我想记录用户并保存登录的用户名，并将其作为Toast或TextView显示在MainActivity中。
以下是我目前的代码：
Session.java
public class Session {
SharedPreferences sharepref;
SharedPreferences.Editor editor;
Context context;
public Session(Context context){
this.context = context;
sharepref = context.getSharedPreferences("mypref", Context.MODE_PRIVATE);
editor = sharepref.edit();
editor.commit();
}
public void setLoggedin(boolean loggedin){
editor.putBoolean("loggedInmode",loggedin);
editor.commit();
}
public boolean loggedin(){
return sharepref.getBoolean("loggedInmode", false);
}
}
LoginActivity.java
public class LoginActivity extends AppCompatActivity{
//private Button login, register;
private EditText etUser, etPass;
private DatabaseHelper dbHelper;
private Session session;
private static final String SALT = "50C7BC9D21";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
dbHelper = new DatabaseHelper(this);
session = new Session(this);
etUser = (EditText)findViewById(R.id.etUsername);
etPass = (EditText)findViewById(R.id.etPassword);
//login = (Button)findViewById(R.id.btnLogin);
//register = (Button)findViewById(R.id.btnRegister);
//login.setOnClickListener(this);
//register.setOnClickListener(this);
if(session.loggedin()){
startActivity(new Intent(LoginActivity.this,MainActivity.class));
finish();
}
}
/*
@Override
public void onClick(View v) {
switch(v.getId()){
case R.id.btnLogin:
login();
break;
case R.id.btnRegister:
//register();
startActivity(new Intent(LoginActivity.this,RegisterActivity.class));
break;
default:
}
}*/
/**
* METHOD THAT WILL BE EXECUTED ONCE THE EXIT BUTTON IS CLICKED
* ITS SOLO PURPOSE IS TO TERMINATE THE APPLICATION.
* */
public void exitApp(View v){
android.os.Process.killProcess(android.os.Process.myPid());
System.exit(1);
}
/**
* METHOD THAT WILL BE EXECUTED ONCE THE REGISTER BUTTON IS CLICKED
* ITS SOLO PURPOSE IS TO TAKE THE USER TO THE REGISTER WINDOW.
* */
public void newUser(View v){
startActivity(new Intent(LoginActivity.this,RegisterActivity.class));
}
/**
* METHOD THAT WILL BE EXECUTED ONCE THE LOGIN BUTTON IS CLICKED
* ITS SOLO PURPOSE IT TO COMPARE THE INFORMATION ENTERED IN THE EDITTEXT BOXES
* AND SEE IF ITS EQUAL WITH THE INFORMATION STORED IN THE DATABASE.
* */
public void loginUser(View v){
String user = etUser.getText().toString();
String pass = etPass.getText().toString();
String passwordToHash = pass;
String generatedPassword = null;
String finalpw = null;
try {
// Create MessageDigest instance for MD5
MessageDigest md = MessageDigest.getInstance("SHA1");
//Add password bytes to digest
md.update(passwordToHash.getBytes());
//Get the hash's bytes
byte[] bytes = md.digest();
//This bytes[] has bytes in decimal format;
//Convert it to hexadecimal format
StringBuilder sb = new StringBuilder();
for(int i=0; i< bytes.length ;i++)
{
sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));
}
//Get complete hashed password in hex format
generatedPassword = sb.toString();
finalpw = generatedPassword + SALT;
Toast.makeText(this, finalpw, Toast.LENGTH_SHORT).show();
}
catch (NoSuchAlgorithmException e)
{
e.printStackTrace();
}
System.out.println(generatedPassword);
//THIS WAS FIXED AROUND BECAUSE THE OTHER WAY FETCHING AND EQUALLING WITH DB AN USER COULD PASS BY WITHOUT REGESTERING.
if(dbHelper.getUser(user,finalpw)){
session.setLoggedin(true);
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}else{
Toast.makeText(getApplicationContext(), R.string.wrong_info,Toast.LENGTH_SHORT).show();
}
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
private static final int REQUEST_CODE_ADD_CONTACT = 1;
private Session session;
//private TaskAdapter taskAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
session = new Session(this);
if (!session.loggedin()) {
logout();
}
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CODE_ADD_CONTACT) {
if (resultCode == RESULT_OK) {
}
}
}
public void logout() {
session.setLoggedin(false);
finish();
startActivity(new Intent(MainActivity.this, LoginActivity.class));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_logout) {
logout();
return true;
}
return super.onOptionsItemSelected(item);
}
}
重复想要记录用户登录信息。具体来说，我想保存登录的用户名，并将其作为Toast或TextView显示在MainActivity中。
对于我所阅读的内容，我尝试使用intent.putextra并使用bundle，它将在首次安装时运行但之后会使应用程序崩溃，所以我尝试使用sharedpreference并创建了一个会话。
我在这里有点受阻。如何在会话中保存每个不同的用户，然后在MainActivity中显示其用户名？
很抱歉，如果我的第一篇帖子出错了。
答案 0 :(得分：0)
您可以制作另一个可以放入SharedPref的参数。例如，在你的set loggin中：
#1067 - Invalid default value for 'registered_at'
在获取用户名的主要活动中，您可以制作另一种方法：
public void setLoggedin(boolean loggedin, String username){
editor.putBoolean("loggedInmode",loggedin);
editor.putString("username",username);
editor.commit();
}
您可以使用public boolean getUsername(){
return sharepref.getString("username", "");
}