni funktion。



运行应用程序时，

 Hello World from C 

如何显示？





任何解决方案？



我尝试过： < br $>

 * @author peter 
 * / 
公共类Linux_Kamera_AWT扩展java.awt.Frame {
 
 / ** 
 *创建新表单Linux_Kamera_AWT 
 * / 
 public Linux_Kamera_AWT（）{
 initComponents（）; 
} 
 
 / ** 
 *从构造函数中调用此方法以初始化表单。 
 *警告：请勿修改此代码。此方法的内容始终由表单编辑器重新生成
 *。 
 * / 
 //< editor-fold defaultstate =collapseddesc =Generated Code> 
 private void initComponents（）{
 
 jButton1 = new javax.swing.JButton（）; 
 Start_JNI = new javax.swing.JButton（）; 
 jButton3 = new javax.swing.JButton（）; 
 
 jButton1.setText（jButton1）; 
 
 addWindowListener（new java.awt.event.WindowAdapter（）{
 public void windowClosing（java.awt.event.WindowEvent evt）{
 exitForm（evt）; 
} 
}）; 
 
 Start_JNI.setText（jButton2）; 
 Start_JNI.addActionListener（new java.awt.event.ActionListener（）{
 public void actionPerformed（java.awt.event.ActionEvent evt）{
 Start_JNIActionPerformed（evt）; 
 } 
}）; 
 add（Start_JNI，java.awt.BorderLayout.NORTH）; 
 
 jButton3.setText（jButton3）; 
 add（jButton3，java.awt.BorderLayout.WEST）; 
 
 pack（）; 
} //< / editor-fold> 
 
 / ** 
 *退出应用程序
 * / 
 private void exitForm（java.awt.event.WindowEvent evt）{
 System.exit （0）; 
} 
 
 private void Start_JNIActionPerformed（java.awt.event.ActionEvent evt）{
 // TODO在这里添加你的处理代码：
 
 callNativeFunction（ ）; 
 JNIServer.nativePrint（）; 
} 
 
 / ** 
 * @param args命令行参数
 * / 
 public static void main（String args []）{
 //JNIServer.nativePrint（）; 
 java.awt.EventQueue.invokeLater（new Runnable（）{
 public void run（）{
 new Linux_Kamera_AWT（）。setVisible（true）; 
} 
 }）; 
} 
 
 
 private static void callNativeFunction（）{
 Thread nativeFunctionThread = new Thread（new Runnable（）{
 @Override 
 public void run（）{
 System.out.println（Test.run  - 在调用hello之前。）; 
 new JNIServer（）。nativePrint（）; //其中hello是本机方法
 System.out.println（Test.run  - 在调用hello之后。）; 
} 
}）; 
 
 nativeFunctionThread.start（）; 
} 
 
 
 //变量声明 - 不要修改
 private javax.swing.JButton Start_JNI; 
 private javax.swing.JButton jButton1; 
 private javax.swing.JButton jButton3; 
 //变量结束声明
} 

C源文件：

 // *要更改此许可证标题，请在项目属性中选择许可证标题。 
 #include< jni.h> 
 #include< stdio.h> 
 #includeLinux_Kamera.h
 
 JNIEXPORT void JNICALL Java_humer_peter_JNIServer_nativePrint 
（JNIEnv * env，jobject obj）
 {
 
 printf（ \ nHello World from C\ n）; 
 
} 

公共类JNIServer {
 public native void hello （）; 
 
 static {
 System.out.println（Inload library）; 
 System.loadLibrary（JNI_Lib）; 
} 
} 

C-Headerfile：

 / *不要编辑这个文件 - 它是机器生成的* / 
 #include< jni.h> 
 / *班级humer_peter_JNIServer * / 
 
 #ifndef _Included_humer_peter_JNIServer 
 #define _Included_humer_peter_JNIServer 
 #ifdef __cplusplus 
 externC{
 #endif 
 / * 
 *类：humer_peter_JNIServer 
 *方法：nativePrint 
 *签名:(）V 
 * / 
 JNIEXPORT void JNICALL Java_humer_peter_JNIServer_nativePrint 
（JNIEnv *，jobject）; 
 
 #ifdef __cplusplus 
} 
 #endif 
 #endif 

解决方案

< blockquote>您正在从基于窗口的应用程序调用printf。但printf使用AWT中不存在的控制台。

Hello,

I want to call a Jni funktion from a java class in Netbeans, but the Jni funktion is only performed, when I close the Swing Gui.

How can the

Hello World from C

displayed at ones when running the application?


Any solutions?

What I have tried:

* @author peter
 */
public class Linux_Kamera_AWT extends java.awt.Frame {

    /**
     * Creates new form Linux_Kamera_AWT
     */
    public Linux_Kamera_AWT() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jButton1 = new javax.swing.JButton();
        Start_JNI = new javax.swing.JButton();
        jButton3 = new javax.swing.JButton();

        jButton1.setText("jButton1");

        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
            }
        });

        Start_JNI.setText("jButton2");
        Start_JNI.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                Start_JNIActionPerformed(evt);
            }
        });
        add(Start_JNI, java.awt.BorderLayout.NORTH);

        jButton3.setText("jButton3");
        add(jButton3, java.awt.BorderLayout.WEST);

        pack();
    }// </editor-fold>                        

    /**
     * Exit the Application
     */
    private void exitForm(java.awt.event.WindowEvent evt) {                          
        System.exit(0);
    }                         

    private void Start_JNIActionPerformed(java.awt.event.ActionEvent evt) {                                          
        // TODO add your handling code here:
        
        callNativeFunction();
        JNIServer.nativePrint();
    }                                         

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        //JNIServer.nativePrint();
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Linux_Kamera_AWT().setVisible(true);
            }
        });
    }
    
    
    private static void callNativeFunction() {
        Thread nativeFunctionThread = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("Test.run - before calling hello.");
                new JNIServer().nativePrint();  // where hello is native method
                System.out.println("Test.run - after calling hello.");
            }
        });

        nativeFunctionThread.start();
    }


    // Variables declaration - do not modify                     
    private javax.swing.JButton Start_JNI;
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton3;
    // End of variables declaration                   
}

C-Source File:

// * To change this license header, choose License Headers in Project Properties.
#include <jni.h>
#include <stdio.h>
#include "Linux_Kamera.h"

JNIEXPORT void JNICALL Java_humer_peter_JNIServer_nativePrint
        (JNIEnv *env, jobject obj)
{

    printf("\nHello World from C\n");

}

public class JNIServer {
    public native void hello();

    static {  
        System.out.println("Inload library");
        System.loadLibrary("JNI_Lib");
    }  
}

C-Headerfile:

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class humer_peter_JNIServer */

#ifndef _Included_humer_peter_JNIServer
#define _Included_humer_peter_JNIServer
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     humer_peter_JNIServer
 * Method:    nativePrint
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_humer_peter_JNIServer_nativePrint
  (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

解决方案

You are calling printf from a window based application. But printf uses the console which does not exist in AWT.

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