Data Binding官方文档
Data Binding官方文档-翻译
Data Binding官方文档-实例
1. 基本结构
1.1 JavaBeans对象
public class User {
private final String firstName;
public User(String firstName) {
this.firstName = firstName;
}
public String getFirstName() {
return this.firstName;
}
}
1.2 布局文件
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="user" type="com.example.User"/>
</data>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@{user.firstName}"/>
</LinearLayout>
</layout>
1.3 Activity
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity);
User user = new User("Test");
binding.setUser(user);
}
以上三步完成了基本数据绑定
2. 动态更新
当JavaBean对象的数据发生变化时,View自动更新。
正常的数据源只能做到绑定,想要动态更新,就必须要用Observable的方式存储数据,以下是实现Observable的三种方式。
2.1 Observable 对象
实现android.databinding.Observable或继承其实现类
private static class User extends BaseObservable {
private String firstName;
@Bindable
public String getFirstName() {
return this.firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
notifyPropertyChanged(BR.firstName);
}
}
2.2 Observable 字段
基本的数据类型都有相应的Observable类
public final ObservableField<String> firstName = new ObservableField<>();
2.3 Observable 集合
ObservableArrayMap<String, Object> mapUser = new ObservableArrayMap<>();
user.put("firstName", "Google");
2.4 引用
无论是对象、字段还是集合,都是以Observable的方式存储数据。接下来就是在布局中引用了。
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<import type="android.databinding.ObservableMap" />
<variable name="user" type="com.example.ObservableUser" />
<variable name="firstName" type="android.databinding.ObservableField" />
<variable name="mapUser" type="ObservableMap<String, Object>" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- Observable 对象 -->
<TextView
android:text="@{user.firstName}"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<!-- Observable 字段 -->
<TextView
android:text="@{firstName.get()}"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<!-- Observable 集合 -->
<TextView
android:text="@{mapUser[`firstName`]}"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</layout>
3. RecyclerView动态绑定
private static class RecyclerViewAdapter
extends RecyclerView.Adapter<RecyclerViewAdapter.BindingHolder> {
private List<Model> mModels;
public static class BindingHolder extends RecyclerView.ViewHolder {
private final ViewDataBinding binding;
public BindingHolder(ViewDataBinding binding) {
super(binding.getRoot());
this.binding = binding;
// 这里可以binding.getRoot().findViewById,然后再onBindViewHolder中绑定事件,目前没有找到更方便的方法
}
public ViewDataBinding getBinding() {
return binding;
}
}
@Override
public BindingHolder onCreateViewHolder(ViewGroup parent, int viewType) {
ViewDataBinding binding = DataBindingUtil.inflate(
LayoutInflater.from(parent.getContext()),
R.layout.list_item,
parent,
false);
BindingHolder holder = new BindingHolder(binding);
return holder;
}
@Override
public void onBindViewHolder(final BindingHolder holder, int position) {
final Model model = mModels.get(position);
holder.getBinding().setVariable(BR.model, model);
holder.getBinding().getRoot().setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
}
});
holder.getBinding().executePendingBindings();
}
@Override
public int getItemCount() {
return mModels.size();
}
}
**粗体** _斜体_ [链接](http://example.com) `代码` - 列表 > 引用
。你还可以使用@
来通知其他用户。