Initial commit

app/src/main/AndroidManifest.xml

@@ -11,6 +11,9 @@
         android:supportsRtl="true"
         android:theme="@style/Theme.AppCompat.NoActionBar"
         tools:targetApi="31">
+        <activity
+            android:name=".activity.LoginActivity"
+            android:exported="false" />
         <activity
             android:name=".activity.RegisterActivity"
             android:exported="false" />

app/src/main/java/com/youxuegu/MainActivity.java

@@ -5,6 +5,7 @@ import androidx.appcompat.app.AppCompatActivity;
 import android.content.Intent;
 import android.os.Bundle;
 
+import com.youxuegu.activity.LoginActivity;
 import com.youxuegu.activity.RegisterActivity;
 
 /**
@@ -16,7 +17,7 @@ public class MainActivity extends AppCompatActivity {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
-        Intent intent = new Intent(MainActivity.this, RegisterActivity.class);
+        Intent intent = new Intent(MainActivity.this, LoginActivity.class);
         startActivity(intent);
     }
 }

app/src/main/java/com/youxuegu/activity/LoginActivity.java

@@ -0,0 +1,117 @@
+package com.youxuegu.activity;
+
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.view.View;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.TextView;
+import android.widget.Toast;
+
+import com.youxuegu.R;
+import com.youxuegu.utils.MD5Utils;
+import com.youxuegu.utils.UtilsHelper;
+
+public class LoginActivity extends AppCompatActivity implements View.OnClickListener {
+
+    private TextView tv_main_title;
+    private TextView tv_back, tv_register, tv_find_psw;
+    private Button btn_login;
+    private String userName, psw, spPsw;
+    private EditText et_user_name, et_psw;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_login);
+        init();
+    }
+
+    private void init() {
+        tv_main_title = findViewById(R.id.tv_main_title);
+        tv_main_title.setText("登录");
+        tv_back = findViewById(R.id.tv_back);
+        tv_register = findViewById(R.id.tv_register);
+        tv_find_psw = findViewById(R.id.tv_find_psw);
+        btn_login = findViewById(R.id.btn_login);
+        et_user_name = findViewById(R.id.et_user_name);
+        et_psw = findViewById(R.id.et_psw);
+        tv_back.setOnClickListener(this);
+        tv_register.setOnClickListener(this);
+        tv_find_psw.setOnClickListener(this);
+        btn_login.setOnClickListener(this);
+    }
+
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+        if (data != null) {
+            //从注册界面回传过来的用户名
+            String userName = data.getStringExtra("userName");
+            if (!TextUtils.isEmpty(userName)) {
+                et_user_name.setText(userName);
+                //设置光标位置
+                et_user_name.setSelection(userName.length());
+            }
+        }
+    }
+
+    @Override
+    public void onClick(View view) {
+        switch (view.getId()) {
+            //"返回"按钮的点击事件
+            case R.id.tv_back:
+                this.finish();
+                break;
+            //"立即注册"文本的点击事件
+            case R.id.tv_register:
+                Intent intent = new Intent(LoginActivity.this, RegisterActivity.class);
+                startActivityForResult(intent, 1);
+                break;
+            //"找回密码"文本的点击事件
+            case R.id.tv_find_psw:
+                //跳转到找回密码界面
+                //Intent findPswIntent = new Intent(LoginActivity.this, FindPswActivity.class);
+                //startActivity(findPswIntent);
+                break;
+            //"登录"按钮的点击事件
+            case R.id.btn_login:
+                userName = et_user_name.getText().toString().trim();
+                psw = et_psw.getText().toString().trim();
+                String md5Psw = MD5Utils.md5(psw);
+                //根据用户名读取系统中密码
+                spPsw = UtilsHelper.readPsw(LoginActivity.this, userName);
+                if (TextUtils.isEmpty(userName)) {
+                    //用户名为空
+                    Toast.makeText(LoginActivity.this, "请输入用户名", Toast.LENGTH_SHORT).show();
+                    return;
+                } else if (TextUtils.isEmpty(spPsw)) {
+                    //用户名未注册
+                    Toast.makeText(LoginActivity.this, "此用户名不存在", Toast.LENGTH_SHORT).show();
+                    return;
+                } else if (TextUtils.isEmpty(psw)) {
+                    //密码未输入
+                    Toast.makeText(LoginActivity.this, "请输入密码", Toast.LENGTH_SHORT).show();
+                    return;
+                } else if ((!TextUtils.isEmpty(spPsw) && !md5Psw.equals(spPsw))) {
+                    //密码输入错误
+                    Toast.makeText(LoginActivity.this, "输入的密码不正确", Toast.LENGTH_SHORT).show();
+                    return;
+                } else if (md5Psw.equals(spPsw)) {
+                    Toast.makeText(LoginActivity.this, "登录成功", Toast.LENGTH_SHORT).show();
+                    //保存登录状态和登录的用户名
+                    UtilsHelper.saveLoginStatus(LoginActivity.this, true, userName);
+                    //把登录成功的状态传递到MainActivity中
+                    Intent data = new Intent();
+                    data.putExtra("isLogin", true);
+                    setResult(RESULT_OK, data);
+                    LoginActivity.this.finish();
+                }
+                break;
+        }
+    }
+}

app/src/main/java/com/youxuegu/utils/UtilsHelper.java

@@ -21,6 +21,9 @@ public class UtilsHelper {
         return has_userName;
     }
 
+    /**
+     * 将密码用MD5加密
+     */
     public static void saveUserInfo(Context context, String userName, String psw) {
         //将密码用MD5加密
         String md5Psw = MD5Utils.md5(psw);
@@ -32,4 +35,28 @@ public class UtilsHelper {
         editor.putString(userName, md5Psw);
         editor.commit();//提交保存信息
     }
+
+    /**
+     * 根据用户名在文件loginInfo中返回密码信息
+     */
+    public static String readPsw(Context context, String userName) {
+        SharedPreferences sp = context.getSharedPreferences("loginInfo", Context.MODE_PRIVATE);
+        String spPsw = sp.getString(userName, "");
+        return spPsw;
+    }
+
+    /**
+     * 保存登录状态和登录用户名到SharedPreferences文件中
+     */
+    public static void saveLoginStatus(Context context, boolean status, String userName) {
+        SharedPreferences sp = context.getSharedPreferences("loginInfo", Context.MODE_PRIVATE);
+        //获取编辑器
+        SharedPreferences.Editor editor = sp.edit();
+        //存入boolean类型的登录状态
+        editor.putBoolean("isLogin", status);
+        //存入登录时的用户名
+        editor.putString("loginUserName", userName);
+        //提交修改
+        editor.commit();
+    }
 }

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

@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context=".activity.LoginActivity"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:background="@drawable/login_bg"
+    android:orientation="vertical">
+    <include layout="@layout/main_title_bar" />
+    <ImageView
+        android:id="@+id/iv_head"
+        android:layout_width="70dp"
+        android:layout_height="70dp"
+        android:layout_gravity="center_horizontal"
+        android:layout_marginTop="25dp"
+        android:background="@drawable/default_icon" />
+    <EditText
+        android:id="@+id/et_user_name"
+        style="@style/etRegisterStyle"
+        android:layout_gravity="center_horizontal"
+        android:layout_marginTop="35dp"
+        android:background="@drawable/login_user_name_bg"
+        android:drawableLeft="@drawable/user_name_icon"
+        android:hint="请输入用户名" />
+    <EditText
+        android:id="@+id/et_psw"
+        style="@style/etRegisterStyle"
+        android:background="@drawable/login_psw_bg"
+        android:drawableLeft="@drawable/psw_icon"
+        android:hint="请输入密码"
+        android:inputType="textPassword" />
+    <Button
+        android:id="@+id/btn_login"
+        style="@style/btnRegisterStyle"
+        android:text="登 录" />
+    <LinearLayout
+        android:layout_width="fill_parent"
+        android:layout_height="fill_parent"
+        android:layout_marginLeft="35dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginRight="35dp"
+        android:gravity="center_horizontal"
+        android:orientation="horizontal">
+        <TextView
+            android:id="@+id/tv_register"
+            style="@style/tvLoginStyle"
+            android:text="立即注册" />
+        <TextView
+            android:id="@+id/tv_find_psw"
+            style="@style/tvLoginStyle"
+            android:text="找回密码?" />
+    </LinearLayout>
+</LinearLayout>

app/src/main/res/values/themes.xml

@@ -39,4 +39,14 @@
         <item name="android:textColor">@android:color/white</item>
         <item name="android:textSize">18sp</item>
     </style>
+
+    <style name="tvLoginStyle">
+        <item name="android:layout_width">0dp</item>
+        <item name="android:layout_height">wrap_content</item>
+        <item name="android:layout_weight">1</item>
+        <item name="android:gravity">center_horizontal</item>
+        <item name="android:padding">8dp</item>
+        <item name="android:textColor">@android:color/white</item>
+        <item name="android:textSize">14sp</item>
+    </style>
 </resources>