android 代替枚举

核心工具：IntDef和StringDef官方注解

compile 'com.android.support:support-annotations:22.0.0'

原理：编译期的类型检查

定义：

    public static final int Relationship_User = 0;// 陌生人
    public static final int Relationship_Friend = 1;// 通讯录好友
    public static final int Relationship_Requesting = 2;// 已发送好友请求
    @IntDef({Relationship_User, Relationship_Friend,Relationship_Requesting})
    @Retention(RetentionPolicy.SOURCE)
    public @interface Relationship {
    }

使用

    @Relationship
    private int relationship;

    @Relationship
    public int getRelationship() {
        return relationship;
    }

    public void setRelationship(@Relationship int relationship) {
        this.relationship = relationship;
    }
    
    void xxx(){
        this.setRelationship(1);// 有警告
        if (this.getRelationship() == 1){}// 有警告

        this.setRelationship(Relationship_User);// 没有
        if (this.getRelationship() == Relationship_User);// 没有
    }

完整的代码如下

    public class KapModelMessage extends KapModelBase {
    public static final int Relationship_User = 0;// 陌生人
    public static final int Relationship_Friend = 1;// 通讯录好友
    public static final int Relationship_Requesting = 2;// 已发送好友请求
    @IntDef({Relationship_User, Relationship_Friend,Relationship_Requesting})
    @Retention(RetentionPolicy.SOURCE)
    public @interface Relationship {
    }
    @Relationship
    private int relationship;

    @Relationship
    public int getRelationship() {
        return relationship;
    }

    public void setRelationship(@Relationship int relationship) {
        this.relationship = relationship;
    }

    void xxx(){
        this.setRelationship(1);// 有警告
        if (this.getRelationship() == 1){}// 有警告

        this.setRelationship(Relationship_User);// 没有
        if (this.getRelationship() == Relationship_User);// 没有
    }
}