Android中Data Binding学习使用

1、官方文档

2、基本操作

关于DataBinding具体有什么优势和坑，网上资料太多了，这里只学习下怎么使用。
首先一个Model是必须的

public class UserInfo {
    private String name;
    private String age;
    private String provice;
    private String country;

    public UserInfo(String name, String age, String provice, String country) {
        this.name = name;
        this.age = age;
        this.provice = provice;
        this.country = country;
    }

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getProvice() {
        return provice;
    }

    public void setProvice(String provice) {
        this.provice = provice;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public String getAddress() {
        return provice + country;
    }
}

Model和xml绑定

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

    <data>
        <variable
            name="user"
            type="com.study.databinding.model.UserInfo" />
    </data>

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{user.name}" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{user.address}" />
    </LinearLayout>
</layout>

和具体对象绑定

public class MainFragment extends Fragment{

    public static MainFragment newInstance(){
        MainFragment fragment = new MainFragment();
        return fragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        FragmentMainBinding binding = DataBindingUtil.inflate(inflater,R.layout.fragment_main,container,false);
        View rootView = binding.getRoot();

        UserInfo userInfo = new UserInfo("张三","45","江苏省苏州市","苏州工业园区");
        binding.setUser(userInfo);

        return rootView;
    }
}

脚本配置

android {
    ....
    dataBinding {
        enabled = true
    }
}

3、两种对事件处理的方式

3.1 Method References方式：把相关View事件交给指定的方法来完成响应。

<data>
        <variable
            name="user"
            type="com.study.databinding.model.UserInfo" />

        <variable
            name="eventHandler"
            type="com.study.databinding.MainFragment" />
    </data>

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        FragmentMainBinding binding = DataBindingUtil.inflate(inflater,R.layout.fragment_main,container,false);
        View rootView = binding.getRoot();

        UserInfo userInfo = new UserInfo("张三","45","江苏省苏州市","苏州工业园区");
        binding.setUser(userInfo);
        binding.setEventHandler(this);
        return rootView;
    }

public void onNameClick(View view){
        Log.v("wwwwwwwwwweeeeeeeeeeeee","Name is Clicked");
    }

    public void onAddressClick(View view){
        Log.v("wwwwwwwwwweeeeeeeeeeeee","Address is Clicked");
    }

3.2 Listener Bindings

这种事件绑定和处理方式基本上和Method Reference类似，只不过它比Method Reference好的地方在于，事件处理者能够接收任意的数据。这种事件处理方式要求gradle版本为2.0及以上。

public class EventParams {
    private String name;
    private String address;

    public EventParams(String name, String address) {
        this.name = name;
        this.address = address;
    }

    public String getName() {
        return name;
    }

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

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "EventParams{" +
                "name='" + name + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

<variable
            name="eventParams"
            type="com.study.databinding.model.EventParams" />

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        FragmentMainBinding binding = DataBindingUtil.inflate(inflater,R.layout.fragment_main,container,false);
        View rootView = binding.getRoot();

        UserInfo userInfo = new UserInfo("张三","45","江苏省苏州市","苏州工业园区");
        binding.setUser(userInfo);
        binding.setEventHandler(this);
        binding.setEventParams(new EventParams("张三","qqqqqq"));
        return rootView;
    }

public void onSaveAddress(EventParams params){
        Log.v("wwwwwwwwwweeeeeeeeeeeee",""+ params.toString());
    }

4、对象刷新

这个应该是DataBinding的一大亮点了，在对象里面数据发生改变的时候可以自动刷新UI。数据刷新有三种方式：

4.1 Observable Objects 对整个对象都进行监听刷新

package com.study.databinding.model;

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

import com.study.databinding.BR;


/**
 * Created by luozheng on 2016/10/13.
 */

public class UserInfo extends BaseObservable{
    private String name;
    private String age;
    private String provice;
    private String country;
    private String email;

    public UserInfo(String name, String age, String provice, String country) {
        this.name = name;
        this.age = age;
        this.provice = provice;
        this.country = country;
    }

    @Bindable
    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
        notifyPropertyChanged(BR.email);
    }

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

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

    @Bindable
    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
        notifyPropertyChanged(BR.age);
    }

    public String getProvice() {
        return provice;
    }

    public void setProvice(String provice) {
        this.provice = provice;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    @Bindable
    public String getAddress() {
        return provice + country;
    }
    public void setAddress(String address) {
        notifyPropertyChanged(BR.address);
    }

    @Override
    public String toString() {
        return "UserInfo{" +
                "name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", provice='" + provice + '\'' +
                ", country='" + country + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

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

    <data>
        <variable
            name="user"
            type="com.study.databinding.model.UserInfo" />

        <variable
            name="eventHandler"
            type="com.study.databinding.MainFragment" />

        <variable
            name="eventParams"
            type="com.study.databinding.model.UserInfo" />
    </data>

    <LinearLayout
        android:layout_margin="30dip"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:textSize="30sp"
            android:layout_margin="20dip"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="@{eventHandler::onNameClick}"
            android:text="@{user.name}" />

        <TextView
            android:textSize="30sp"
            android:layout_margin="20dip"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="@{() -> eventHandler.onSaveAddress(eventParams)}"
            android:text="@{user.address}" />

        <TextView
            android:textSize="30sp"
            android:layout_margin="20dip"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:hint="邮箱地址信息"
            android:text="@{user.email}" />

        <EditText
            android:id="@+id/editEmail"
            android:textSize="30sp"
            android:layout_margin="20dip"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

        <Button
            android:textSize="30sp"
            android:layout_margin="20dip"
            android:text="数据刷新"
            android:onClick="@{eventHandler::onRefresh}"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </LinearLayout>
</layout>

public class MainFragment extends Fragment{

    FragmentMainBinding dataBinding;
    UserInfo userInfo;
    EditText editEmail;


    public static MainFragment newInstance(){
        MainFragment fragment = new MainFragment();
        return fragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        dataBinding = DataBindingUtil.inflate(inflater,R.layout.fragment_main,container,false);
        View rootView = dataBinding.getRoot();
        editEmail = (EditText) rootView.findViewById(R.id.editEmail);

        userInfo = new UserInfo("张三","45","江苏省苏州市","苏州工业园区");
        dataBinding.setUser(userInfo);
        dataBinding.setEventHandler(this);
        dataBinding.setEventParams(userInfo);
        return rootView;
    }

    public void onNameClick(View view){
        Log.v("wwwwwwwwwweeeeeeeeeeeee","Name is Clicked");
    }

    public void onAddressClick(View view){
        Log.v("wwwwwwwwwweeeeeeeeeeeee","Address is Clicked");
    }

    public void onSaveAddress(UserInfo params){
        Log.v("wwwwwwwwwweeeeeeeeeeeee",""+ params.toString());
    }

    public void onRefresh(View view){
        userInfo.setName("张君宝");
        userInfo.setEmail(editEmail.getText().toString());
    }
}

4.2 ObservableFields 只对特定的属性进行监听刷新（略）

4.3 Observable Collections 集合类数据类型刷新（略）

5、控件with id后可以直接从bingding里面获取到了，不用通过findviewbyid来获取了，也不需要借助第三方注解框架了。

6、数据双向绑定

数据双向绑定参考一
数据双向绑定参考二
InverseBindingMethod