增加数据库类，使用了自带的数据库，可以在侧滑拦显示用户与角色

app/build.gradle

@@ -17,10 +17,10 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
+
 }
 
 dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     implementation 'com.google.android.material:material:1.0.0'

app/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="hunnu.sj.raise_money">
 
+    <uses-permission android:name="android.permission.INTERNET"/>
     <application
         android:allowBackup="true"
         android:icon="@drawable/img_2"
@@ -23,5 +24,4 @@
             android:label="@string/app_name"
             android:theme="@style/AppTheme.NoActionBar"></activity>
     </application>
-//丁望好帅
 </manifest>

app/src/main/java/hunnu/sj/raise_money/DataBase/DataBase.java

@@ -1,28 +0,0 @@
-package hunnu.sj.raise_money.DataBase;
-
-import java.sql.Connection;
-import java.sql.DriverManager;
-import java.sql.SQLException;
-
-public class DataBase {
-    private static String driver = "com.mysql.jdbc.Driver";// MySQL驱动
-    private static String url = "jdbc:mysql://localhost:3306/dogson";//MYSQL数据库连接Url
-    private static String user = "root";//用户名
-    private static String password = "";/* 密码 */
-
-    //连接数据库
-
-    public static Connection getConn(){
-        Connection conn = null;
-        try {
-            Class.forName(driver);//获取MYSQL驱动
-            conn = DriverManager.getConnection(url, user, password);//获取连接
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-        return conn;
-    }
-
-}

app/src/main/java/hunnu/sj/raise_money/DataBase/DatabaseHelper.java

@@ -0,0 +1,22 @@
+package hunnu.sj.raise_money.DataBase;
+import android.content.Context;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteDatabase.CursorFactory;
+import android.database.sqlite.SQLiteOpenHelper;
+
+public class DatabaseHelper extends SQLiteOpenHelper {
+    static String name="user.db";
+    static int dbVersion=1;
+    public DatabaseHelper(Context context) {
+        super(context, name, null, dbVersion);
+    }
+
+    public void onCreate(SQLiteDatabase db) {
+        String sql="create table user(id integer primary key autoincrement,username varchar(20),password varchar(20),role varchar(20))";
+        db.execSQL(sql);
+    }
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+
+    }
+
+}

app/src/main/java/hunnu/sj/raise_money/DataBase/UserService.java

@@ -0,0 +1,51 @@
+package hunnu.sj.raise_money.DataBase;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+
+import hunnu.sj.raise_money.User;
+
+public class UserService {
+    public DatabaseHelper dbHelper;
+    public UserService(Context context){
+        dbHelper=new DatabaseHelper(context);
+    }
+
+    public int login(String username,String password){
+        SQLiteDatabase sdb=dbHelper.getReadableDatabase();
+        String sql1 = "select * from user where username = ?";
+        String sql2 = "select * from user where username=? and password=?";
+        Cursor cursor1=sdb.rawQuery(sql1, new String[]{username});
+        Cursor cursor2=sdb.rawQuery(sql2, new String[]{username,password});
+        if(cursor1.moveToFirst()==false){
+            cursor1.close();
+            cursor2.close();
+            return 0;
+        }
+        if(cursor2.moveToFirst()==false){
+            cursor1.close();
+            cursor2.close();
+            return 1;
+        }
+        cursor1.close();
+        cursor2.close();
+        return 2;
+    }
+    public boolean register(User user){
+        SQLiteDatabase sdb=dbHelper.getReadableDatabase();
+        String sql="insert into user(username,password,role) values(?,?,?)";
+        Object obj[]={user.getName(),user.getPasd(),user.getRole()};
+        sdb.execSQL(sql, obj);
+        return true;
+    }
+
+    public String getRole(String username){
+        SQLiteDatabase sdb=dbHelper.getReadableDatabase();
+        String sql="select role from user where username = ?";
+        Cursor cursor=sdb.rawQuery(sql, new String[]{username});
+        cursor.moveToFirst();
+        String role = cursor.getString(cursor.getColumnIndex("role"));
+        return role;
+    }
+}

app/src/main/java/hunnu/sj/raise_money/RegiteActivity.java

@@ -2,12 +2,17 @@ package hunnu.sj.raise_money;
 
 import androidx.appcompat.app.AppCompatActivity;
 
+import android.content.Intent;
 import android.os.Bundle;
+import android.provider.MediaStore;
 import android.view.View;
+import android.widget.EditText;
+import android.widget.RadioButton;
+import android.widget.RadioGroup;
+import android.widget.Toast;
 
-import java.sql.Connection;
+import hunnu.sj.raise_money.DataBase.UserService;
 
-import hunnu.sj.raise_money.DataBase.DataBase;
 
 public class RegiteActivity extends AppCompatActivity {
 
@@ -17,8 +22,42 @@ public class RegiteActivity extends AppCompatActivity {
         setContentView(R.layout.activity_registe);
     }
 
-    protected void onRegiste(View view){
+    public void onRegister(View view){
-        Connection conn = DataBase.getConn();
+        EditText user_name = findViewById(R.id.user_name);
+        EditText pass_word = findViewById(R.id.pass_word);
+        EditText repass_word = findViewById(R.id.repass_word);
+        String role = "默认角色";
+        RadioButton radio1 = findViewById(R.id.ratio1);
+        RadioButton radio2 = findViewById(R.id.radio2);
+        if(radio1.isChecked()){
+            role = "爱心人士";
+        }else if(radio2.isChecked()){
+            role = "贫困学生";
+        }
+        String username = user_name.getText().toString();
+        String password = pass_word.getText().toString();
+        String repassword = repass_word.getText().toString();
+        UserService uService = new UserService(RegiteActivity.this);
+        if(username.trim().equals("")){
+            user_name.setError("请输入昵称");
+        }else if(password.trim().equals("")){
+            pass_word.setError("请输入密码");
+        }
+        if(!password.equals(repassword)){
+            repass_word.setText("");
+            repass_word.setError("密码验证错误");
+        }else if(uService.login(username,password)==1){
+            user_name.setError("用户已存在");
+        }else{
+            User user = new User();
+            user.setName(username);
+            user.setPasd(password);
+            user.setRole(role);
+            uService.register(user);
+            Intent intent = new Intent(this,SignInActivity.class);
+            startActivity(intent);
+        }
+
 
     }
 }

app/src/main/java/hunnu/sj/raise_money/SignInActivity.java

@@ -14,7 +14,7 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
-import hunnu.sj.raise_money.DataBase.DataBase;
+import hunnu.sj.raise_money.DataBase.UserService;
 
 public class SignInActivity extends AppCompatActivity {
     public static final String IS_SIGNIN = "is.user.sign.in";
@@ -29,47 +29,30 @@ public class SignInActivity extends AppCompatActivity {
         EditText pswd = findViewById(R.id.pass_word);
         String name = usnm.getText().toString();
         String pasd = pswd.getText().toString();
-        String sql = "select * from User";
-        Connection conn = DataBase.getConn();
-        try {
-            if(conn!=null){
-               PreparedStatement ps = conn.prepareStatement(sql);
-               if(ps!=null){
-                   ResultSet rs = ps.executeQuery();
-                   if(rs!=null&&rs.next()){
-                       User user = new User();
-                       user.setName(rs.getString("username"));
-                       user.setPasd(rs.getString("password"));
-                       user.setRole(rs.getString("role"));
-                       conn.commit();
-                       conn.close();
-                       Bundle bundle = new Bundle();
-                       bundle.putSerializable("user",user);
-                       Intent intent =new Intent(this,MainActivity.class);
-                       intent.putExtras(bundle);
-                       startActivity(intent);
-                   }
-               }
-            }
-        }catch (SQLException e){
-            e.printStackTrace();
-        }
 
 
-        /*if(!name.equals("admin")){
+        UserService uService = new UserService(SignInActivity.this);
+        if(uService.login(name,pasd)==0){
             usnm.setError("用户名错误");
-        }else if(!pasd.equals("admin")){
+        }else if(uService.login(name,pasd)==1){
             pswd.setError("密码错误");
         }else{
             User user = new User();
             user.setName(name);
             user.setPasd(pasd);
+            String role = uService.getRole(name);
+            user.setRole(role);
+            //String role = uService.getRole(name);
+            //user.setRole(role);
             Bundle bundle = new Bundle();
-           /* bundle.putSerializable("user",user);
+            bundle.putSerializable("user",user);
             Intent intent =new Intent(this,MainActivity.class);
             intent.putExtras(bundle);
-            startActivity(intent);*/
+            startActivity(intent);
         }
+
+    }
+
     public void onToRegister(View view){
         Intent intent = new Intent(this,RegiteActivity.class);
         startActivity(intent);

app/src/main/java/hunnu/sj/raise_money/User.java

@@ -6,6 +6,16 @@ public class User implements Serializable{
     private String name;
     private String pasd;
     private String role;
+    public User(){
+        super();
+    }
+    public User(String name,String pasd,String role){
+        super();
+        this.name = name;
+        this.pasd = pasd;
+        this.role = role;
+    }
+
     public void setName(String name) {
         this.name = name;
     }

app/src/main/res/layout/activity_registe.xml

@@ -49,9 +49,10 @@
         app:layout_constraintVertical_bias="0.362" />
 
     <Button
-        android:id="@+id/registe"
+        android:id="@+id/register"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
+        android:onClick="onRegister"
         android:text="注册"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
@@ -61,6 +62,7 @@
         app:layout_constraintVertical_bias="0.765" />
 
     <RadioGroup
+        android:id="@+id/ratio"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         app:layout_constraintBottom_toBottomOf="parent"
@@ -74,6 +76,7 @@
             android:id="@+id/ratio1"
             android:layout_width="168dp"
             android:layout_height="wrap_content"
+            android:checked="true"
             android:text="爱心人士" />
 
         <RadioButton