DataBinding使用介绍

1. DataBinding使用

build.gradle中添加
dataBinding {
    enabled true
}

2. 创建JavaBean对象

public class User extends BaseObservable{
    private String name;
    private String phone;
    public int isHandSome;

    public User(String name,String phone){
        this.name = name;
        this.phone = phone;
    }


    @Bindable
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
        notifyPropertyChanged(BR.name);
    }

    @Bindable
    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
        notifyPropertyChanged(BR.phone);
    }
}

3.创建布局文件

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

        <import type="android.view.View"/>
        <import type="java.util.ArrayList"/>
        <import type="java.util.Map"/>
        <variable
            name="user"
            type="com.zlc.mvvm.User"/>

        <variable
            name="age"
            type="String"/>

        <variable
            name="list"
            type="ArrayList&lt;String>"/>

        <variable
            name="map"
            type="Map&lt;String,String>"/>

        <variable
            name="handler"
            type="com.zlc.mvvm.EventHandler"/>
    </data>

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="10dp">

        <TextView
            android:id="@+id/id_tv1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{user.name}"
            android:paddingBottom="10dp"/>


        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{age}"
            android:layout_marginTop="10dp"/>

        <TextView
            android:id="@+id/id_tv3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{user.isHandSome == 0 ? @string/hand1 : @string/hand2}"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"/>

        <include layout="@layout/phone_layout"
            bind:user="@{user}"
            />

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{list[1]}"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"/>

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text='@{map["name"]}'
            android:layout_marginBottom="10dp"
            android:onClick="@{handler.handOnClick}"
            />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="点我点我"
            android:onClick="@{handler.handOnClick}"/>

    </LinearLayout>
</layout>

4.简单赋值使用

新建变量值 user 导入User类型
<variable
    name="user"
    type="com.zlc.mvvm.User"/>

<TextView
    android:id="@+id/id_tv1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@{user.name}"
    android:paddingBottom="10dp"/>

代码中使用
ActivityMainBinding dataBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);
User user = new User("zlc","18684732678");
user.isHandSome = 0;
dataBinding.setUser(user);

5.变量赋值

 <variable
     name="age"
     type="String"/>

<TextView
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:text="@{String.valueOf(age)}"
     android:layout_marginTop="10dp"/>

dataBinding.setAge(25);

6. inclue加载布局


两个布局里面都需要有
<variable
    name="user"
    type="com.zlc.mvvm.User"/>
新布局

<?xml version="1.0" encoding="utf-8"?>
<layout>
    <data>
        <variable
            name="user"
            type="com.zlc.mvvm.User"/>
    </data>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/id_tv2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{user.phone}"/>

    </LinearLayout>
</layout>

<include layout="@layout/phone_layout"
         bind:user="@{user}"/>

7. 引用资源文件的值

<resources>
    <string name="app_name">MVVMProject</string>
    <string name="hand1">帅</string>
    <string name="hand2">帅而且有钱</string>
</resources>

<TextView
     android:id="@+id/id_tv3"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:text="@{user.isHandSome == 0 ? @string/hand1 : @string/hand2}"
     android:layout_marginTop="10dp"
     android:layout_marginBottom="10dp"/>

8. import导入

<import type="android.view.View"/>

<TextView
     android:id="@+id/id_tv3"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:text="@string/hand2}"
android:visibility="@{user.isHandSome == 0 ? View.VISIBLE : View.GONE}""
     android:layout_marginTop="10dp"
     android:layout_marginBottom="10dp"/>

9. List集合使用

<import type="java.util.ArrayList"/>
不能出现< 用&lt;替代
<variable
    name="list"
    type="ArrayList&lt;String>"/>

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@{list[1]}"
    android:layout_marginTop="10dp"
    android:layout_marginBottom="10dp"/>

    ArrayList list = new ArrayList();
    list.add("哈哈哈");
    list.add("嘻嘻嘻");
    list.add("呵呵呵");
    dataBinding.setList(list);

10. Map集合使用

<import type="java.util.Map"/>
<variable
    name="map"
    type="Map&lt;String,String>"/>

//根据key取value
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text='@{map["name"]}'
    android:layout_marginBottom="10dp"
    android:onClick="@{handler.handOnClick}"
    />

Map map = new HashMap();
map.put("name","hhhzlc");
dataBinding.setMap(map);

11. 事件绑定

public void onClick(View view){
    user.setName("郑乐成");
    user.setPhone("18888888888");     Toast.makeText(this,"zqwxhni",Toast.LENGTH_LONG).show();
}

<variable
    name="click"
    type="com.zlc.mvvm.MainActivity"/>

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="点我点我"
    android:onClick="@{click.onClick}"/>

 dataBinding.setClick(this);

12. 通过Observable的方式去通知UI数据已经改变

官方为我们提供了更加简便的方式BaseObservable，我们的实体类只需要继承该类，稍做几个操作，就能轻松实现数据变化的通知。如何使用呢？ 首先我们的实体类要继承BaseObservale类，第二步在Getter上使用注解@Bindable，第三步，在Setter里调用方法notifyPropertyChanged，第四步，完成

    package com.zlc.mvvm;

    import android.databinding.BaseObservable;
    import android.databinding.Bindable;

    /**
     * Created by Administrator on 2017/10/21.
     */

    public class User extends BaseObservable{

        private String name;
        private String phone;
        public int isHandSome;

        public User(String name,String phone){
            this.name = name;
            this.phone = phone;
        }

        @Bindable
        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
            notifyPropertyChanged(BR.name);
        }

        @Bindable
        public String getPhone() {
            return phone;
        }

        public void setPhone(String phone) {
            this.phone = phone;
            notifyPropertyChanged(BR.phone);
        }
    }

     public void onClick(View view){
        user.setName("郑乐成");
        user.setPhone("18888888888");
      Toast.makeText(this,"zqwxhni",Toast.LENGTH_LONG).show();
    }

    dataBinding.setClick(this);

13. Inflate

ViewDataBinding binding = DataBindingUtil.inflate(inflate,layoutId,viewGroup,attachToParent)；
     View view = inflate.getRoot();  //获取view对象

14. DataBinding VS RecyclerView VS ListView

item布局
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="user"
            type="com.zlc.mvvm.User" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:gravity="center_vertical">

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@{user.name}"
            android:layout_alignParentLeft="true"
            android:gravity="center"
            />

        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@{user.phone}"
            android:layout_alignParentRight="true"
            android:gravity="center"/>

    </LinearLayout>
</layout>

适配器

public class MyAdapter extends  RecyclerView.Adapter<MyAdapter.MyHolder>{

        private ArrayList<User> mData;
        private Context mContext;
        public MyAdapter(Context context, ArrayList<User> data) {
            this.mContext = context;
            this.mData = data;
        }


        @Override
        public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {

            ViewDataBinding binding = DataBindingUtil.inflate(LayoutInflater.from(mContext), R.layout.list_item, parent, false);
            MyHolder holder = new MyHolder(binding.getRoot());
                holder.setBinding(binding);
                return holder;
        }

        @Override
        public void onBindViewHolder(MyHolder holder, int position) {
                    holder.getBinding().setVariable(BR.user,mData.get(position));
                holder.getBinding().executePendingBindings();
        }

        @Override
        public int getItemCount() {
            return mData.size();
        }

        public class MyHolder extends RecyclerView.ViewHolder{

              private ViewDataBinding binding;
              public MyHolder(View itemView) {
                super(itemView);
        }

        public void setBinding(ViewDataBinding binding) {
             this.binding = binding;
        }

       public ViewDataBinding getBinding() {
             return binding;
       }
    }
}

15.自定义setter(BindingAdapter)

<layout xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:app="http://schemas.android.com/apk/res-auto">  
        <data class=".Custom">  
            <variable  
                name="imageUrl"  
                type="String" />  
        </data>  

        <ImageView  
            android:layout_width="match_parent"  
            android:layout_height="wrap_content"  
            app:imageUrl="@{imageUrl}"/>  
</layout>

 binding.setImageUrl("http://images.csdn.net/20150810/Blog-Image%E5%89%AF%E6%9C%AC.jpg");  


@BindingAdapter({"bind:imageUrl"})  
public static void imageLoader(ImageView imageView, String url) {  
        ImageLoaderUtils.getInstance().displayImage(url, imageView);  
}

16. Converters

Converter是什么呢？举个例子吧：假如你的控件需要一个格式化好的时间，但是你只有一个Date类型额变量咋办？肯定有人会说这个简单，转化完成后在设置，恩，这也是一种办法，但是DataBinding还给我们提供了另外一种方式，虽然原理一样，但是这种方式使用的场景更多，那就是——Converter

    <layout xmlns:android="http://schemas.android.com/apk/res/android">  
        <data class=".Custom">  
            <variable  
                name="time"  
                type="java.util.Date" />  
        </data>  

        <TextView  
            android:layout_width="match_parent"  
            android:layout_height="wrap_content"  
            android:text="@{time}"/>  
    </layout>

    binding.setTime(new Date());  

    @BindingConversion
       public static String convertDate(Date date) {
           SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
           return sdf.format(date);
    }

DataBinding使用介绍

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