GreenDao与ReactiveX的完美搭配，greendaoreactivex

GreenDao与ReactiveX的完美搭配，greendaoreactivex

转载请注明出处：http://www.cnblogs.com/cnwutianhao/p/6719380.html 

作为Android开发者，一定不会对 GreenDao 和 ReactiveX 陌生。

GreenDao   号称Android最快的关系型数据库

ReactiveX    Rx是一个编程模型,目标是提供一致的编程接口,帮助开发者更方便的处理异步数据流。

下面我们就通过一个实例，来讲解有无Rx支持的时候GreenDao应该怎么用，实现增删操作。

首先导入需要的库(本文针对的 GreenDao 是 3.x 版本， Rx 是 1.x 版本)

GreenDao导入需求库的说明: https://github.com/greenrobot/greenDAO/

在 build.gradle(Project:Xxx) 下，添加：

buildscript {
    repositories {
        ...
        mavenCentral()
        ...
    }
    dependencies {
        ...
        classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'
        ...
    }
}

在 build.gradle(Module:Xxx) 下，添加：

...
apply plugin: 'org.greenrobot.greendao'
...
dependencies {
    ...
    compile 'org.greenrobot:greendao:3.2.2'
    ...
}

Rx导入需求库的说明: https://github.com/ReactiveX/RxJava/tree/1.x

在 build.gradle(Module:Xxx) 下，添加：

dependencies {
    ...
    compile 'io.reactivex:rxjava:1.2.9'
    compile 'io.reactivex:rxandroid:1.2.1'
    ...
}

需求库添加完之后就可以进入正题了

1.参考GreenDao官方文档，添加必要的类 Note 、 NotesAdapter 、 NoteType 、 NoteTypeConverter

Note :

/**
 * 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;
    }

}

NotesAdapter :

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();
    }
}

NoteType :

public enum NoteType {
    TEXT, LIST, PICTURE
}

NoteTypeConverter :

public class NoteTypeConverter implements PropertyConverter<NoteType, String> {
    @Override
    public NoteType convertToEntityProperty(String databaseValue) {