安卓的简单的课程可以增删改查和数据库

安卓的课程可以分为以下几个部分：

1. UI设计：使用XML语言进行布局和设计，包括按钮、文本框、列表等控件的添加和使用。

2. 增删改查：使用Java语言编写相关代码，实现数据的增加、删除、修改和查询等功能。

3. 数据库：使用SQLite数据库进行数据的存储和管理，包括表的创建、数据的插入和查询等操作。

下面是一个简单的增删改查的例子：

1. 布局文件：

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="16dp">

    <EditText
        android:id="@+id/et_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="姓名"/>

    <EditText
        android:id="@+id/et_age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="年龄"/>

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

    <ListView
        android:id="@+id/list_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

2. Java代码：

public class MainActivity extends AppCompatActivity {
    private EditText etName, etAge;
    private Button btnSave;
    private ListView listView;
    private ArrayList<Person> persons;
    private PersonAdapter adapter;
    private DBHelper dbHelper;

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

        etName = findViewById(R.id.et_name);
        etAge = findViewById(R.id.et_age);
        btnSave = findViewById(R.id.btn_save);
        listView = findViewById(R.id.list_view);

        dbHelper = new DBHelper(this);

        persons = dbHelper.getAllPersons();
        adapter = new PersonAdapter(this, persons);
        listView.setAdapter(adapter);

        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = etName.getText().toString();
                int age = Integer.parseInt(etAge.getText().toString());

                Person person = new Person(name, age);
                dbHelper.addPerson(person);

                persons.add(person);
                adapter.notifyDataSetChanged();
            }
        });
    }

    class PersonAdapter extends ArrayAdapter<Person> {
        public PersonAdapter(Context context, ArrayList<Person> persons) {
            super(context, 0, persons);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            if (convertView == null) {
                convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item_person, parent, false);
            }

            TextView tvName = convertView.findViewById(R.id.tv_name);
            TextView tvAge = convertView.findViewById(R.id.tv_age);

            Person person = getItem(position);

            tvName.setText(person.getName());
            tvAge.setText(String.valueOf(person.getAge()));

            return convertView;
        }
    }
}

3. 数据库操作：

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

    private static final String TABLE_NAME = "persons";
    private static final String COLUMN_ID = "_id";
    private static final String COLUMN_NAME = "name";
    private static final String COLUMN_AGE = "age";

    private static final String SQL_CREATE_TABLE = "CREATE TABLE " + TABLE_NAME +
            " (" + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
            COLUMN_NAME + " TEXT," +
            COLUMN_AGE + " INTEGER)";

    private static final String SQL_DROP_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME;

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

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(SQL_CREATE_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL(SQL_DROP_TABLE);
        onCreate(db);
    }

    public void addPerson(Person person) {
        SQLiteDatabase db = getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(COLUMN_NAME, person.getName());
        values.put(COLUMN_AGE, person.getAge());

        db.insert(TABLE_NAME, null, values);

        db.close();
    }

    public ArrayList<Person> getAllPersons() {
        ArrayList<Person> persons = new ArrayList<>();

        SQLiteDatabase db = getReadableDatabase();

        String[] columns = {COLUMN_ID, COLUMN_NAME, COLUMN_AGE};

        Cursor cursor = db.query(TABLE_NAME, columns, null, null, null, null, null);

        while (cursor.moveToNext()) {
            int id = cursor.getInt(cursor.getColumnIndex(COLUMN_ID));
            String name = cursor.getString(cursor.getColumnIndex(COLUMN_NAME));
            int age = cursor.getInt(cursor.getColumnIndex(COLUMN_AGE));

            Person person = new Person(id, name, age);
            persons.add(person);
        }

        cursor.close();
        db.close();

        return persons;
    }
}

其中，Person类的定义如下：

public class Person {
    private int id;
    private String name;
    private int age;

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public Person(int id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

list_item_person.xml的定义如下：

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp"/>

    <TextView
        android:id="@+id/tv_age"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="16sp"/>
</LinearLayout>

以上代码实现了一个简单的增删改查功能，包括UI设计、Java代码和数据库操作。具体实现细节可以参考代码中的注释。