简单记录下安卓环境的搭建和第一个安卓程序的破解

         private EditText edit_userName;
        private EditText edit_sn;
        private Button btn_register; 
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            setTitle(R.string.unregister);  //模拟程序未注册
            edit_userName = (EditText) findViewById(R.id.edit_username);
            edit_sn = (EditText) findViewById(R.id.edit_passwd);
            btn_register = (Button) findViewById(R.id.buttonRG);
            
            //对于Button的点击事件的监听
            btn_register.setOnClickListener(new OnClickListener() {
                
                public void onClick(View v) {
                    if (!checkSN(edit_userName.getText().toString().trim(), 
                            edit_sn.getText().toString().trim())) {
                        Toast.makeText(MainActivity.this,       //弹出无效用户名或注册码提示
                                R.string.unsuccessed, Toast.LENGTH_SHORT).show();
                    } else {
                        Toast.makeText(MainActivity.this,       //弹出注册成功提示
                                R.string.successed, Toast.LENGTH_SHORT).show();
                        btn_register.setEnabled(false);
                        setTitle(R.string.registered);  //模拟程序已注册
                    }                
                }
            });    
        }

private boolean checkSN(String userName,String sn)
    {
        try{
            if((userName==null)||(userName.length()==0))
                return false;
            if((sn==null)||(sn.length()==0))
                return false;
            MessageDigest digest = MessageDigest.getInstance("MD5");
            digest.reset();
            digest.update(userName.getBytes());
            byte[] bytes = digest.digest(); //采用MD5对用户名进行HASH
            String hexstr = toHexString(bytes, ""); //将计算结果转化成字符串
            StringBuilder sb = new StringBuilder();
            for(int i=0;i<hexstr.length();i+=2)
            {
                sb.append(hexstr.charAt(i));
            }
            String userSN = sb.toString();//计算出的SN
            if(!userSN.equalsIgnoreCase(sn))//比较注册码是否正确
                return false;
            
            
        }
        catch (NoSuchAlgorithmException e)
        {
            e.printStackTrace();
            return false;
        }
        return false;
        
    }
    
       private static String toHexString(byte[] bytes, String separator) {
            StringBuilder hexString = new StringBuilder();
            for (byte b : bytes) {
                String hex = Integer.toHexString(0xFF & b);
                if(hex.length() == 1){
                    hexString.append(‘0‘);
                }
                hexString.append(hex).append(separator);
            }
            return hexString.toString();
        }
        

如果不合法则不跳转 提示不成功
 .line 40
    # invokes: Lcom/example/crackmemz021/MainActivity;->checkSN(Ljava/lang/String;Ljava/lang/String;)Z
    invoke-static {v0, v1, v2}, Lcom/example/crackmemz021/MainActivity;->access$2(Lcom/example/crackmemz021/MainActivity;Ljava/lang/String;Ljava/lang/String;)Z   #检查注册码是否合法

    move-result v0

    .line 41
    if-nez v0, :cond_0  #如果结果不为0 ，就跳转到cond_0标号处

    .line 42
    iget-object v0, p0, Lcom/example/crackmemz021/MainActivity$1;->this$0:Lcom/example/crackmemz021/MainActivity;

    .line 43
    const v1, 0x7f050004    #unsuccessed字符串

    .line 42
    invoke-static {v0, v1, v3}, Landroid/widget/Toast;->makeText(Landroid/content/Context;II)Landroid/widget/Toast;



成功则跳转至cond_0，显示成功
  .line 45
    :cond_0
    iget-object v0, p0, Lcom/example/crackmemz021/MainActivity$1;->this$0:Lcom/example/crackmemz021/MainActivity;

    .line 46
    const v1, 0x7f050005 #successed 字符串  代表成功

    .line 45
    invoke-static {v0, v1, v3}, Landroid/widget/Toast;->makeText(Landroid/content/Context;II)Landroid/widget/Toast;

    move-result-object v0

    .line 46
    invoke-virtual {v0}, Landroid/widget/Toast;->show()V

    .line 47
    iget-object v0, p0, Lcom/example/crackmemz021/MainActivity$1;->this$0:Lcom/example/crackmemz021/MainActivity;

    # getter for: Lcom/example/crackmemz021/MainActivity;->btn_register:Landroid/widget/Button;
    invoke-static {v0}, Lcom/example/crackmemz021/MainActivity;->access$3(Lcom/example/crackmemz021/MainActivity;)Landroid/widget/Button;

    move-result-object v0

    invoke-virtual {v0, v3}, Landroid/widget/Button;->setEnabled(Z)V  #设置注册按钮不可用

    .line 48
    iget-object v0, p0, Lcom/example/crackmemz021/MainActivity$1;->this$0:Lcom/example/crackmemz021/MainActivity;

    const v1, 0x7f050003  #registered字符串 模拟注册成功

    invoke-virtual {v0, v1}, Lcom/example/crackmemz021/MainActivity;->setTitle(I)V

    goto :goto_0