Android dataBinding 的綁定數(shù)據(jù)琅束、列表洞渔、點(diǎn)擊事件等使用

dataBinding是google推出來的一個(gè)mvvm的框架输吏，出來有一段時(shí)間了权旷，由于之前的項(xiàng)目都是用mvc或者mvp的模式開發(fā)，沒有使用mvvm模式進(jìn)行開發(fā)贯溅，這次公司項(xiàng)目用的是jetpack框架拄氯，涉及到ViewModel、dataBinding等它浅，所以就利用些空閑時(shí)間了解和學(xué)習(xí)下dataBinding的一些使用译柏。

準(zhǔn)備工作：

要使用dataBinding的話，首先要在app model 下build.gradle文件的android節(jié)點(diǎn)下添加

dataBinding{
        enabled=true
    }

如：

image

數(shù)據(jù)綁定

在xml布局中使用dataBinding時(shí)罚缕，要將xml布局文件的節(jié)點(diǎn)進(jìn)行修改艇纺，如：

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

    </data>

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

    </LinearLayout>
</layout>

將layout節(jié)點(diǎn)放最外面怎静，接著是data節(jié)點(diǎn)邮弹，在data節(jié)點(diǎn)中可以新增variable節(jié)點(diǎn)，在data節(jié)點(diǎn)下面可以寫之前的布局節(jié)點(diǎn)蚓聘；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="employee"
            type="com.lsm.databindingtest.Employee" />
    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:id="@+id/first_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="10dp"
            android:text="@{employee.firstName}" />
        <TextView
            android:id="@+id/last_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="10dp"
            android:text="@{employee.lastName}" />
    </LinearLayout>
</layout>

variable節(jié)點(diǎn)中name是type的一個(gè)名稱腌乡，type是對應(yīng)model類的包名路徑，通過@{}的方式對TextView進(jìn)行賦值夜牡；在activity文件中通過DataBindingUtil進(jìn)行引用与纽；

public class SimpleActivity extends AppCompatActivity {
    private ActivitySimpleBinding binding;
    private Employee employee = new Employee("Zhai", "Mark");
    private Worker worker = new Worker("1111", "2222");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = DataBindingUtil.setContentView(this, R.layout.activity_simple);
        //通過直接賦值
//        binding.firstName.setText(employee.getFirstName());
//        binding.lastName.setText(employee.getLastName());
//        binding.setEmployee(employee);
        binding.setVariable(BR.employee, employee);
    }
}

ActivitySimpleBinding命名：布局文件名稱(第一字母大寫侣签，遇到，去掉并將首字母大寫)+Binding;
這里賦值有三種方式：

1急迂、通過ActivitySimpleBinding.控件id影所，直接賦值;
如：binding.firstName.setText(employee.getFirstName());

2、ActivitySimpleBinding調(diào)用set方法;
如：binding.setEmployee(employee);

3僚碎、ActivitySimpleBinding調(diào)用setVariable方法;
binding.setVariable(BR.employee, employee);

image

事件綁定

事件可以通過方法或者監(jiān)聽器的形式來實(shí)現(xiàn)猴娩；
在對應(yīng)的activity中聲明一個(gè)事件的內(nèi)部類，在內(nèi)部類中定義對應(yīng)的事件方法勺阐，在xml布局中通過新增variable節(jié)點(diǎn)卷中，對它的name和type屬性進(jìn)行設(shè)置，也是用過@{}的方式綁定事件渊抽；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="eventlistener"
            type="com.lsm.databindingtest.SimpleActivity.EventListener" />
    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:onClick="@{eventlistener.clickFirst}"
            android:text="點(diǎn)擊(方法)" />
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:onClick="@{(view)->eventlistener.btnClick(view)}"
            android:text="點(diǎn)擊(監(jiān)聽器)" />
        <Button
            android:id="@+id/longc"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:onLongClick="@{eventlistener::onLongClick}"
            android:text="長按" />
    </LinearLayout>
</layout>

public class SimpleActivity extends AppCompatActivity {
    private ActivitySimpleBinding binding;
    private Employee employee = new Employee("Zhai", "Mark");
    private Worker worker = new Worker("1111", "2222");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = DataBindingUtil.setContentView(this, R.layout.activity_simple);
        binding.setEventlistener(new EventListener());
    }
    public class EventListener {
        public void clickFirst(View view) {
            worker.setFirstName("55555");
            worker.setLastName("7777777");
            Toast.makeText(SimpleActivity.this, "點(diǎn)擊了并刷新worker對象的值", Toast.LENGTH_LONG).show();
        }
        public void btnClick(View view){
            Toast.makeText(SimpleActivity.this, "監(jiān)聽器方式", Toast.LENGTH_LONG).show();
        }
        public boolean onLongClick(View view) {
            Toast.makeText(SimpleActivity.this, "長按了", Toast.LENGTH_LONG).show();
            return false;
        }
    }
}

activity中通過setEventlistener方法傳入EventListener對象蟆豫，setEventlistener方法是自動(dòng)生成的就可以了；在定義事件方法名稱時(shí)需要注意：方法的名稱可以和之前寫法不一樣懒闷，但是方法名稱的參數(shù)要和之前的寫法一樣十减，不然會(huì)報(bào)錯(cuò)，比如：clickFirst(View view)必須要有view參數(shù)愤估，如果沒有會(huì)報(bào)錯(cuò)

image

BaseObservable

BaseObservable在數(shù)據(jù)發(fā)生改變時(shí)通知xml布局試圖進(jìn)行刷新

public class Worker extends BaseObservable {
    private String mLastName;
    private String mFirstName;
    private boolean mIsFired=false;

    public Worker(String mLastName, String mFirstName) {
        this.mLastName = mLastName;
        this.mFirstName = mFirstName;
    }
    @Bindable
    public String getLastName() {
        return mLastName;
    }

    public void setLastName(String mLastName) {
        this.mLastName = mLastName;
        notifyPropertyChanged(BR.lastName);
    }
    @Bindable
    public String getFirstName() {
        return mFirstName;
    }

    public void setFirstName(String mFirstName) {
        this.mFirstName = mFirstName;
        notifyPropertyChanged(BR.firstName);
    }
    @Bindable
    public boolean getFired() {
        return mIsFired;
    }

    public void setFired(boolean mIsFired) {
        this.mIsFired = mIsFired;
        //刷新所有有關(guān)的ui
//        notifyChange();
    }
}

定義一個(gè)model類繼承自BaseObservable嫉称，在get方法上添加@Bindable注解，在set方法中notifyPropertyChanged(BR.lastName)方法更新指定的視圖灵疮，通過notifyChange();方法更新所有的視圖织阅，即使數(shù)據(jù)沒有更新也會(huì)重新刷新視圖；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="eventlistener"
            type="com.lsm.databindingtest.SimpleActivity.EventListener" />
        <variable
            name="worker"
            type="com.lsm.databindingtest.Worker"/>
    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:onClick="@{eventlistener.clickFirst}"
            android:text="點(diǎn)擊(方法)" />
        <include
            bind:worker="@{worker}"
            layout="@layout/name" />
    </LinearLayout>
</layout>

name.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="worker"
            type="com.lsm.databindingtest.Worker"/>
    </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:layout_marginTop="10dp"
            android:layout_gravity="center_horizontal"
            android:text="@{worker.firstName}"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:layout_gravity="center_horizontal"
            android:text="@{worker.lastName}"/>
    </LinearLayout>
</layout>

點(diǎn)擊調(diào)用clickFirst方法時(shí)改變inclue 中name.xml中的視圖震捣；

public class SimpleActivity extends AppCompatActivity {
    private ActivitySimpleBinding binding;
    private Worker worker = new Worker("1111", "2222");

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = DataBindingUtil.setContentView(this, R.layout.activity_simple);
        binding.setEventlistener(new EventListener());
        binding.setWorker(worker);
    }
    public class EventListener {
        public void clickFirst(View view) {
            worker.setFirstName("55555");
            worker.setLastName("7777777");
            Toast.makeText(SimpleActivity.this, "點(diǎn)擊了并刷新worker對象的值", Toast.LENGTH_LONG).show();
        }
    }
}

在觸發(fā)點(diǎn)擊事件荔棉，重新對model進(jìn)行賦值后，并沒有做其他動(dòng)作蒿赢，視圖就更新了润樱；

image

include

在BaseObservable視圖更新中其實(shí)就提到了include的使用了；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="worker"
            type="com.lsm.databindingtest.Worker"/>
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <include
            bind:worker="@{worker}"
            layout="@layout/name" />
    </LinearLayout>
</layout>

name.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="worker"
            type="com.lsm.databindingtest.Worker"/>
    </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:layout_marginTop="10dp"
            android:layout_gravity="center_horizontal"
            android:text="@{worker.firstName}"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:layout_gravity="center_horizontal"
            android:text="@{worker.lastName}"/>
    </LinearLayout>
</layout>

activity中的邏輯和上面都差不多羡棵，這里就不說了壹若；

ViewStub

有時(shí)候在項(xiàng)目開發(fā)中會(huì)使用ViewStub進(jìn)行加載視圖，看看在dataBinding中如何使用ViewStub皂冰；

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

    <data>

    </data>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <ViewStub
            android:id="@+id/view_stub"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout="@layout/viewstub"/>
    </LinearLayout>
</layout>

viewstub.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher_round"/>
</LinearLayout>

image

和之前的使用一樣沒有區(qū)別店展；

RecyclerView

在開發(fā)過程中列表(RecyclerView,ListView,GridView等)的使用是比較頻繁的，所有就來看看RecyclerView在dataBinding中是如何綁定數(shù)據(jù)的秃流；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="controllrecyclerview"
            type="com.lsm.databindingtest.RecyclerViewActivity.ControllRecyclerView"/>
    </data>
    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <Button
            android:id="@+id/btn_add"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="增加"
            tools:ignore="MissingConstraints"
            android:onClick="@{controllrecyclerview.addItem}"/>
        <Button
            android:id="@+id/btn_remove"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="刪除"
            tools:ignore="MissingConstraints"
            app:layout_constraintTop_toBottomOf="@+id/btn_add"
            android:onClick="@{controllrecyclerview::removeItem}"/>
        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            tools:ignore="MissingConstraints"
            app:layout_constraintTop_toBottomOf="@+id/btn_remove">
        </android.support.v7.widget.RecyclerView>
    </android.support.constraint.ConstraintLayout>
</layout>

布局中和之前的寫法一樣赂蕴，看看它adapter的寫法有什么不同；

public class BindingViewHolder<T extends ViewDataBinding> extends RecyclerView.ViewHolder {
    private T mBinding;
    public BindingViewHolder(@NonNull T binding) {
        super(binding.getRoot());
        mBinding = binding;
    }
    public T getBinding() {
        return mBinding;
    }
}

這了ViewHolder弄一個(gè)單獨(dú)的類舶胀，沒有將其弄成adapter的內(nèi)部類了概说，實(shí)例化的時(shí)和以前不同的時(shí)傳入dataBinding對象而不是View對象碧注，然后通過getRoot方法去獲取View對象；

public class EmployeeAdapter extends RecyclerView.Adapter<BindingViewHolder> {
    private LayoutInflater mLayoutInflater;
    private OnItemClickListener mListener;
    private List<Worker> mWorkList;

    public interface OnItemClickListener {
        void onItemClickListener(Worker worker);
    }

    public EmployeeAdapter(Context context) {
        this.mLayoutInflater = LayoutInflater.from(context);
        this.mWorkList = new ArrayList<>();
    }

    @NonNull
    @Override
    public BindingViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        ViewDataBinding binding = DataBindingUtil.inflate(mLayoutInflater, R.layout.item_work_on, viewGroup, false);
        return new BindingViewHolder(binding);
    }

    @Override
    public void onBindViewHolder(@NonNull BindingViewHolder bindingViewHolder, int i) {
        final Worker item = mWorkList.get(i);
        ViewDataBinding binding = bindingViewHolder.getBinding();
        binding.setVariable(BR.item, item);
        binding.executePendingBindings();
        bindingViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mListener != null) {
                    mListener.onItemClickListener(item);
                }
            }
        });
    }
    @Override
    public int getItemCount() {
        return mWorkList.size();
    }

    public void setOnItemClickListener(OnItemClickListener listener) {
        this.mListener = listener;
    }

    public void addAll(List<Worker> workers) {
        mWorkList.addAll(workers);
    }

    Random mRandom = new Random(System.currentTimeMillis());

    public void add(Worker worker) {
        int position = mRandom.nextInt(mWorkList.size() +1);
        mWorkList.add(position,worker);
        notifyItemInserted(mWorkList.size());
    }

    public void remove() {
        if (mWorkList.size() == 0) {
            return;
        }
        int position = mRandom.nextInt(mWorkList.size());
        mWorkList.remove(position);
        notifyItemRemoved(position);
    }
}

在onCreateViewHolder方法中通過DataBindingUtil.inflate加載視圖布局糖赔，并創(chuàng)建ViewDataBinding實(shí)例對象萍丐；onBindViewHolder方法中就不用像之前那樣通過獲取控件，然后對控件進(jìn)行賦值放典，直接通過ViewHolder獲取到對應(yīng)的ViewDataBinding碉纺，然后調(diào)用setVariable對視圖進(jìn)行賦值，點(diǎn)擊事件這些也可以按照之前的方式實(shí)現(xiàn)刻撒；
item_work_on.xml

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="item"
            type="com.lsm.databindingtest.Worker"/>
    </data>
    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="50dp">
        <TextView
            android:id="@+id/id_first_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            tools:ignore="MissingConstraints"
            android:text="@{item.firstName}"
            app:layout_constraintBottom_toTopOf="parent"
            app:layout_constraintTop_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            android:layout_marginLeft="10dp"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            tools:ignore="MissingConstraints"
            android:text="@{item.lastName}"
            app:layout_constraintBottom_toTopOf="parent"
            app:layout_constraintTop_toBottomOf="parent"
            app:layout_constraintLeft_toRightOf="@+id/id_first_name"
            android:layout_marginLeft="30dp"/>
    </android.support.constraint.ConstraintLayout>
</layout>

public class RecyclerViewActivity extends AppCompatActivity {
    private ActivityRecyclerviewBinding binding;
    private EmployeeAdapter adapter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = DataBindingUtil.setContentView(this, R.layout.activity_recyclerview);
        binding.recyclerView.setLayoutManager(new LinearLayoutManager(this));

        adapter = new EmployeeAdapter(this);
        binding.recyclerView.setAdapter(adapter);
        adapter.setOnItemClickListener(new EmployeeAdapter.OnItemClickListener() {
            @Override
            public void onItemClickListener(Worker worker) {
                Toast.makeText(RecyclerViewActivity.this, worker.getFirstName() + "--" + worker.getLastName(), Toast.LENGTH_LONG).show();
            }
        });
        binding.setControllrecyclerview(new ControllRecyclerView());
        List<Worker> demoList = new ArrayList<>();
        for (int i = 0; i < 5; i++) {
            Worker worker = new Worker("Zhai", "Mark");
            demoList.add(worker);
        }
        adapter.addAll(demoList);
    }

    public class ControllRecyclerView {
        public void addItem(View view) {
            Worker worker = new Worker("1111", "11111");
            adapter.add(worker);
        }

        public void removeItem(View view) {
            adapter.remove();
        }
    }
}

activity中直接通過dataBinding獲取RecyclerView實(shí)例骨田，然后設(shè)置LayoutMananger和adapter；這樣就實(shí)現(xiàn)了列表數(shù)據(jù)的綁定声怔，對于ListView和GridView列表數(shù)據(jù)的綁定差不多态贤；

image

@BindingAdapter自定義屬性

要將后臺返回的url圖片鏈接通過ImageView顯示在界面上，需要通過第三方圖片加載庫將其加載顯示出來醋火，在dataBinding中xml布局中ImageView并不能通過@{}的方式加載url鏈接悠汽，那怎么來實(shí)現(xiàn)圖片加載呢？通過@BindingAdapter自定義屬性的方式可以實(shí)現(xiàn)芥驳；

public class DemoBindingAdapter {
    @BindingAdapter({"app:imageUrl","app:placeholder"})
    public static void loadImageFromUrl(ImageView view, String url, Drawable drawable){
        Glide.with(view.getContext())
                .load(url)
                .placeholder(drawable)
                .into(view);
    }
}

定義一個(gè)loadImageFromUrl的靜態(tài)方法柿冲，并給方法添加@BindingAdapter注解，在注解中聲明一個(gè)imageUrl和placeholder兆旬，在xml中給imageUrl和placeholder進(jìn)行賦值假抄；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
    <data>
        <variable
            name="employee"
            type="com.lsm.databindingtest.Employee" />
    </data>
    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/iv_a"
            android:layout_width="150dp"
            android:layout_height="150dp"
            app:imageUrl="@{employee.avatar}"
            app:placeholder="@{@drawable/default_avatar}"
            tools:ignore="MissingConstraints" />

        <ImageView
            android:id="@+id/iv_b"
            android:layout_width="150dp"
            android:layout_height="150dp"
            app:imageUrl="@{employee.avatar}"
            app:layout_constraintTop_toBottomOf="@+id/iv_a"
            app:placeholder="@{@drawable/default_avatar}"
            tools:ignore="MissingConstraints" />
    </android.support.constraint.ConstraintLayout>
</layout>

通過app:imageUrl和app:placeholder進(jìn)行引用；

public class ExpressionActivity extends AppCompatActivity {
    private ActivityExpressionBinding binding;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding= DataBindingUtil.setContentView(this,R.layout.activity_expression);
        Employee employee=new Employee("111","3333");
        employee.setAvatar("http://img.tupianzj.com/uploads/allimg/160728/9-160HP91408.jpg");
        binding.setEmployee(employee);
    }
}

image

雙向綁定

雙向綁定的意思就是將數(shù)據(jù)model的值顯示到視圖上面丽猬，model改變時(shí)自動(dòng)更新視圖宿饱，視圖改變時(shí)自動(dòng)更新model；在dataBinding中通過BaseObservable和@={}來實(shí)現(xiàn)脚祟，注意不是@{}(賦值)谬以，是@={}

public class FormModel extends BaseObservable {
    private String userName;
    private String passWord;

    public FormModel() {
    }

    public FormModel(String userName, String passWord) {
        this.userName = userName;
        this.passWord = passWord;
    }
    @Bindable
    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
        notifyPropertyChanged(BR.userName);
    }
    @Bindable
    public String getPassWord() {
        return passWord;
    }

    public void setPassWord(String passWord) {
        this.passWord = passWord;
        notifyPropertyChanged(BR.passWord);
    }
}

數(shù)據(jù)model的寫法還是和BaseObservable視圖自動(dòng)更新寫法一樣的；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <variable
            name="formmodel"
            type="com.lsm.databindingtest.FormModel"/>
        <variable
            name="commitFrom"
            type="com.lsm.databindingtest.TwoWayActivity.CommitFrom"/>
    </data>
    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <EditText
            android:id="@+id/et_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="請輸入用戶名"
            tools:ignore="MissingConstraints"
            android:inputType="textNoSuggestions"
            android:text="@={formmodel.userName}"/>
        <EditText
            android:id="@+id/et_pwd"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="請輸入密碼"
            tools:ignore="MissingConstraints"
            android:inputType="textNoSuggestions"
            android:text="@={formmodel.passWord}"
            app:layout_constraintTop_toBottomOf="@+id/et_name"/>
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="提交"
            tools:ignore="MissingConstraints"
            app:layout_constraintTop_toBottomOf="@+id/et_pwd"
            android:onClick="@{commitFrom.commitFrom}"/>

    </android.support.constraint.ConstraintLayout>
</layout>

public class TwoWayActivity extends AppCompatActivity {
    private ActivityTwoWayBinding binding;
    private FormModel formmodel;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding= DataBindingUtil.setContentView(this,R.layout.activity_two_way);

        formmodel=new FormModel("111","222");
        binding.setFormmodel(formmodel);
        binding.setCommitFrom(new CommitFrom());
        formmodel.addOnPropertyChangedCallback(new Observable.OnPropertyChangedCallback() {
            @Override
            public void onPropertyChanged(Observable sender, int propertyId) {
                //監(jiān)聽發(fā)送改變
            }
        });
    }
    public class CommitFrom{
        public void commitFrom(View view){
            Toast.makeText(TwoWayActivity.this,formmodel.getUserName()+"----"+formmodel.getPassWord(),Toast.LENGTH_LONG).show();
        }
    }
}

在activity中還可以通過addOnPropertyChangedCallback來監(jiān)聽視圖的改變由桌；

image

這樣就實(shí)現(xiàn)了數(shù)據(jù)和視圖的雙向綁定为黎，在點(diǎn)擊提交的時(shí)候并沒有做其他操作，就只是做了一個(gè)Toast提示行您；

動(dòng)畫

接下來看下動(dòng)畫的簡單實(shí)現(xiàn)铭乾；

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <data>
        <import type="android.view.View" />
        <variable
            name="persenter"
            type="com.lsm.databindingtest.AnimationActivity.Persenter" />
        <variable
            name="showImage"
            type="boolean" />
    </data>
    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <ImageView
            android:id="@+id/iv"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@drawable/default_avatar"
            android:visibility="@{showImage?View.VISIBLE:View.GONE}"
            tools:ignore="MissingConstraints" />
        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onCheckedChanged="@{persenter.onCheckedChanged}"
            android:text="圖片顯示或者隱藏"
            tools:ignore="MissingConstraints"
            app:layout_constraintTop_toBottomOf="@+id/iv"/>
    </android.support.constraint.ConstraintLayout>
</layout>

需要注意：不管是不是動(dòng)畫的實(shí)現(xiàn)，如果在布局中通過三元運(yùn)算符等操作運(yùn)算符來控制視圖的顯示或者隱藏邑雅，需要在data節(jié)點(diǎn)標(biāo)簽中做引用片橡；

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

public class AnimationActivity extends AppCompatActivity {
    private ActivityAnimationBinding binding;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding= DataBindingUtil.setContentView(this,R.layout.activity_animation);

        binding.addOnRebindCallback(new OnRebindCallback() {
            @Override
            public boolean onPreBind(ViewDataBinding binding) {
                ViewGroup viewGroup= (ViewGroup) binding.getRoot();
                TransitionManager.beginDelayedTransition(viewGroup);
                return true;
            }
        });
        binding.setPersenter(new Persenter());
    }
    public class Persenter{
        public void onCheckedChanged(View buttonView, boolean isChanged){
            binding.setShowImage(isChanged);
        }
    }
}

image

上面這些只是dataBinding的部分用法妈经，更多的用法可以查閱更多的資料進(jìn)行學(xué)習(xí)淮野。
源碼

來源：Android dataBinding 的綁定數(shù)據(jù)捧书、列表、點(diǎn)擊事件等使用

Android dataBinding 的綁定數(shù)據(jù)、列表故觅、點(diǎn)擊事件等使用

Android dataBinding 的綁定數(shù)據(jù)厂庇、列表、點(diǎn)擊事件等使用

準(zhǔn)備工作：

數(shù)據(jù)綁定

事件綁定

BaseObservable

include

ViewStub

RecyclerView

@BindingAdapter自定義屬性

雙向綁定

動(dòng)畫