CODEWITHSUNDEEP
androidlinuxandroid-emulatorandroid-ndk
kaiwii ho
kaiwii ho

Reputation: 1407

android ndk programming:socket

i am new to ndk programming and have a try to make a project. My project's purpose is to build a client that i can use the button's listener to call the native method of socket programming.And,there is server running already in the android. And everything runs okay when i build it and export it as the apk.But,unfortunately,after i install the apk and try to run it.The system prompt that:Unfortunately,the NativeSocket has stopped. And the following is my code: NativeSocketActivity.java:

package gz.kaiwii;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class NativeSocketActivity extends Activity {
    /** Called when the activity is first created. */
    final Button button = (Button) findViewById(R.id.button1);
    /*static*/
    static{
        System.loadLibrary("NativeSocket");
    }
    /*native method stuff*/
    static native void start();
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        button.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                start();

            }
        });
    }
}

Android.mk:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := NativeSocket
### Add all source file names to be included in lib separated by a whitespace
LOCAL_SRC_FILES := NativeSocket.c

include $(BUILD_SHARED_LIBRARY)

NativeSocket.c:

#include <string.h>
#include <jni.h>
/*  Make the necessary includes and set up the variables.  */

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>

JNIEXPORT void JNICALL Java_gz_kaiwii_NativeSocketActivity_start
  (JNIEnv *env, jclass jclss)
{
    int sockfd;
    int len;
    struct sockaddr_un address;
    int result;
    char ch = 'A';

/*  Create a socket for the client.  */

    sockfd = socket(AF_UNIX, SOCK_STREAM, 0);

/*  Name the socket, as agreed with the server.  */

    address.sun_family = AF_UNIX;
    strcpy(address.sun_path, "server_socket");
    len = sizeof(address);

/*  Now connect our socket to the server's socket.  */

    result = connect(sockfd, (struct sockaddr *)&address, len);
/*
    if(result == -1) {
        perror("oops: client1");
        exit(1);
    }
    */

/*  We can now read/write via sockfd.  */

    write(sockfd, &ch, 1);
    read(sockfd, &ch, 1);
    /*
    printf("char from server = %c\n", ch);
    */
    close(sockfd);
}

Upvotes: 0

Views: 6701

Answers (2)

nurisezgin
nurisezgin

Reputation: 1570

You create button reference in onCreate method after setContentView ndk error never gives force close only shutdown vm.

Upvotes: 1

Mārtiņš Možeiko
Mārtiņš Možeiko

Reputation: 12927

I'm not sure if this is needed in this case - but have you tried adding <uses-permission android:name="android.permission.INTERNET" /> to your AndroidManifest.xml file?

Also what is the exact error/exception and the call stack on crash? You can view it in DDMS or with adb logcat on commandline.

Also - verify return values from C functions and log appropriate error message. Use <android/log.h> for that.

Upvotes: 0

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