使用room进行数据库操作

.idea/dbnavigator.xml

@@ -6,7 +6,7 @@
     <value-preview-pinned value="false" />
   </component>
   <component name="DBNavigator.Project.DatabaseBrowserManager">
-    <autoscroll-to-editor value="false" />
+    <autoscroll-to-editor value="true" />
     <autoscroll-from-editor value="true" />
     <show-object-properties value="true" />
     <loaded-nodes />
@@ -17,6 +17,21 @@
   <component name="DBNavigator.Project.DatabaseFileManager">
     <open-files />
   </component>
+  <component name="DBNavigator.Project.ExecutionManager">
+    <retain-sticky-names value="false" />
+  </component>
+  <component name="DBNavigator.Project.MethodExecutionManager">
+    <method-browser />
+    <execution-history>
+      <group-entries value="true" />
+      <execution-inputs />
+    </execution-history>
+    <argument-values-cache />
+  </component>
+  <component name="DBNavigator.Project.ObjectQuickFilterManager">
+    <last-used-operator value="EQUAL" />
+    <filters />
+  </component>
   <component name="DBNavigator.Project.Settings">
     <connections />
     <browser-settings>

app/src/main/java/cc/liuyx/app/LoginActivity.java

@@ -9,16 +9,27 @@ import android.widget.EditText;
 import android.widget.Toast;
 
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.room.Room;
+
+import cc.liuyx.app.dao.UserDao;
+import cc.liuyx.app.db.UserDB;
+import cc.liuyx.app.entity.User;
 
 public class LoginActivity extends AppCompatActivity implements View.OnClickListener {
 
     private EditText usernameEdit, passwdEdit;
+    private static UserDB db;
+    private UserDao userDao;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_login);
 
+        db = Room.databaseBuilder(getApplicationContext(), UserDB.class, "user")
+                .allowMainThreadQueries()
+                .build();
+
         usernameEdit = findViewById(R.id.login_username);
         passwdEdit = findViewById(R.id.login_passwd);
 
@@ -39,22 +50,36 @@ public class LoginActivity extends AppCompatActivity implements View.OnClickList
         }
     }
 
+    @Override
+    protected void onStop() {
+        super.onStop();
+        db.close();
+    }
+
     private void login() {
         String username = usernameEdit.getText().toString();
         String passwd = passwdEdit.getText().toString();
 
+        userDao = db.getUserDao();
+
         if (!username.equals("") && !passwd.equals("")) {
-            SharedPreferences sp = getSharedPreferences("loginStatus", MODE_PRIVATE);
-            String localName = sp.getString("username", null);
-            String localPasswd = sp.getString("passwd", null);
-            if (!username.equals(localName) || !passwd.equals(localPasswd)) {
-                Toast.makeText(LoginActivity.this, "用户名或密码错误>_<", Toast.LENGTH_SHORT).show();
+            // 在数据库中查询有无，如果有，则保存其登陆状态和信息
+            User user = userDao.findUserByName(username);
+            if (user == null) {
+                Toast.makeText(LoginActivity.this, "该用户还没有注册哦>_<", Toast.LENGTH_SHORT).show();
+                return;
+            }
+            if (!username.equals(user.getName()) || !passwd.equals(user.getPasswd())) {
+                Toast.makeText(LoginActivity.this, "您输入的密码有误", Toast.LENGTH_SHORT).show();
                 return;
             }
 
+            SharedPreferences sp = getSharedPreferences("loginStatus", MODE_PRIVATE);
             SharedPreferences.Editor editor = sp.edit();
             editor.putBoolean("isLoggedIn", true);
-            editor.putString("username", username);
+            editor.putString("username", user.getName());
+            editor.putString("email", user.getEmail());
+            editor.putString("phone", user.getPhone());
             editor.apply();
 
             Intent intent = new Intent(LoginActivity.this, MainActivity.class);
@@ -63,7 +88,5 @@ public class LoginActivity extends AppCompatActivity implements View.OnClickList
         } else {
             Toast.makeText(LoginActivity.this, "请填入用户名与密码哦~", Toast.LENGTH_SHORT).show();
         }
-
-
     }
 }

app/src/main/java/cc/liuyx/app/RegisterActivity.java

@@ -10,6 +10,11 @@ import android.widget.ImageView;
 import android.widget.Toast;
 
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.room.Room;
+
+import cc.liuyx.app.dao.UserDao;
+import cc.liuyx.app.db.UserDB;
+import cc.liuyx.app.entity.User;
 
 public class RegisterActivity extends AppCompatActivity implements View.OnClickListener {
 
@@ -20,12 +25,19 @@ public class RegisterActivity extends AppCompatActivity implements View.OnClickL
     private String email = "";
 
     private EditText usernameEdit, passwdEdit, passwdAgainEdit, phoneEdit, emailEdit;
+    private UserDao userDao;
+    private UserDB db;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_register);
 
+        db = Room.databaseBuilder(getApplicationContext(), UserDB.class, "user")
+                .allowMainThreadQueries()
+                .build();
+        userDao = db.getUserDao();
+
         // 初始化每个组件
         usernameEdit = findViewById(R.id.username);
         passwdEdit = findViewById(R.id.passwd);
@@ -45,6 +57,12 @@ public class RegisterActivity extends AppCompatActivity implements View.OnClickL
         });
     }
 
+    @Override
+    protected void onStop() {
+        super.onStop();
+        db.close();
+    }
+
     @Override
     public void onClick(View v) {
         if (v.getId() == R.id.btn_register) {
@@ -64,6 +82,14 @@ public class RegisterActivity extends AppCompatActivity implements View.OnClickL
         // 判断两次密码是否相等
         if (passwd.equals(passwdAgain)) {
             if (!username.equals("") && !passwd.equals("")) {
+                // 向数据库中插入新用户的数据
+                // 如果用户名重复，则此次操作不被允许
+                if (userDao.findUserByName(username) != null) {
+                    Toast.makeText(RegisterActivity.this, "已经存在该用户名啦", Toast.LENGTH_SHORT).show();
+                    return;
+                }
+                userDao.insert(new User(username, passwd, phone, email));
+
                 // 设置登录状态
                 SharedPreferences sharedPreferences = getSharedPreferences("loginStatus", Context.MODE_PRIVATE);
                 SharedPreferences.Editor editor = sharedPreferences.edit();
@@ -71,7 +97,6 @@ public class RegisterActivity extends AppCompatActivity implements View.OnClickL
                 editor.putString("username", username);
                 editor.putString("email", email);
                 editor.putString("phone", phone);
-                editor.putString("passwd", passwd);
                 editor.apply();
 
                 intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);

app/src/main/java/cc/liuyx/app/dao/UserDao.java

@@ -1,10 +1,30 @@
 package cc.liuyx.app.dao;
 
 import androidx.room.Dao;
+import androidx.room.Delete;
 import androidx.room.Insert;
+import androidx.room.Query;
+import androidx.room.Update;
+
+import java.util.List;
+
+import cc.liuyx.app.entity.User;
 
 @Dao
 public interface UserDao {
     @Insert
-    void insert();
+    void insert(User... users);
+
+    @Delete
+    void delete(User user);
+
+    @Update
+    void update(User user);
+
+    @Query("select * from user")
+    List<User> selectAllUser();
+
+    @Query("select * from user where name = :name")
+    User findUserByName(String name);
+
 }

app/src/main/java/cc/liuyx/app/db/UserDB.java

@@ -0,0 +1,12 @@
+package cc.liuyx.app.db;
+
+import androidx.room.Database;
+import androidx.room.RoomDatabase;
+
+import cc.liuyx.app.dao.UserDao;
+import cc.liuyx.app.entity.User;
+
+@Database(entities = User.class, version = 1, exportSchema = false)
+public abstract class UserDB extends RoomDatabase {
+    public abstract UserDao getUserDao();
+}

app/src/main/java/cc/liuyx/app/entity/User.java

@@ -18,6 +18,29 @@ public class User {
     @ColumnInfo(name = "email")
     private String email;
 
+    public User() {
+    }
+
+    public User(String name, String passwd, String phone, String email) {
+        this.name = name;
+        this.passwd = passwd;
+        this.phone = phone;
+        this.email = email;
+    }
+
+    public User(String name, String passwd) {
+        this.name = name;
+        this.passwd = passwd;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
     public String getName() {
         return name;
     }