static void Dalvik_java_lang_VMClassLoader_defineClass(const u4* args,JValue* pResult){ 
  Object* loader = (Object*) args[0]; 
  StringObject* nameObj = (StringObject*) args[1]; 
  const u1* data = (const u1*) args[2]; 
  int offset = args[3]; 
  int len = args[4]; 
  Object* pd = (Object*) args[5]; 
  char* name = NULL; 
  name = dvmCreateCstrFromString(nameObj); 
  LOGE("ERROR: defineClass(%p, %s, %p, %d, %d, %p)n",loader, name, data, offset, len, pd); 
  dvmThrowException("Ljava/lang/UnsupportedOperationException;","can't load this type of class file"); 
  free(name); 
  RETURN_VOID(); 
} 

/* --this doesn't work in current version of Dalvik-- 
  if (data != null) { 
    System.out.println("--- Found class " + name 
      + " in zip[" + i + "] '" + mZips[i].getName() + "'"); 
    int dotIndex = name.lastIndexOf('.'); 
    if (dotIndex != -1) { 
      String packageName = name.substring(0, dotIndex); 
      synchronized (this) { 
        Package packageObj = getPackage(packageName); 
        if (packageObj == null) { 
          definePackage(packageName, null, null, 
              null, null, null, null, null); 
        } 
      } 
    } 
    return defineClass(name, data, 0, data.length); 
  } 
*/ 

protected Class<?> loadClass(String className, boolean resolve) throws ClassNotFoundException { 
Class<?> clazz = findLoadedClass(className); 
  if (clazz == null) { 
    try { 
      clazz = parent.loadClass(className, false); 
    } catch (ClassNotFoundException e) { 
      // Don't want to see this. 
    } 
    if (clazz == null) { 
      clazz = findClass(className); 
    } 
  } 
  return clazz; 
} 

public Class loadClass(String name, ClassLoader loader) { 
    String slashName = name.replace('.', '/'); 
    return loadClassBinaryName(slashName, loader); 
} 

package com.dynamic.interfaces; 
import android.app.Activity; 
/** 
 * 动态加载类的接口 
 */ 
public interface IDynamic { 
  /**初始化方法*/ 
  public void init(Activity activity); 
  /**自定义方法*/ 
  public void showBanner(); 
  public void showDialog(); 
  public void showFullScreen(); 
  public void showAppWall(); 
  /**销毁方法*/ 
  public void destory(); 
} 

package com.dynamic.impl; 
 
import android.app.Activity; 
import android.widget.Toast; 
 
import com.dynamic.interfaces.IDynamic; 
 
/** 
 * 动态类的实现 
 * 
 */ 
public class Dynamic implements IDynamic{ 
 
  private Activity mActivity; 
   
  @Override 
  public void init(Activity activity) { 
    mActivity = activity; 
  } 
   
  @Override 
  public void showBanner() { 
    Toast.makeText(mActivity, "我是ShowBannber方法", 1500).show(); 
  } 
 
  @Override 
  public void showDialog() { 
    Toast.makeText(mActivity, "我是ShowDialog方法", 1500).show(); 
  } 
 
  @Override 
  public void showFullScreen() { 
    Toast.makeText(mActivity, "我是ShowFullScreen方法", 1500).show(); 
  } 
 
  @Override 
  public void showAppWall() { 
    Toast.makeText(mActivity, "我是ShowAppWall方法", 1500).show(); 
  } 
 
  @Override 
  public void destory() { 
  } 
 
} 

package com.jiangwei.demo; 
 
import java.io.File; 
import java.util.List; 
 
import android.app.Activity; 
import android.content.Intent; 
import android.content.pm.ActivityInfo; 
import android.content.pm.PackageManager; 
import android.content.pm.ResolveInfo; 
import android.os.Bundle; 
import android.os.Environment; 
import android.view.View; 
import android.widget.Button; 
import android.widget.Toast; 
 
import com.dynamic.interfaces.IDynamic; 
 
import dalvik.system.DexClassLoader; 
import dalvik.system.PathClassLoader; 
 
public class AndroidDynamicLoadClassActivity extends Activity { 
   
  //动态类加载接口 
  private IDynamic lib; 
   
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    //初始化组件 
    Button showBannerBtn = (Button) findViewById(R.id.show_banner_btn); 
    Button showDialogBtn = (Button) findViewById(R.id.show_dialog_btn); 
    Button showFullScreenBtn = (Button) findViewById(R.id.show_fullscreen_btn); 
    Button showAppWallBtn = (Button) findViewById(R.id.show_appwall_btn); 
    /**使用DexClassLoader方式加载类*/ 
    //dex压缩文件的路径(可以是apk,jar,zip格式) 
    String dexPath = Environment.getExternalStorageDirectory().toString() + File.separator + "Dynamic.apk"; 
    //dex解压释放后的目录 
    //String dexOutputDir = getApplicationInfo().dataDir; 
    String dexOutputDirs = Environment.getExternalStorageDirectory().toString(); 
    //定义DexClassLoader 
    //第一个参数：是dex压缩文件的路径 
    //第二个参数：是dex解压缩后存放的目录 
    //第三个参数：是C/C++依赖的本地库文件目录,可以为null 
    //第四个参数：是上一级的类加载器 
    DexClassLoader cl = new DexClassLoader(dexPath,dexOutputDirs,null,getClassLoader()); 
     
    /**使用PathClassLoader方法加载类*/ 
    //创建一个意图，用来找到指定的apk：这里的"com.dynamic.impl是指定apk中在AndroidMainfest.xml文件中定义的<action name="com.dynamic.impl"/>  
    Intent intent = new Intent("com.dynamic.impl", null);  
    //获得包管理器  
    PackageManager pm = getPackageManager();  
    List<ResolveInfo> resolveinfoes = pm.queryIntentActivities(intent, 0);  
    //获得指定的activity的信息  
    ActivityInfo actInfo = resolveinfoes.get(0).activityInfo;  
    //获得apk的目录或者jar的目录  
    String apkPath = actInfo.applicationInfo.sourceDir;  
    //native代码的目录  
    String libPath = actInfo.applicationInfo.nativeLibraryDir;  
    //创建类加载器，把dex加载到虚拟机中  
    //第一个参数：是指定apk安装的路径，这个路径要注意只能是通过actInfo.applicationInfo.sourceDir来获取 
    //第二个参数：是C/C++依赖的本地库文件目录,可以为null 
    //第三个参数：是上一级的类加载器 
    PathClassLoader pcl = new PathClassLoader(apkPath,libPath,this.getClassLoader()); 
    //加载类 
    try { 
      //com.dynamic.impl.Dynamic是动态类名 
      //使用DexClassLoader加载类 
      //Class libProviderClazz = cl.loadClass("com.dynamic.impl.Dynamic"); 
      //使用PathClassLoader加载类 
      Class libProviderClazz = pcl.loadClass("com.dynamic.impl.Dynamic"); 
      lib = (IDynamic)libProviderClazz.newInstance(); 
      if(lib != null){ 
        lib.init(AndroidDynamicLoadClassActivity.this); 
      } 
    } catch (Exception exception) { 
      exception.printStackTrace(); 
    } 
    /**下面分别调用动态类中的方法*/ 
    showBannerBtn.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
        if(lib != null){ 
          lib.showBanner(); 
        }else{ 
          Toast.makeText(getApplicationContext(), "类加载失败", 1500).show(); 
        } 
      } 
    }); 
    showDialogBtn.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
        if(lib != null){ 
          lib.showDialog(); 
        }else{ 
          Toast.makeText(getApplicationContext(), "类加载失败", 1500).show(); 
        } 
      } 
    }); 
    showFullScreenBtn.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
        if(lib != null){ 
          lib.showFullScreen(); 
        }else{ 
          Toast.makeText(getApplicationContext(), "类加载失败", 1500).show(); 
        } 
      } 
    }); 
    showAppWallBtn.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
        if(lib != null){ 
          lib.showAppWall(); 
        }else{ 
          Toast.makeText(getApplicationContext(), "类加载失败", 1500).show(); 
        } 
      } 
    }); 
  } 
} 

DexClassLoader方式加载:
//定义DexClassLoader 
//第一个参数：是dex压缩文件的路径 
//第二个参数：是dex解压缩后存放的目录 
//第三个参数：是C/C++依赖的本地库文件目录,可以为null 
//第四个参数：是上一级的类加载器 
DexClassLoader cl = new DexClassLoader(dexPath,dexOutputDirs,null,getClassLoader()); 

//获得apk的目录或者jar的目录  
String apkPath = actInfo.applicationInfo.sourceDir;  

//创建一个意图，用来找到指定的apk：这里的"com.dynamic.impl是指定apk中在AndroidMainfest.xml文件中定义的<action name="com.dynamic.impl"/>  
Intent intent = new Intent("com.dynamic.impl", null);