(补)databind 不写adapter和viewholder了

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前几天写了DataBind 不写adapter和viewholder了在掘金上吸取了几位大佬的建议,所以这篇文章主要是补充上文的,建议没有看过的可以考虑看一看。好了进入正文:

bean的复用

由于上次实现把layout和bean绑定一起了这就导致了bean的复用性很差,而且当只是让bean承担实体的作用时 bean会有额外的职责,很不符合单一职责原则,感谢大佬们的提醒

我的解决方案

怎么解决这个问题呢?我的解决方案很简单 就是加了一个wrapper.简单的来说,就是将实体注入wrapper,wrapper持有一个bean对象,那么layout里就可以操作bean了,同时ui的交互也交给了wrapper,保证了bean类的纯净

具体实现(主要都是贴代码)

这里由于BindAdapterType接口不是很适合需求然后我就删除了,取而代之的是LayoutWrapper

public interface LayoutWrapper<T> {

    /**
     * @param t 适应的目标
     * @return this
     */
    LayoutWrapper setTarget(T t);

    /**
     * @return 适应的目标
     */
    T getTarget();

    /**
     * @return layoutId
     */
    int getType();

    /**
     * @return layout中的 BR.id
     */
    int getId();
}

为了方便阅读 这里我就多贴一些代码

实体

public class UserInfo{
    private String name;
    private String age;
    private String avator;
    //省略set/get 
    public UserInfo(String name, String age, String avator) {
        this.name = name;
        this.age = age;
        this.avator = avator;
    }
}

public class StudentInfo{
    private String name;
    private String age;
    private String avator;
    //省略set/get 
    public StudentInfo(String name, String age, String avator) {
        this.name = name;
        this.age = age;
        this.avator = avator;
    }
}

wrapper

//userItemWrapper
public class UserItemWrapper implements LayoutWrapper<UserInfo> {
    private UserInfo userInfo;

    @Override
    public UserItemWrapper setTarget(UserInfo userInfo) {
        this.userInfo = userInfo;
        return this;
    }

    @Override
    public UserInfo getTarget() {
        return userInfo;
    }

    @Override
    public int getType() {
        return R.layout.user_item;
    }

    @Override
    public int getId() {
        return BR.user;
    }

    @BindingAdapter("avator")
    public static void setUserInfoAvtor(ImageView imageView, String avator) {
        Glide.with(imageView.getContext()).load(avator).into(imageView);
    }

    public void clickParent(View view) {
        Toast.makeText(view.getContext(), "福步距", Toast.LENGTH_SHORT).show();
    }

    public void clickImage(View view) {
        Toast.makeText(view.getContext(), "ImageView", Toast.LENGTH_SHORT).show();
    }
}


//studentItemWrapper

public class StudentItemWrapper implements LayoutWrapper<StudentInfo> {
    private StudentInfo studentInfo;

    @Override
    public StudentItemWrapper setTarget(StudentInfo studentInfo) {
        this.studentInfo = studentInfo;
        return this;
    }

    @Override
    public StudentInfo getTarget() {
        return studentInfo;
    }

    @Override
    public int getType() {
        return R.layout.student_item;
    }

    @Override
    public int getId() {
        return BR.student;
    }


    @BindingAdapter("avator")
    public static void setUserInfoAvtor(ImageView imageView, String avator) {
        Glide.with(imageView.getContext()).load(avator).into(imageView);
    }

    public void clickParent(View view) {
        Toast.makeText(view.getContext(), "福步距", Toast.LENGTH_SHORT).show();
    }

    public void clickImage(View view) {
        Toast.makeText(view.getContext(), "ImageView", Toast.LENGTH_SHORT).show();
    }
}

layout

//user_item
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>

        <variable
            name="user"
            type="com.google.simple.model.wrapper.UserItemWrapper"
            />
    </data>

    <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="@{user.clickParent}"
        android:padding="9dp">

        <ImageView
            android:id="@+id/avator"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:onClick="@{user.clickImage}"
            app:avator="@{user.target.avator}"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/name"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:gravity="center"
            android:text="@{user.target.name??`zhangsan`}"
            android:textSize="14sp"
            app:layout_constraintLeft_toRightOf="@id/avator"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/age"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:gravity="center"
            android:text="@{user.target.age}"
            android:textSize="14sp"
            app:layout_constraintBottom_toBottomOf="@id/avator"
            app:layout_constraintLeft_toRightOf="@id/avator"
            app:layout_constraintTop_toBottomOf="@id/name" />
    </android.support.constraint.ConstraintLayout>
</layout>

//studentItem
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>

        <variable
            name="student"
            type="com.google.simple.model.wrapper.StudentItemWrapper" />
    </data>

    <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="@{student.clickParent}"
        android:padding="9dp">

        <ImageView
            android:id="@+id/student_avator"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:onClick="@{student.clickImage}"
            app:avator="@{student.target.avator}"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/student_name"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:gravity="center"
            android:text="@{student.target.name??`zhangsan`}"
            android:textColor="#f00"
            android:textSize="14sp"
            app:layout_constraintLeft_toRightOf="@id/student_avator"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/student_age"
            android:layout_width="80dp"
            android:layout_height="40dp"
            android:gravity="center"
            android:text="@{student.target.age}"
            android:textColor="#f00"
            android:textSize="14sp"
            app:layout_constraintBottom_toBottomOf="@id/student_avator"
            app:layout_constraintLeft_toRightOf="@id/student_avator"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toBottomOf="@id/student_name" />
    </android.support.constraint.ConstraintLayout>
</layout>

这样bean的复用就解决了

具体操作与上一篇类似(注意两种方案天生支持多类型) 这里有个代码地址 simple

思考

虽然我们把adapter和viewholder省掉了 但是我们多了一个LayoutWrapper,LayoutWrapper牵扯到具体的ui交互,也就是说不能通过注解来解决(尽管我们可以自定义注解将接口的代码省去,但是并不能解决根本问题),那么这么做到底值不值得呢?我个人觉得 应该是值得的,首先adapter和Viewholder是两个类吧,我们用一个wrapper代替,其次wrapper配合databind+google新架构 数据刷新、设置等操作不用手写了,这样也就少写很多代码了。以上只是个人看法,如有建议欢迎评论 多谢指教 (0.0)