2025.3.12

今天胃疼腹泻呕吐感觉要死了
但是补了一下作业
源程序代码：
package com.example.myapplication;

import android.annotation.SuppressLint;
import android.content.ContentValues;
import android.database.Cursor;
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 androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

private EditText courseNameEditText, teacherEditText, locationEditText;
private Button saveButton;
private MyDatabaseHelper dbHelper;

@SuppressLint("MissingInflatedId")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    courseNameEditText = findViewById(R.id.courseNameEditText);
    teacherEditText = findViewById(R.id.teacherEditText);
    locationEditText = findViewById(R.id.locationEditText);
    saveButton = findViewById(R.id.saveButton);
    dbHelper = new MyDatabaseHelper(this);

    saveButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String courseName = courseNameEditText.getText().toString();
            String teacher = teacherEditText.getText().toString();
            String location = locationEditText.getText().toString();

            if (isCourseNameUnique(courseName)) {
                if (isValidTeacher(teacher)) {
                    if (isValidLocation(location)) {
                        saveCourse(courseName, teacher, location);
                    } else {
                        Toast.makeText(MainActivity.this, "上课地点无效", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "无效的任课教师", Toast.LENGTH_SHORT).show();
                }
            } else {
                Toast.makeText(MainActivity.this, "课程名称重复，请重新输入", Toast.LENGTH_SHORT).show();
            }
        }
    });
}

private boolean isCourseNameUnique(String courseName) {
    SQLiteDatabase db = dbHelper.getReadableDatabase();
    Cursor cursor = db.query("courses", new String[]{"name"}, "name=?", new String[]{courseName}, null, null, null);
    boolean isUnique = !cursor.moveToFirst();
    cursor.close();
    return isUnique;
}

private boolean isValidTeacher(String teacher) {
    String[] validTeachers = {"王建民", "刘立嘉", "刘丹", "杨子光", "张云霞", "武永亮", "高飞", "孙静", "黄荣峰"};
    for (String validTeacher : validTeachers) {
        if (validTeacher.equals(teacher)) {
            return true;
        }
    }
    return false;
}

private boolean isValidLocation(String location) {
    return location.startsWith("一教") || location.startsWith("二教") || location.startsWith("三教") || location.startsWith("基教");
}

private void saveCourse(String courseName, String teacher, String location) {
    SQLiteDatabase db = dbHelper.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put("name", courseName);
    values.put("teacher", teacher);
    values.put("location", location);
    db.insert("courses", null, values);
    db.close();
    Toast.makeText(this, "课程添加成功", Toast.LENGTH_SHORT).show();
}

}

package com.example.myapplication;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class MyDatabaseHelper extends SQLiteOpenHelper {

private static final String DATABASE_NAME = "courses.db";
private static final int DATABASE_VERSION = 1;

public MyDatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
    String CREATE_COURSES_TABLE = "CREATE TABLE courses (" +
            "id INTEGER PRIMARY KEY AUTOINCREMENT," +
            "name TEXT," +
            "teacher TEXT," +
            "location TEXT" +
            ")";
    db.execSQL(CREATE_COURSES_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS courses");
    onCreate(db);
}

}

<EditText
    android:id="@+id/courseNameEditText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="请输入课程名称" />

<EditText
    android:id="@+id/teacherEditText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="请输入任课教师" />

<EditText
    android:id="@+id/locationEditText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="请输入上课地点" />

<Button
    android:id="@+id/saveButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="保存" />