public class MainActivity extends Activity {
private String md5(String in) {
MessageDigest digest;
try {
digest = MessageDigest.getInstance("MD5");
digest.reset();
digest.update(in.getBytes());
byte[] a = digest.digest();
int len = a.length;
StringBuilder sb = new StringBuilder(len << 1);
for (int i = 0; i < len; i++) {
sb.append(Character.forDigit((a[i] & 0xf0) >> 4, 16));
sb.append(Character.forDigit(a[i] & 0x0f, 16));
}
return sb.toString();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button) findViewById(R.id.button1);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
EditText text = (EditText) findViewById(R.id.editText1);
EditText text1 = (EditText) findViewById(R.id.editText2);
String userid = text.getText().toString();
String pass = text1.getText().toString();
Toast.makeText(
MainActivity.this,
"Entered " + userid + " and password entered is "
+ pass, Toast.LENGTH_LONG).show();
pass = md5(pass + "@string/salt");
Toast.makeText(
MainActivity.this,
"Password after adding a salt and md5 hashing is now equal to "
+ pass, Toast.LENGTH_LONG).show();
/* This Line */DBAdapter db = new DBAdapter(this); // This Line.
db.open();
Cursor c = db.getPasswordForUserName(userid);
if (c.moveToFirst()) {
if (c.getString(1) == pass) {
Toast.makeText(MainActivity.this,
"Authentication Succeded", Toast.LENGTH_SHORT)
.show();
// proceed
} else {
Toast.makeText(MainActivity.this, "@string/AuthFail",
Toast.LENGTH_SHORT).show();
// AuthFailure
}
} else {
Toast.makeText(MainActivity.this, "@string/UserNotFound",
Toast.LENGTH_SHORT).show();
// where to from here
}
}
});
}
}
我对Android编程非常陌生。所以我从很多地方采集了代码片段,然后将它们合并。错误:xyz类的构造函数未定义
基本上我想要做的是查询当地的SQLite数据库现有的价值UserName
和Password
+ salt(with md5 hash)
。
所以我复制了一些代码来创建一个数据库帮助类(DBAdapter
),它具有处理数据库的基本方法。
现在的问题是在MainActivity.java
文件中。标记为“此行”的行在代码中给出了错误构造函数DBAdapter(new View.OnClickListener(){})未定义。我不知道这是什么意思。我应该怎么做才能使它工作?
我会建议任何人尝试学习Android来首先学习Java。具体来说,您正在使用一个询问DBAdapter来接受一个View.OnClickListener作为参数。 – 2013-03-07 23:19:18