public void loadApkClass(String apkPath, Context context) {
//app路徑下的資料夾名稱
File dexOutputDir = context.getDir("dex", 0);
//被載入的Class
String className = "com.mz.testapk.TestClass";
    DexClassLoader classLoader = new DexClassLoader(apkPath, dexOutputDir.getAbsolutePath(), null, getClassLoader());
try {
        Class mLoadClass = classLoader.loadClass(className);
//
 
預設構造方法
Constructor constructor = mLoadClass.getConstructor(new Class[]{});
        Object testClass = constructor.newInstance(new Object[]{});
//TestClass 中的getStr方法
Method getStr = mLoadClass.getDeclaredMethod("getStr", null);
        getStr.setAccessible(true);
        Object money = getStr.invoke(testClass, null
 
);
        Toast.makeText(this, money.toString(), Toast.LENGTH_LONG).show();
    } catch (Exception e) {
        e.printStackTrace();
    }

}

// TestClass程式碼

package com.mz.testapk;

public class TestClass {
public String getStr() {
return "TestClassStr";
    }
}