GreenDao的小小使用

//全布局的依赖

buildscript {    repositories {        jcenter()        mavenCentral()    }    dependencies {        classpath 'com.android.tools.build:gradle:2.3.1'        classpath 'org.greenrobot:greendao-gradle-plugin:3.2.1'    }}

App里的依赖

要先在顶上加

apply plugin: 'org.greenrobot.greendao'

然后加依赖

dependencies {    compile 'com.android.support:appcompat-v7:26.+'    compile 'com.android.support.constraint:constraint-layout:1.0.2'    testCompile 'junit:junit:4.12'    compile 'org.greenrobot:greendao:3.2.0'}

User类Bean类的书写要特别注意

@Entitypublic class User {    @Id(autoincrement = true)    private long id;    private String name;    @Generated(hash = 1144922831)    public User(long id, String name) {        this.id = id;        this.name = name;    }    @Generated(hash = 586692638)    public User() {    }    public long getId() {        return this.id;    }    public void setId(long id) {        this.id = id;    }    public String getName() {        return this.name;    }    public void setName(String name) {        this.name = name;    }}

MainActivity实现

public class MainActivity extends AppCompatActivity {    UserDao userDao;    private EditText etId;    private EditText etName;    private Button btnAdd;    private Button btnDelete;    private Button btnQuery;    private TextView tvQuery;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();        initDbHelp();        /*新增一条数据*/        btnAdd.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                String id = etId.getText().toString();                String name = etName.getText().toString();                if (isNotEmpty(id) && isNotEmpty(name)) {                    QueryBuilder qb = userDao.queryBuilder();                    ArrayList<User> list = (ArrayList<User>) qb.where(UserDao.Properties.Id.eq(id)).list();                    if (list.size() > 0) {                        Toast.makeText(MainActivity.this, "主键重复", Toast.LENGTH_SHORT).show();                    } else {                        userDao.insert(new User(Long.valueOf(id), name));                        Toast.makeText(MainActivity.this, "插入数据成功", Toast.LENGTH_SHORT).show();                    }                } else {                    if (isEmpty(id) && isNotEmpty(name)) {                        Toast.makeText(MainActivity.this, "id为空", Toast.LENGTH_SHORT).show();                    }                    if (isEmpty(name) && isNotEmpty(id)) {                        Toast.makeText(MainActivity.this, "姓名为空", Toast.LENGTH_SHORT).show();                    }                    if (isEmpty(id) && isEmpty(name)) {                        Toast.makeText(MainActivity.this, "请填写信息", Toast.LENGTH_SHORT).show();                    }                }                etId.setText("");                etName.setText("");            }        });        /*删除指定数据*/        btnDelete.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                String id = etId.getText().toString();                if (isNotEmpty(id)) {                    userDao.deleteByKey(Long.valueOf(id));                    QueryBuilder qb = userDao.queryBuilder();                    ArrayList<User> list = (ArrayList<User>) qb.where(UserDao.Properties.Id.eq(id)).list();                    if (list.size() < 1) {                        Toast.makeText(MainActivity.this, "删除数据成功", Toast.LENGTH_SHORT).show();                        etId.setText("");                        etName.setText("");                    }                } else {                    Toast.makeText(MainActivity.this, "id为空", Toast.LENGTH_SHORT).show();                }            }        });        /*查询数据*/        btnQuery.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                String id = etId.getText().toString();                if (isNotEmpty(id)) {                    QueryBuilder qb = userDao.queryBuilder();                    ArrayList<User> list = (ArrayList<User>) qb.where(UserDao.Properties.Id.eq(id)).list();                    if (list.size() > 0) {                        String text = "";                        for (User user : list) {                            text = text + "\r\n" + user.getName();                        }                        tvQuery.setText(text);                    } else {                        tvQuery.setText("");                        Toast.makeText(MainActivity.this, "不存在该数据", Toast.LENGTH_SHORT).show();                    }                    etId.setText("");                    etName.setText("");                } else {                    Toast.makeText(MainActivity.this, "id为空", Toast.LENGTH_SHORT).show();                }            }        });    }    /*初始化数据库相关*/    private void initDbHelp() {        DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(this, "recluse-db", null);        SQLiteDatabase db = helper.getWritableDatabase();        DaoMaster daoMaster = new DaoMaster(db);        DaoSession daoSession = daoMaster.newSession();        userDao = daoSession.getUserDao();    }    private void initView() {        etId = (EditText) findViewById(R.id.etId);        etName = (EditText) findViewById(R.id.etName);        btnAdd = (Button) findViewById(R.id.btnAdd);        btnDelete = (Button) findViewById(R.id.btnDelete);        btnQuery = (Button) findViewById(R.id.btnQuery);        tvQuery = (TextView) findViewById(R.id.tvQuery);    }    private boolean isNotEmpty(String s) {        if (s != null && !s.equals("") || s.length() > 0) {            return true;        } else {            return false;        }    }    private boolean isEmpty(String s) {        if (isNotEmpty(s)) {            return false;        } else {            return true;        }    }}

布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:layout_margin="10dp"        android:text="greenDao lib test"        android:textColor="@android:color/black" />    <EditText        android:id="@+id/etId"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="请输入用户id"        android:inputType="number"        android:textSize="15sp" />    <EditText        android:id="@+id/etName"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:hint="请输入用户名"        android:textSize="15sp" />    <Button        android:id="@+id/btnAdd"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="新增" />    <Button        android:id="@+id/btnDelete"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="删除" />    <Button        android:id="@+id/btnQuery"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="查询" />    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:layout_margin="10dp"        android:text="查询结果"        android:textColor="@android:color/black" />    <TextView        android:id="@+id/tvQuery"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_horizontal"        android:layout_margin="10dp"        android:textColor="@android:color/black" /></LinearLayout>