package com.example.Cat.activity; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; import com.example.Cat.R; import com.example.Cat.databaseoperation.User_Database; import com.example.Cat.entity.UserInfo; import java.util.List; public class MainActivity extends AppCompatActivity implements View.OnClickListener { private Button registerButton, loginButton; private EditText usernameText, paswdEdit; List list ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); User_Database user=new User_Database(MainActivity.this); SQLiteDatabase sqLiteDatabase=user.getReadableDatabase(); setContentView(R.layout.user_login); init(); } private void init() { usernameText = findViewById(R.id.username); paswdEdit = findViewById(R.id.password); loginButton = findViewById(R.id.login); loginButton.setOnClickListener(this); registerButton = findViewById(R.id.register); registerButton.setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.register: Intent intent = new Intent(MainActivity.this, RegisterActivity.class); startActivity(intent); break; case R.id.login: Verification(); break; } } //验证密码是否正确 public void Verification(){ //UserInfo info; Intent intent = new Intent(MainActivity.this, UserActivity.class); //intent.putExtra("username",usernameText.getText().toString()); User_Database user=new User_Database(MainActivity.this); SQLiteDatabase sqLiteDatabase=user.getReadableDatabase(); UserInfo info=user.queryByName(sqLiteDatabase,usernameText.getText().toString()); //info=list.get(0); if(info!=null){ intent.putExtra("username",usernameText.getText().toString()); if(paswdEdit.getText().toString().equals(info.getPaswd())){ startActivity(intent); } else{ Toast.makeText(this, "密码错误!", Toast.LENGTH_SHORT).show(); } } else{ Toast.makeText(this, "用户不存在!", Toast.LENGTH_SHORT).show(); } } }