sql

xml

<LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <EditText
            android:id="@+id/et_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="20sp"
            android:ems="20" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:id="@+id/btn_zj"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="onClick"
            android:text="增加记录"/>

        <Button
            android:id="@+id/btn_sc"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="onClick"
            android:text="删除第一条记录" />

    </LinearLayout>
    <ListView
        android:id="@+id/list_view"
        android:layout_width="match_parent"
        android:choiceMode="singleChoice"
        android:listSelector="#ffaa00"
        android:layout_weight="1"
        android:layout_height="0dp" />

 </LinearLayout>

student

public class Student implements Serializable {
private int _id;
private String name;
public Student(){
}
public Student(String name){
    this.name=name;
}

public int get_id() {
    return _id;
}

public void set_id(int _id) {
    this._id = _id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}
}

studentdao

public class StudentDAO {
private Context context;
private MyDBHelper helper;
private SQLiteDatabase db;

public StudentDAO(Context context) {
    helper = new MyDBHelper(context);
}

public void insert(Student student){
    db = helper.getWritableDatabase();

    // 第一种方法
    // 2. 生成数据集合
    ContentValues values = new ContentValues();
    values.put("name", student.getName());
    // 3. 执行语句
    db.insert("student", null, values);
}


public Cursor selectAll() {
    db = helper.getReadableDatabase();
    Cursor cursor = db.query("student",null,null,null,null,null,null);
    return cursor;
}
public void delete(int id){
    db = helper.getWritableDatabase();
    //根据数据的id号来删除数据
    db.delete("student","_id=?",new String[]{String.valueOf(id)});
}
}

mydhbhelper

public class MyDBHelper extends SQLiteOpenHelper {
//student表创建语句，字段包括：关键字id，姓名name，班级classmte，年龄age
private String sql="create table student(_id integer primary key autoincrement,"
        +"name text not null ,classmate text not null,age integer)";

public MyDBHelper(Context context) {
    super(context,"studentInfo",null,1);
}
//当app中没有数据库或数据库的版本为1的时候会被调用，且调用一次

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(sql);
}
//升级数据库表，当newVersion>oldVersion，会被调用
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table if exists stdent");
    onCreate(db);
}
}

MyCursorAdapter

public class MyCursorAdapter extends CursorAdapter {
public MyCursorAdapter(Context context, Cursor cursor) {
    super(context, cursor,0);
}

@Override
public View newView(Context context, Cursor cursor, ViewGroup viewGroup) {
    return LayoutInflater.from(context).inflate(R.layout.activity_main,viewGroup,false);
}
//给item的每个主键赋值
@Override
public void bindView(View view, Context context, Cursor cursor) {
    TextView name=(TextView)view.findViewById(R.id.et_name);

    name.setText(cursor.getString(cursor.getColumnIndex("name")));

}
}

MainActivity

 public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private ListView studentList;
    private Button btnzj;
    private Button btnsc;
private EditText etname;

    private MyCursorAdapter adapter;
    private StudentDAO studentDao;
    private Student student;
private Cursor cursor;

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

    studentList = (ListView) findViewById(R.id.list_view);
    etname=(EditText)findViewById(R.id.et_name);
    btnzj = (Button) findViewById(R.id.btn_zj);
    btnzj.setOnClickListener(this);
    btnsc = (Button) findViewById(R.id.btn_sc);
    btnsc.setOnClickListener(this);

    // 创建Adapter:CursorAdpater
    studentDao = new StudentDAO(this);
    if(cursor != null) {
        adapter = new MyCursorAdapter(this, cursor);
        studentList.setAdapter(adapter);
    }


    // ListView的item点击事件
        studentList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Cursor cursor = (Cursor) adapterView.getItemAtPosition(i);
                if(cursor != null) {
                    cursor.moveToPosition(i);
                    student = new Student();
                    student.setName(cursor.getString(cursor.getColumnIndex("name")));
                }
            }
        });
    }

        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.btn_zj:
                    String name = etname.getText().toString();
                    //对必填项做非空判断
                    if (TextUtils.isEmpty(name)) {
                        Toast.makeText(MainActivity.this, "姓名不能为空", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    //将这些数据存储到数据库
                    //组装name对象
                    Student student = new Student(name);
                    //调用nameDAO的insert()方法插入数据库
                    StudentDAO studentDAO = new StudentDAO(this);
                    studentDAO.insert(student);
                    Cursor cursor = studentDao.selectAll();
                    adapter.changeCursor(cursor);
                    Toast.makeText(this, "添加成功", Toast.LENGTH_SHORT).show();
                    break;
                case R.id.btn_sc:
                    if (student!= null) {
                        cursor.moveToFirst();
                        student = new Student();
                        student.set_id(cursor.getInt(cursor.getColumnIndex("_id")));
                        studentDao.delete(student.get_id());
                        studentDao = new StudentDAO(this);
                        cursor = studentDao.selectAll();
                        adapter = new MyCursorAdapter(this, cursor);
                        studentList.setAdapter(adapter);
                        Toast.makeText(MainActivity.this, "删除成功", Toast.LENGTH_SHORT).show();
                    }
                        Toast.makeText(MainActivity.this, "记录为空", Toast.LENGTH_SHORT).show();
                    break;
            }

            }
       }