用初学者的角度，用安卓写一个课表，可以添加课表、查看课表、修改课表，数据库用Sqlite，编程语言用java，带有注释

首先，在 Android Studio 中创建一个新项目，然后创建一个名为 "Course" 的 SQLite 数据库，其中包含一个名为 "courses" 的表，该表包含 "id"、"name"、"day"、"time" 和 "location" 列。接着编写以下代码：

创建一个名为 "Course" 的 Java 类，该类表示课程对象，其中包含以下属性：

public class Course {
    private int id;
    private String name;
    private String day;
    private String time;
    private String location;

    public Course(int id, String name, String day, String time, String location) {
        this.id = id;
        this.name = name;
        this.day = day;
        this.time = time;
        this.location = location;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getDay() {
        return day;
    }

    public String getTime() {
        return time;
    }

    public String getLocation() {
        return location;
    }
}

创建一个名为 "DatabaseHelper" 的 Java 类，该类扩展了 SQLiteOpenHelper 类，用于创建和管理数据库：

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "Course.db";
    private static final int DATABASE_VERSION = 1;

    private static final String COURSE_TABLE_NAME = "courses";
    private static final String COURSE_COLUMN_ID = "id";
    private static final String COURSE_COLUMN_NAME = "name";
    private static final String COURSE_COLUMN_DAY = "day";
    private static final String COURSE_COLUMN_TIME = "time";
    private static final String COURSE_COLUMN_LOCATION = "location";

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

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createCourseTable = "CREATE TABLE " + COURSE_TABLE_NAME + " (" +
                COURSE_COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COURSE_COLUMN_NAME + " TEXT, " +
                COURSE_COLUMN_DAY + " TEXT, " +
                COURSE_COLUMN_TIME + " TEXT, " +
                COURSE_COLUMN_LOCATION + " TEXT)";
        db.execSQL(createCourseTable);
    }

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

    public boolean insertCourse(String name, String day, String time, String location) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COURSE_COLUMN_NAME, name);
        contentValues.put(COURSE_COLUMN_DAY, day);
        contentValues.put(COURSE_COLUMN_TIME, time);
        contentValues.put(COURSE_COLUMN_LOCATION, location);
        long result = db.insert(COURSE_TABLE_NAME, null, contentValues);
        return result != -1;
    }

    public Cursor getAllCourses() {
        SQLiteDatabase db = getReadableDatabase();
        return db.rawQuery("SELECT * FROM " + COURSE_TABLE_NAME, null);
    }

    public boolean updateCourse(int id, String name, String day, String time, String location) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COURSE_COLUMN_NAME, name);
        contentValues.put(COURSE_COLUMN_DAY, day);
        contentValues.put(COURSE_COLUMN_TIME, time);
        contentValues.put(COURSE_COLUMN_LOCATION, location);
        int result = db.update(COURSE_TABLE_NAME, contentValues, COURSE_COLUMN_ID + " = ?", new String[]{Integer.toString(id)});
        return result != 0;
    }

    public boolean deleteCourse(int id) {
        SQLiteDatabase db = getWritableDatabase();
        int result = db.delete(COURSE_TABLE_NAME, COURSE_COLUMN_ID + " = ?", new String[]{Integer.toString(id)});
        return result != 0;
    }
}

在主活动（MainActivity）中，实例化数据库助手和适配器，然后使用 ListView 显示所有课程。添加、编辑和删除课程的操作可以通过对话框完成。

public class MainActivity extends AppCompatActivity {
    private DatabaseHelper databaseHelper;
    private CursorAdapter cursorAdapter;

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

        databaseHelper = new DatabaseHelper(this);

        ListView listView = findViewById(R.id.list_view);
        cursorAdapter = new SimpleCursorAdapter(
                this,
                android.R.layout.simple_list_item_2,
                databaseHelper.getAllCourses(),
                new String[]{DatabaseHelper.COURSE_COLUMN_NAME, DatabaseHelper.COURSE_COLUMN_DAY},
                new int[]{android.R.id.text1, android.R.id.text2},
                0
        );
        listView.setAdapter(cursorAdapter);

        listView.setOnItemClickListener((parent, view, position, id) -> {
            Cursor cursor = (Cursor) parent.getItemAtPosition(position);
            int courseId = cursor.getInt(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_ID));
            String name = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_NAME));
            String day = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_DAY));
            String time = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_TIME));
            String location = cursor.getString(cursor.getColumnIndex(DatabaseHelper.COURSE_COLUMN_LOCATION));
            showEditDialog(courseId, name, day, time, location);
        });

        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(view -> showAddDialog());
    }

    private void showAddDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Add Course");

        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_course, null);
        EditText nameEditText = view.findViewById(R.id.edit_text_name);
        Spinner daySpinner = view.findViewById(R.id.spinner_day);
        ArrayAdapter<String> dayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.days));
        dayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        daySpinner.setAdapter(dayAdapter);
        EditText timeEditText = view.findViewById(R.id.edit_text_time);
        EditText locationEditText = view.findViewById(R.id.edit_text_location);

        builder.setView(view);

        builder.setPositiveButton("Add", (dialog, which) -> {
            String name = nameEditText.getText().toString();
            String day = daySpinner.getSelectedItem().toString();
            String time = timeEditText.getText().toString();
            String location = locationEditText.getText().toString();

            boolean success = databaseHelper.insertCourse(name, day, time, location);
            if (success) {
                cursorAdapter.changeCursor(databaseHelper.getAllCourses());
            } else {
                Toast.makeText(this, "Failed to add course", Toast.LENGTH_SHORT).show();
            }
        });

        builder.setNegativeButton("Cancel", null);

        builder.show();
    }

    private void showEditDialog(int id, String name, String day, String time, String location) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Edit Course");

        View view = LayoutInflater.from(this).inflate(R.layout.dialog_edit_course, null);
        EditText nameEditText = view.findViewById(R.id.edit_text_name);
        nameEditText.setText(name);
        Spinner daySpinner = view.findViewById(R.id.spinner_day);
        ArrayAdapter<String> dayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, getResources().getStringArray(R.array.days));
        dayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        daySpinner.setAdapter(dayAdapter);
        daySpinner.setSelection(Arrays.asList(getResources().getStringArray(R.array.days)).indexOf(day));
        EditText timeEditText = view.findViewById(R.id.edit_text_time);
        timeEditText.setText(time);
        EditText locationEditText = view.findViewById(R.id.edit_text_location);
        locationEditText.setText(location);

        builder.setView(view);

        builder.setPositiveButton("Save", (dialog, which) -> {
            String newName = nameEditText.getText().toString();
            String newDay = daySpinner.getSelectedItem().toString();
            String newTime = timeEditText.getText().toString();
            String newLocation = locationEditText.getText().toString();

            boolean success = databaseHelper.updateCourse(id, newName, newDay, newTime, newLocation);
            if (success) {
                cursorAdapter.changeCursor(databaseHelper.getAllCourses());
            } else {
                Toast.makeText(this, "Failed to update course", Toast.LENGTH_SHORT).show();
            }
        });

        builder.setNegativeButton("Delete", (dialog, which) -> {
            boolean success = databaseHelper.deleteCourse(id);
            if (success) {
                cursorAdapter.changeCursor(databaseHelper.getAllCourses());
            } else {
                Toast.makeText(this, "Failed to delete course", Toast.LENGTH_SHORT).show();
            }
        });

        builder.setNeutralButton("Cancel", null);

        builder.show();
    }
}

在 res 文件夹中创建一个名为 "arrays.xml" 的文件，其中包含一组字符串数组，表示每周的某一天：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="days">
        <item>Sunday</item>
        <item>Monday</item>
        <item>Tuesday</item>
        <item>Wednesday</item>
        <item>Thursday</item>
        <item>Friday</item>
        <item>Saturday</item>
    </string-array>
</resources>

在 res 文件夹中创建一个名为 "dialog_edit_course.xml" 的布局文件，其中包含用于添加和编辑课程的文本框和下拉列表。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Name" />

    <EditText
        android:id="@+id/edit_text_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Day" />

    <Spinner
        android:id="@+id/spinner_day"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Time" />

    <EditText
        android:id="@+id/edit_text_time"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Location" />

    <EditText
        android:id="@+id/edit_text_location"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

现在可以运行应用程序，添加、编辑和删除课程了！