注意该.so库指的是android平台的,非一般linux、unix平台;
1、现有库libcom_ycan_testLib.so
2、新建android项目TestLib2
3、添加新类:
类名:testLib
包路径:参考现有库名,应为com.ycan
4、在新类中声明库的本地方法,如下:
package com.ycan;  public class PDFLib {  public native int add (int a, int b);  public native int sub (int a, int b);  
}  
5、然后把库文件拷贝到如下目录:
 \workspace\TestLib2\libs\armeabi
 
似乎必须是这个路径吧,我刚开始没有armeabi目录,结果运行出错,最后自己新建了一个这样的目录,才ok了。
6、在主类中调用库接口,我的库是做加减法的,基本调用代码如下:
package com.testlib2;  import com.ycan.testLib;  import android.os.Bundle;  
import android.app.Activity;  
import android.view.Menu;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.widget.Button;  
import android.widget.EditText;  
import android.widget.Toast;  public class MainActivity extends Activity {  private Button btnAdd;  private Button btnSub;  private EditText num1;  private EditText num2;  private EditText result;  private int a,b,rlt;  private testLib lib = new testLib();  @Override  public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  btnAdd = (Button)findViewById(R.id.button_add);  btnSub = (Button)findViewById(R.id.button_sub);  num1 = (EditText)findViewById(R.id.num1);  num2 = (EditText)findViewById(R.id.num2);  result = (EditText)findViewById(R.id.num3);  btnAdd.setOnClickListener(new OnClickListener(){  @Override  public void onClick(View v) {  // TODO Auto-generated method stub  String strnum1 = num1.getText().toString();  a = Integer.parseInt(strnum1);  String strnum2 = num2.getText().toString();  b = Integer.parseInt(strnum2);  rlt = lib.add(a,b);  Dostop(rlt);  }  });  btnSub.setOnClickListener(new OnClickListener()  {  @Override  public void onClick(View v) {  // TODO Auto-generated method stub  String strnum1 = num1.getText().toString();  a = Integer.parseInt(strnum1);  String strnum2 = num2.getText().toString();  b = Integer.parseInt(strnum2);  rlt = lib.sub(a,b);  Dostop(rlt);  }  }  );  }  static {          System.loadLibrary("com_ycan_testLib");      }  private void Dostop(int number){  Toast.makeText(this, ""+number, 8).show();//显示8秒  String x=Integer.toString(rlt);   result.setText(x);  }  @Override  public boolean onCreateOptionsMenu(Menu menu) {  getMenuInflater().inflate(R.menu.activity_main, menu);  return true;  }  
}