【Android 记事本，笔记本，可注册登录，增删改查（附源码）】

简介

用Sqlite做数据库，用来存储账号以及笔记信息，实现了账号的注册以及登录功能，笔记方面实现了新增、删除、修改、搜索功能，列表展示笔记使用的是listView（懒得弄分割线，就使用listView的默认分割线了）；

运行效果

代码讲解

我代码里使用了两个依赖，一个是工具类，一个是标题栏，工具类是使用里面的SPUtils保存当前登录的账号信息，不用再次输入账号密码，可按需引入

	//标题栏
    implementation 'com.github.FlyJingFish:TitleBar:1.2.5'
    //工具类
    implementation 'com.blankj:utilcodex:1.31.1'

首先是数据库的实现部分，新建一个DBOpenHelper 类，继承SQLiteOpenHelper

public class DBOpenHelper extends SQLiteOpenHelper {
    
    
     private DBOpenHelper dbOpenHelper;
     private SQLiteDatabase db;
     private static final String DBNAME="notes.db";
     private static final int VERSION=1;
     public DBOpenHelper(Context context) {
    
    
         super(context, DBNAME, null, VERSION);
        dbOpenHelper=this;
        db=dbOpenHelper.getWritableDatabase();
     }
    //创建数据库
     @Override
     public void onCreate(SQLiteDatabase db) {
    
    
    //创建数据表
     db.execSQL("create table if not exists user(id INTEGER primary key autoincrement,username varchar(25),password varchar(20))");
     db.execSQL("create table if not exists notes(id INTEGER primary key autoincrement,title varchar(20),content varchar(255),time varchar(20)," +
             "username varchar(20))");
     }
    //升级数据库
     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
    {
    
    
 
     }

    //插入用户数据
    public boolean insertUserData(String username,String password){
    
    
        ContentValues contentValues=new ContentValues();
        contentValues.put("username",username);
        contentValues.put("password",password);
        return db.insert("user",null,contentValues)>0;
    }

    public boolean insertNotes(String title,String content,String time,String username){
    
    
        ContentValues contentValues=new ContentValues();
        contentValues.put("title",title);
        contentValues.put("content",content);
        contentValues.put("time",time);
        contentValues.put("username",username);
        return db.insert("notes",null,contentValues)>0;
    }

    public boolean updateNotes(String id,String title,String content,String time){
    
    
        ContentValues contentValues=new ContentValues();
        contentValues.put("title",title);
        contentValues.put("content",content);
        contentValues.put("time",time);
        String sql="id=?";
        String[] strings=new String[]{
    
    id};
        return db.update("notes",contentValues,sql,strings)>0;
    }

    public boolean deleteNotes(String id){
    
    
        String sql="id=?";
        String[] contentValuesArray=new String[]{
    
    id};
        return db.delete("notes",sql,contentValuesArray)>0;
    }

    //获取笔记
    public List<Notes> getNotes(String query){
    
    
        List<Notes> list=new ArrayList<>();
        Cursor cursor;
        if (query==null){
    
    
            cursor=db.rawQuery("select * from notes where username =?",new String[]{
    
    SPUtils.getInstance().getString("username")});
        }
        else {
    
    
            cursor=db.rawQuery("select * from notes where username =? and title like ?",new String[]{
    
    SPUtils.getInstance().getString("username"),"%"+query+"%"});
        }
        if (cursor!=null){
    
    
            while (cursor.moveToNext()){
    
    
                @SuppressLint("Range") int id=cursor.getInt(cursor.getColumnIndex("id"));
                @SuppressLint("Range") String title=cursor.getString(cursor.getColumnIndex("title"));
                @SuppressLint("Range") String content=cursor.getString(cursor.getColumnIndex("content"));
                @SuppressLint("Range") String time=cursor.getString(cursor.getColumnIndex("time"));
                @SuppressLint("Range") String user=cursor.getString(cursor.getColumnIndex("username"));
                Notes note=new Notes(id,title,content,time,user);
                list.add(note);
            }
            cursor.close();
        }
        return list;
    }
}

然后是基类Activity，这个是为了方便统一管理标题栏和数据库

创建一个BaseActivity，继承AppCompatActivity

public class BaseActivity extends AppCompatActivity {
    
    
    protected TitleBar titleBar;
    protected DBOpenHelper dbOpenHelper;
    protected SQLiteDatabase db;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        initTitle();
        dbOpenHelper=new DBOpenHelper(this);
        db=dbOpenHelper.getWritableDatabase();
    }
    public void initTitle(){
    
    
        titleBar = new TitleBar(this);
        titleBar.setShadow(1, Color.parseColor("#40454545"), TitleBar.ShadowType.GRADIENT);
        titleBar.setTitleGravity(TitleBar.TitleGravity.CENTER);
        titleBar.setOnBackViewClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                finish();
            }
        });
        titleBar.setAboveContent(true);
        titleBar.attachToWindow();
    }

    @Override
    protected void onDestroy() {
    
    
        super.onDestroy();
        db.close();
        dbOpenHelper.close();
    }
}

然后就是笔记实体类

public class Notes implements Serializable {
    
    
    private int id;
    private String title;
    private String content;
    private String time;
    private String username;

    public int getId() {
    
    
        return id;
    }

    public void setId(int id) {
    
    
        this.id = id;
    }

    public String getTitle() {
    
    
        return title;
    }

    public void setTitle(String title) {
    
    
        this.title = title;
    }

    public String getContent() {
    
    
        return content;
    }

    public void setContent(String content) {
    
    
        this.content = content;
    }

    public String getTime() {
    
    
        return time;
    }

    public void setTime(String time) {
    
    
        this.time = time;
    }

    public String getUsername() {
    
    
        return username;
    }

    public void setUsername(String username) {
    
    
        this.username = username;
    }

    public Notes() {
    
    
    }

    public Notes(int id, String title, String content, String time,String user) {
    
    
        this.id = id;
        this.title = title;
        this.content = content;
        this.time = time;
    }

    @Override
    public String toString() {
    
    
        return "Notes{" +
                "id=" + id +
                ", title='" + title + '\'' +
                ", content='" + content + '\'' +
                ", time='" + time + '\'' +
                ", username='" + username + '\'' +
                '}';
    }
}

登录注册页面

登录页面

public class Login extends BaseActivity {
    
    
    private EditText username,password;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        titleBar.setTitle("登录");
        titleBar.setDisplayLeftView(false);

        username=findViewById(R.id.et_user_name);
        password=findViewById(R.id.et_psw);

        String name=SPUtils.getInstance().getString("username");
        String pw=SPUtils.getInstance().getString("password");
        if (!TextUtils.isEmpty(name)&&!TextUtils.isEmpty(pw)){
    
    
            username.setText(name);
            password.setText(pw);
        }
        //点击登录
        findViewById(R.id.btn_login).setOnClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                login();
            }
        });

        //去注册
        findViewById(R.id.btn_register).setOnClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                Intent intent=new Intent(Login.this, Register.class);
                intent.putExtra("flag","login");
                startActivity(intent);
            }
        });
    }
    public void login(){
    
    
        String name =username.getText().toString();
        String pw   =password.getText().toString();

        if (name.equals("")||pw.equals("")){
    
    
            Toast.makeText(Login.this,"请输入账号密码！",Toast.LENGTH_SHORT).show();
        }
        else {
    
    
            //查询用户
            @SuppressLint("Recycle") Cursor cursor=db.rawQuery("select * from user where username=?",new String[]{
    
    name});
            cursor.moveToFirst();
            if (cursor.getCount()==0){
    
    
                Toast.makeText(Login.this,"不存在该用户！",Toast.LENGTH_SHORT).show();
            }
            else{
    
    
                @SuppressLint("Range") String password=cursor.getString(cursor.getColumnIndex("password"));
                if (pw.equals(password)){
    
    
                    Toast.makeText(Login.this,"登录成功！",Toast.LENGTH_SHORT).show();
                    Intent intent=new Intent(Login.this, MainActivity.class);
                    startActivity(intent);
                    finish();
                    //保存用户名到SharedPreferences
                    SPUtils.getInstance().put("username",name);
                    SPUtils.getInstance().put("password",pw);
                }else {
    
    
                    Toast.makeText(Login.this,"密码错误！",Toast.LENGTH_SHORT).show();
                }
            }
        }
    }
}

登录页面xml文件

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".ui.Login">

    <EditText
        android:id="@+id/et_user_name"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="@drawable/edittext_style"
        android:gravity="center_vertical"
        android:hint="请输入用户名"
        android:paddingLeft="15dp"
        android:layout_marginHorizontal="20dp"
        android:singleLine="true"
        android:textColor="@color/black"
        android:textSize="14sp" />
    <!--输入框-->
    <EditText
        android:id="@+id/et_psw"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="@drawable/edittext_style"
        android:gravity="center_vertical"
        android:hint="请输入密码"
        android:paddingLeft="15dp"
        android:layout_marginHorizontal="20dp"
        android:layout_marginTop="10dp"
        android:inputType="textPassword"
        android:singleLine="true"
        android:textColor="@color/black"
        android:textSize="14sp" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:layout_marginTop="20dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btn_login"
            android:layout_width="150dp"
            android:layout_height="50dp"
            android:layout_gravity="center_horizontal"
            android:layout_marginLeft="35dp"
            android:layout_marginRight="35dp"
            android:background="@drawable/button_style"
            android:text="登 录"
            android:textColor="@android:color/white"
            android:textSize="18sp" />
        <Button
            android:id="@+id/btn_register"
            android:layout_width="150dp"
            android:layout_height="50dp"
            android:layout_gravity="center_horizontal"
            android:layout_marginLeft="15dp"
            android:layout_marginRight="35dp"
            android:background="@drawable/button_style"
            android:text="注册"
            android:textColor="@android:color/white"
            android:textSize="18sp" />
    </LinearLayout>
</LinearLayout>

注册页面

public class Register extends BaseActivity {
    
    
    private EditText username,password,pw_again;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        titleBar.setTitle("欢迎注册");

        username=findViewById(R.id.et_user_name);
        password=findViewById(R.id.et_psw);
        pw_again=findViewById(R.id.et_psw_again);

        //注册
        findViewById(R.id.btn_register).setOnClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                register();
            }
        });
    }

    public void register(){
    
    
        String name =username.getText().toString();
        String pw   =password.getText().toString();
        String pwa =pw_again.getText().toString();

        if (name.equals("")||pw.equals("")||pwa.equals("")){
    
    
            Toast.makeText(Register.this,"请输入完整！",Toast.LENGTH_SHORT).show();
        }
        else {
    
    
            //查询用户
            Cursor cursor = db.rawQuery("select * from user where username=?", new String[]{
    
    name});
            cursor.moveToFirst();
            if (cursor.getCount() == 0) {
    
    
                if (!pw.equals(pwa)) {
    
    
                    Toast.makeText(Register.this, "两次密码不相同！", Toast.LENGTH_SHORT).show();
                } else {
    
    
                    if (dbOpenHelper.insertUserData(name, pw)){
    
    
                        Toast.makeText(Register.this, "注册成功！", Toast.LENGTH_SHORT).show();
                        finish();
                    }
                }
            } else {
    
    
                Toast.makeText(Register.this, "该用户已存在！", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

首页

首页

public class MainActivity extends BaseActivity {
    
    
    private List<Notes> noteList=new ArrayList<>();
    private ListView listView;
    private NoteAdapter noteAdapter;
    private SearchView searchView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        titleBar.setTitle("我的记事本");
        titleBar.getRightTextView().setText("新增");
        titleBar.setOnRightViewClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                startActivity(new Intent(MainActivity.this, AddNote.class));
            }
        });
        listView=findViewById(R.id.listView);
        searchView=findViewById(R.id.searchView);

        //初始化适配器
        noteAdapter=new NoteAdapter(this,R.layout.note_item, noteList);
        //设置适配器
        listView.setAdapter(noteAdapter);


        //搜索笔记
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
    
    
            @Override
            public boolean onQueryTextSubmit(String query) {
    
    
                if (!TextUtils.isEmpty(query)){
    
    
                    noteList.clear();
                    noteList.addAll(dbOpenHelper.getNotes(query));
                    noteAdapter.notifyDataSetChanged();
                    searchView.clearFocus();
                }
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
    
    
                if (TextUtils.isEmpty(newText)){
    
    
                    noteList.clear();
                    noteList.addAll(dbOpenHelper.getNotes(null));
                    noteAdapter.notifyDataSetChanged();
                    searchView.clearFocus();
                }
                return false;
            }
        });
    }

    @Override
    protected void onResume() {
    
    
        super.onResume();
        noteList.clear();
        noteList.addAll(dbOpenHelper.getNotes(null));
        noteAdapter.notifyDataSetChanged();
    }
}

首页xml文件

<?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"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.MainActivity">

    <androidx.appcompat.widget.SearchView
        android:id="@+id/searchView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        app:iconifiedByDefault="false"
        android:background="@drawable/edittext_style"
        app:queryHint="输入内容进行搜索"
        android:layout_marginHorizontal="20dp"/>

    <ListView
        android:id="@+id/listView"
        android:layout_marginTop="5dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</LinearLayout>

最后一个就是新增笔记页面了

由于新增和修改差不多，所以都放在一个页面了，根据flag来判断是新增还是修改

public class AddNote extends BaseActivity {
    
    
    private EditText title,content;
    private TextView number,time;
    private String flag;
    private Notes note;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add_note);
        title=findViewById(R.id.title);
        content=findViewById(R.id.content);
        number=findViewById(R.id.number);
        time=findViewById(R.id.time);
        flag = getIntent().getStringExtra("flag");
        titleBar.getRightTextView().setText("保存");
        if (flag!=null){
    
    
            note = (Notes) getIntent().getSerializableExtra("entity");
            title.setText(note.getTitle());
            content.setText(note.getContent());
            time.setText("上次修改时间:"+ note.getTime());
            number.setText(note.getContent().length()+"字");
            titleBar.setTitle("修改记事本");
        }
        //设置时间
        else {
    
    
            Date date = new Date(System.currentTimeMillis());
            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss", Locale.CHINA);
            time.setText(simpleDateFormat.format(date));
            titleBar.setTitle("新增记事本");
        }

        //更新字数
        content.addTextChangedListener(new TextWatcher() {
    
    
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
    
    
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
    
    
                number.setText(content.getText().toString().length()+"字");
            }

            @Override
            public void afterTextChanged(Editable editable) {
    
    
            }
        });

        titleBar.setOnRightViewClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                Date date = new Date(System.currentTimeMillis());
                SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss", Locale.CHINA);
                if (!"".equals(title.getText().toString())&&!"".equals(content.getText().toString())){
    
    
                    if (flag==null){
    
    
                        if (dbOpenHelper.insertNotes(title.getText().toString(),content.getText().toString(),simpleDateFormat.format(date), SPUtils.getInstance().getString("username"))){
    
    
                            Toast.makeText(AddNote.this, "保存成功！", Toast.LENGTH_SHORT).show();
                        }
                        else {
    
    
                            Toast.makeText(AddNote.this, "未知错误", Toast.LENGTH_SHORT).show();
                        }
                    }
                    else {
    
    
                        if (dbOpenHelper.updateNotes(String.valueOf(note.getId()),title.getText().toString(),content.getText().toString(),simpleDateFormat.format(date))){
    
    
                            Toast.makeText(AddNote.this, "修改成功！", Toast.LENGTH_SHORT).show();
                        }
                        else {
    
    
                            Toast.makeText(AddNote.this, "未知错误", Toast.LENGTH_SHORT).show();
                        }
                    }
                    finish();
                }
                else {
    
    
                    Toast.makeText(AddNote.this, "请输入内容！", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

xml文件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.AddNote">
    <TextView
        android:id="@+id/time"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="16sp"
        android:layout_marginTop="20dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.065"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/number"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="0字"
        android:textSize="16sp"
        android:layout_marginTop="20dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.077"
        app:layout_constraintStart_toEndOf="@+id/time"
        app:layout_constraintTop_toTopOf="parent"  />

    <EditText
        android:id="@+id/title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="标题"
        android:inputType="text"
        android:lines="1"
        android:maxLength="10"
        android:paddingLeft="10dp"
        android:textColor="@color/black"
        android:textSize="30sp"
        android:layout_marginTop="10dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/number"
        android:autofillHints="" />
    <EditText
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:hint="内容"
        android:background="@null"
        android:gravity="start"
        android:textSize="25sp"
        android:paddingStart="10dp"
        android:textColor="@color/black"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/title"
        android:autofillHints="" />
</androidx.constraintlayout.widget.ConstraintLayout>

最后就是listView的适配器了

//listview适配器
public class NoteAdapter extends ArrayAdapter<Notes> {
    
    
    private Context context;
    private DBOpenHelper dbOpenHelper;

    //构造方法
    public NoteAdapter(@NonNull Context context, int resource, List<Notes> diaryList) {
    
    
        super(context, resource,diaryList);
        this.context=context;
        dbOpenHelper=new DBOpenHelper(context);
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    
    
        Notes note=getItem(position);
        @SuppressLint("ViewHolder") View view= LayoutInflater.from(getContext()).inflate(R.layout.note_item,parent,false);
        TextView title = view.findViewById(R.id.title);
        TextView create_time = view.findViewById(R.id.create_time);
        TextView content=view.findViewById(R.id.content);
        ImageView del = view.findViewById(R.id.del);
        LinearLayout constraintLayout=view.findViewById(R.id.con);

        //设置item内容
        title.setText(note.getTitle());
        content.setText(note.getContent());
        create_time.setText(note.getTime());
        //删除item
        del.setOnClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                if (dbOpenHelper.deleteNotes(String.valueOf(note.getId()))){
    
    
                    Toast.makeText(context,"已删除",Toast.LENGTH_SHORT).show();
                    remove(note);
                    notifyDataSetChanged();
                }
                else {
    
    
                    Toast.makeText(context, "删除失败", Toast.LENGTH_SHORT).show();
                }
            }
        });
        //单击item
        constraintLayout.setOnClickListener(new View.OnClickListener() {
    
    
            @Override
            public void onClick(View view) {
    
    
                Intent intent=new Intent(context, AddNote.class);
                //设置flag
                intent.putExtra("flag","update");
                //将笔记内容传递过去
                intent.putExtra("entity",note);
                context.startActivity(intent);
            }
        });
        return view;
    }
}

全部代码基本就是这些了，有什么问题欢迎评论区留言

源码

github：https://github.com/panzhusheng/Notes
gitee：https://gitee.com/pan-zs/notes