使用GreenDao3.0实现一个记事本App

1.项目的创建

打开Android studio新建一个MyNotePad项目.

2.导入依赖以及相关配置

app 的build.gradle文件头部添加

apply plugin: 'android-apt'apply plugin: 'org.greenrobot.greendao'

下面是添加的依赖项目

compile 'com.android.support:cardview-v7:25.3.1'compile 'com.jakewharton:butterknife:8.6.0'apt 'com.jakewharton:butterknife-compiler:8.6.0'compile 'com.android.support:recyclerview-v7:25.3.1'compile'org.greenrobot:greendao:3.2.2'compile'org.greenrobot:greendao-generator:3.2.2'

工程的builde.gradle文件

buildscript {    repositories {        jcenter()    }    dependencies {        classpath 'com.android.tools.build:gradle:2.3.3'        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'        classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'        // NOTE: Do not place your application dependencies here; they belong        // in the individual module build.gradle files    }}

app 的build.gradle文件android目录添加

greendao {    schemaVersion 1    daoPackage 'nanjing.jun.mynotepad.entity'    targetGenDir 'src/main/java'}

3.创建一个日记的实体类

我们这里只要把这个实体类的属性和get,setter写好就行了

@Entitypublic class Note {    private Long id;    private String content;    private String date;    public Note(Long id, String content, String date) {        this.id = id;        this.content = content;        this.date = date;    }    public Note() {    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getContent() {        return this.content;    }    public void setContent(String content) {        this.content = content;    }    public String getDate() {        return this.date;    }    public void setDate(String date) {        this.date = date;    }}

实体类写好了之后我们build一次工程,我们会发现我们的实体类被改造了

@Entitypublic class Note {    @Id    private Long id;    @Property(nameInDb = "NOTECONTENT")    private String content;    @Property(nameInDb = "NOTEDATE")    private String date;    @Generated(hash = 1881903072)    public Note(Long id, String content, String date) {        this.id = id;        this.content = content;        this.date = date;    }    @Generated(hash = 1272611929)    public Note() {    }    public Long getId() {        return this.id;    }    public void setId(Long id) {        this.id = id;    }    public String getContent() {        return this.content;    }    public void setContent(String content) {        this.content = content;    }    public String getDate() {        return this.date;    }    public void setDate(String date) {        this.date = date;    }}

我们这个应用就创建这一个实体类就行了.在我们创建好了这个实体类后,我们build一次工程,让greendao-generator帮我们自动生成相应的代码.
如下截图,是build之后生成的类

我们看到自动帮我们生成了DaoMaster,DaoSession,NoteDao文件

4.接下来我们重写一个Application

public class NoteApp extends Application {    private static NoteApp noteApp;    private DaoMaster.DevOpenHelper helper;    private SQLiteDatabase database;    private DaoMaster daoMaster;    private DaoSession daoSession;    public static NoteApp getInstnca() {        return noteApp;    }    @Override    public void onCreate() {        super.onCreate();        noteApp = this;        setDatabase();    }    private void setDatabase() {        helper = new DaoMaster.DevOpenHelper(this, "notedb", null);        database = helper.getWritableDatabase();        daoMaster = new DaoMaster(database);        daoSession = daoMaster.newSession();    }    public DaoSession getDaoSession() {        return daoSession;    }    public SQLiteDatabase getDatabase() {        return database;    }}

我们主要看下setDataBase方法就行了,我们在这里主要拿到这个session就行了,就让这个session来干活,最后别忘了在manifest文件里面注册一下.

5.完成新增日记的界面

看下新增日记界面的布局文件activity_create_note.xml

<?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:background="#f0f0f0"    android:orientation="vertical"    tools:context="nanjing.jun.mynotepad.MainActivity">    <android.support.design.widget.AppBarLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:theme="@style/AppTheme.AppBarOverlay">        <android.support.v7.widget.Toolbar            android:id="@+id/toolbar"            android:layout_width="match_parent"            android:layout_height="?attr/actionBarSize"            android:background="?attr/colorPrimary"            app:popupTheme="@style/AppTheme.PopupOverlay" />    </android.support.design.widget.AppBarLayout>    <EditText        android:id="@+id/note_content"        android:layout_width="match_parent"        android:layout_height="200dp"        android:layout_margin="10dp"        android:background="#fff"        android:gravity="start"        android:hint="记录每天点点滴滴"        android:padding="5dp" />    <Button        android:id="@+id/save"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="保存" /></LinearLayout>

就一个EditText和一个Button,接下就是实现对应的activity了

public class CreateNoteActivity extends AppCompatActivity {    @BindView(R.id.toolbar)    Toolbar toolbar;    @BindView(R.id.note_content)    EditText noteContent;    @BindView(R.id.save)    Button save;    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_create_note);        ButterKnife.bind(this);        setSupportActionBar(toolbar);        getSupportActionBar().setDisplayHomeAsUpEnabled(true);    }    @OnClick(R.id.save)    public void onClick() {        if (noteContent.getText().toString().length() == 0) {            Toast.makeText(this, "未输入任何内容", Toast.LENGTH_SHORT).show();            return;        }        Note note = new Note();        note.setContent(noteContent.getText().toString());        note.setDate(simpleDateFormat.format(new Date()));        NoteApp.getInstnca().getDaoSession().getNoteDao().insert(note);        finish();    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        switch (item.getItemId()) {            case android.R.id.home:                finish();                break;        }        return super.onOptionsItemSelected(item);    }}

CreateNoteActivity最关键的一句代码就是NoteApp.getInstnca().getDaoSession().getNoteDao().insert(note);插入一条记录.我们可以重写一下Note实体类的toString方法然后在insert之后添加一条打印语句
Log.i(“插入的数据”, NoteApp.getInstnca().getDaoSession().getNoteDao().loadAll().toString());我们看下运行的结果

这里我添加了3个日记,确实都添加成功了.

6.我们实现主页面的列表

布局文件我就不放了,就是一个Recyclerview然后右下角有一个FloatingActionButton用来启动创建日记的按钮,看下Activity 的代码

public class MainActivity extends AppCompatActivity {    @BindView(R.id.toolbar)    Toolbar toolbar;    @BindView(R.id.notes)    RecyclerView notes;    @BindView(R.id.fab)    FloatingActionButton fab;    NoteAdapter noteAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ButterKnife.bind(this);        setSupportActionBar(toolbar);        notes.setLayoutManager(new LinearLayoutManager(this));        noteAdapter = new NoteAdapter();        notes.setAdapter(noteAdapter);    }    @Override    protected void onResume() {        super.onResume();        List<Note> notes = NoteApp.getInstnca().getDaoSession().getNoteDao().loadAll();        noteAdapter.setNotes(notes);    }    @OnClick(R.id.fab)    public void onClick() {        Intent intent = new Intent(this, CreateNoteActivity.class);        startActivity(intent);    }}

MainActivity最主要的代码是
List notes = NoteApp.getInstnca().getDaoSession().getNoteDao().loadAll();
到这里一个小小的记事本就完成了,是不是很简单?
看下最后App的主页面

7.接下来再实现一个删除的功能

我们在RecyclerView 的Adapter里面添加一个接口,

 public interface OnNoteListener {        void onNoteClick(Note note);        void onNoteLongClick(Note note);    }

这个很明显啦,就是单击的时候是对日记进行修改,长按的时候进行删除操作,我们看一下删除的回调方法

 @Override    public void onNoteLongClick(final Note note) {        AlertDialog.Builder builder = new AlertDialog.Builder(this);        builder.setTitle("提示信息");        builder.setTitle("确认删除吗?");        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialog, int which) {                NoteApp.getInstnca().getDaoSession().getNoteDao().delete(note);                List<Note> notes = NoteApp.getInstnca().getDaoSession().getNoteDao().loadAll();                noteAdapter.setNotes(notes);            }        });        builder.setNegativeButton("算了", null);        builder.create().show();    }

这个方法最主要的一句代码就是NoteApp.getInstnca().getDaoSession().getNoteDao().delete(note);通过指定的一个Note来删除数据,我们看下效果


我们看到这里确实删除成功了,好了至于修改的功能也难不倒哪去,照葫芦壶瓢呗,这里就不实现了.