# 数据库GreenDao框架
1.新创建Java实体类
~~~
@Entity(indexes = {
@Index(value = "text, date DESC", unique = true)
})
public class Note {
@Id
private Long id;
@NotNull
private String text;
private Date date;
}
~~~
2.Make Project
能生成三个文件，DaoMaster、DaoSession|、BeanDao
必须文件自己初始化那就是DaoSession，
3.自定义Application，获取DaoSession的实例化对象
注意true false的设置，设置为true，会报错，所以改为false
~~~
public class App extends Application {
/** A flag to show how easily you can switch from standard SQLite to the encrypted SQLCipher. */
public static final boolean ENCRYPTED = false;
private DaoSession daoSession;
@Override
public void onCreate() {
super.onCreate();
DevOpenHelper helper = new DevOpenHelper(this, ENCRYPTED ? "notes-db-encrypted" : "notes-db");
Database db = ENCRYPTED ? helper.getEncryptedWritableDb("super-secret") : helper.getWritableDb();
daoSession = new DaoMaster(db).newSession();
}
public DaoSession getDaoSession() {
return daoSession;
}
}
~~~
普通操作：插入、删除、更新、查找
4.完成插入Bean操作需要两步
第一步获取DaoSession对象
~~~
// get the note DAO
DaoSession daoSession = ((App) getApplication()).getDaoSession();
noteDao = daoSession.getNoteDao();
~~~
第二步，执行插入操作
~~~
Note note = new Note();
note.setText(noteText);
note.setComment(comment);
note.setDate(new Date());
note.setType(NoteType.TEXT);
noteDao.insert(note);
Log.d("DaoExample", "Inserted new note, ID: " + note.getId());
~~~
5.完成删除Bean操作需要两步
第一步同上
第二步，执行删除操作：
`noteDao.deleteByKey(id);`
7.更新Bean操作
第二步，执行更新曹组
~~~
note.setText("This note has changed.");
noteDao.update(note);
~~~
查找
~~~
noteDao.queryBuilder().orderAsc(NoteDao.Properties.Text).build();
private void queryEq() {
Son mingEq = sonDao.queryBuilder().where(SonDao.Properties.Name.eq("小明")).unique();
Log.d("mingEq", "queryEq() called" + mingEq);
}
~~~
8.设置数据库
~~~
DevOpenHelper helper = new DevOpenHelper(this, "notes-db");
Database db = helper.getWritableDb();
daoSession = new DaoMaster(db).newSession();
~~~
9.更新数据库
什么情况下更新？
新建数据表
数据表字段更新
如何更新？
方法1 创建新的数据库
方法2 待定
# Green文档，Sample 6个类
1.APP类
~~~
public class App extends Application {
/** A flag to show how easily you can switch from standard SQLite to the encrypted SQLCipher. */
public static final boolean ENCRYPTED = true;
private DaoSession daoSession;
@Override
public void onCreate() {
super.onCreate();
DevOpenHelper helper = new DevOpenHelper(this, ENCRYPTED ? "notes-db-encrypted" : "notes-db");
Database db = ENCRYPTED ? helper.getEncryptedWritableDb("super-secret") : helper.getWritableDb();
daoSession = new DaoMaster(db).newSession();
}
public DaoSession getDaoSession() {
return daoSession;
}
}
~~~
2.标注的实体类
~~~
import org.greenrobot.greendao.annotation.Convert;
import org.greenrobot.greendao.annotation.Entity;
import org.greenrobot.greendao.annotation.Generated;
import org.greenrobot.greendao.annotation.Id;
import org.greenrobot.greendao.annotation.Index;
import org.greenrobot.greendao.annotation.NotNull;
/**
* Entity mapped to table "NOTE".
*/
@Entity(indexes = {
@Index(value = "text, date DESC", unique = true)
})
public class Note {
@Id
private Long id;
@NotNull
private String text;
private String comment;
private java.util.Date date;
@Convert(converter = NoteTypeConverter.class, columnType = String.class)
private NoteType type;
@Generated(hash = 1272611929)
public Note() {
}
public Note(Long id) {
this.id = id;
}
@Generated(hash = 1686394253)
public Note(Long id, @NotNull String text, String comment, java.util.Date date, NoteType type) {
this.id = id;
this.text = text;
this.comment = comment;
this.date = date;
this.type = type;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
@NotNull
public String getText() {
return text;
}
/** Not-null value; ensure this value is available before it is saved to the database. */
public void setText(@NotNull String text) {
this.text = text;
}
public String getComment() {
return comment;
}
public void setComment(String comment) {
this.comment = comment;
}
public java.util.Date getDate() {
return date;
}
public void setDate(java.util.Date date) {
this.date = date;
}
public NoteType getType() {
return type;
}
public void setType(NoteType type) {
this.type = type;
}
}
~~~
# 实体类的枚举属性
~~~
public enum NoteType {
TEXT, LIST, PICTURE
}
~~~
# 转换器
import org.greenrobot.greendao.converter.PropertyConverter;
public class NoteTypeConverter implements PropertyConverter<NoteType, String> {
@Override
public NoteType convertToEntityProperty(String databaseValue) {
return NoteType.valueOf(databaseValue);
}
@Override
public String convertToDatabaseValue(NoteType entityProperty) {
return entityProperty.name();
}
}
# 数据库层主要用例Demo：
~~~
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.TextView.OnEditorActionListener;
import org.greenrobot.greendao.query.Query;
import java.text.DateFormat;
import java.util.Date;
import java.util.List;
public class NoteActivity extends AppCompatActivity {
private EditText editText;
private View addNoteButton;
private NoteDao noteDao;
private Query<Note> notesQuery;
private NotesAdapter notesAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setUpViews();
// get the note DAO
DaoSession daoSession = ((App) getApplication()).getDaoSession();
noteDao = daoSession.getNoteDao();
// query all notes, sorted a-z by their text
notesQuery = noteDao.queryBuilder().orderAsc(NoteDao.Properties.Text).build();
updateNotes();
}
private void updateNotes() {
List<Note> notes = notesQuery.list();
notesAdapter.setNotes(notes);
}
protected void setUpViews() {
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerViewNotes);
//noinspection ConstantConditions
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
notesAdapter = new NotesAdapter(noteClickListener);
recyclerView.setAdapter(notesAdapter);
addNoteButton = findViewById(R.id.buttonAdd);
//noinspection ConstantConditions
addNoteButton.setEnabled(false);
editText = (EditText) findViewById(R.id.editTextNote);
editText.setOnEditorActionListener(new OnEditorActionListener() {
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
if (actionId == EditorInfo.IME_ACTION_DONE) {
addNote();
return true;
}
return false;
}
});
editText.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
boolean enable = s.length() != 0;
addNoteButton.setEnabled(enable);
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void afterTextChanged(Editable s) {
}
});
}
public void onAddButtonClick(View view) {
addNote();
}
private void addNote() {
String noteText = editText.getText().toString();
editText.setText("");
final DateFormat df = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);
String comment = "Added on " + df.format(new Date());
Note note = new Note();
note.setText(noteText);
note.setComment(comment);
note.setDate(new Date());
note.setType(NoteType.TEXT);
noteDao.insert(note);
Log.d("DaoExample", "Inserted new note, ID: " + note.getId());
updateNotes();
}
NotesAdapter.NoteClickListener noteClickListener = new NotesAdapter.NoteClickListener() {
@Override
public void onNoteClick(int position) {
Note note = notesAdapter.getNote(position);
Long noteId = note.getId();
noteDao.deleteByKey(noteId);
Log.d("DaoExample", "Deleted note, ID: " + noteId);
updateNotes();
}
};
}
~~~
# Item适配器
~~~
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class NotesAdapter extends RecyclerView.Adapter<NotesAdapter.NoteViewHolder> {
private NoteClickListener clickListener;
private List<Note> dataset;
public interface NoteClickListener {
void onNoteClick(int position);
}
static class NoteViewHolder extends RecyclerView.ViewHolder {
public TextView text;
public TextView comment;
public NoteViewHolder(View itemView, final NoteClickListener clickListener) {
super(itemView);
text = (TextView) itemView.findViewById(R.id.textViewNoteText);
comment = (TextView) itemView.findViewById(R.id.textViewNoteComment);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (clickListener != null) {
clickListener.onNoteClick(getAdapterPosition());
}
}
});
}
}
public NotesAdapter(NoteClickListener clickListener) {
this.clickListener = clickListener;
this.dataset = new ArrayList<Note>();
}
public void setNotes(@NonNull List<Note> notes) {
dataset = notes;
notifyDataSetChanged();
}
public Note getNote(int position) {
return dataset.get(position);
}
@Override
public NotesAdapter.NoteViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.item_note, parent, false);
return new NoteViewHolder(view, clickListener);
}
@Override
public void onBindViewHolder(NotesAdapter.NoteViewHolder holder, int position) {
Note note = dataset.get(position);
holder.text.setText(note.getText());
holder.comment.setText(note.getComment());
}
@Override
public int getItemCount() {
return dataset.size();
}
}
~~~
