[移动开发]Android DataBinding

Android30

配置DataBinding

1）创建一个空项目

2）修改app/build.gradle文件

增加如下内容：

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

3）修改xml文件

格式如下：

<?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"
    xmlns:tools="http://schemas.android.com/tools">

    <data>

    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="hello" />

    </LinearLayout>
</layout>

示例1 - 替换findViewById

activity_main.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"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical"
        >
        <Button
            android:id="@+id/change_bt"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="click"
            />
        <TextView
            android:id="@+id/text_tv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text="hello"
            />
    </LinearLayout>
</layout>

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.os.Bundle;
import android.view.View;
import com.example.mydatabindingtest.databinding.ActivityMainBinding;
import java.util.Random;

public class MainActivity extends AppCompatActivity {
    private ActivityMainBinding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        binding = DataBindingUtil.setContentView(this, R.layout.activity_main);

        binding.changeBt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                binding.textTv.setText("hello" + new Random().nextInt(100));
            }
        });

//        findViewById(R.id.change_bt).setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View v) {
//                binding.textTv.setText("world" + new Random().nextInt(100));
//            }
//        });
    }
}

效果

示例2 - UI绑定 、xml中字符串拼接

创建Student.java

public class Student {
    private String name;
    private int age;
    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

activity_main.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"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <variable
            name="student"
            type="com.example.mydatabindingtest.Student" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical"
        >

        <Button
            android:id="@+id/change_bt"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="change"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text="@{`name为：` + student.name}"
            />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text='@{student.age+""}'
            />
    </LinearLayout>
</layout>

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.os.Bundle;
import android.view.View;
import com.example.mydatabindingtest.databinding.ActivityMainBinding;
import java.util.Random;

public class MainActivity extends AppCompatActivity {
    private ActivityMainBinding binding;
    private Student student;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        student = new Student("zs", 21);
        binding.setStudent(student);

        binding.changeBt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 修改
                student.setAge(new Random().nextInt(200));

                // 方式1
//                binding.setStudent(student);
                // 方式2
                binding.setVariable(BR.student, student);

            }
        });
    }
}

效果

示例3 - UI绑定 - 注解

创建Student.java

import androidx.databinding.BaseObservable;
import androidx.databinding.Bindable;

public class Student extends BaseObservable {
    private String name;
    private int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }
    
    @Bindable
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
        notifyPropertyChanged(BR.name);
    }

    @Bindable
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
        notifyPropertyChanged(BR.age);
    }
}

activity_main.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"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <variable
            name="student"
            type="com.example.mydatabindingtest.Student" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical"
        >

        <Button
            android:id="@+id/change_bt"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="change"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text="@{`name为：` + student.name}"
            />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text='@{student.age+""}'
            />
    </LinearLayout>
</layout>

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.os.Bundle;
import android.view.View;
import com.example.mydatabindingtest.databinding.ActivityMainBinding;
import java.util.Random;

public class MainActivity extends AppCompatActivity {
    private ActivityMainBinding binding;
    private Student student;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        student = new Student("zs", 21);
        binding.setStudent(student);

        binding.changeBt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                student.setAge(new Random().nextInt(200));
                student.setName("lisi" + new Random().nextInt(10));
            }
        });
    }
}

效果

示例4 - 事件绑定

创建Student.java

import androidx.databinding.BaseObservable;
import androidx.databinding.Bindable;

public class Student extends BaseObservable {
    private String name;
    private int age;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Bindable
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
        notifyPropertyChanged(BR.name);
    }

    @Bindable
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
        notifyPropertyChanged(BR.age);
    }
}

MyListener.java

import android.util.Log;
import android.view.View;

public class MyListener {
    private static final String TAG = "AAAAAAAAA";

    // 普通方法绑定
    public void onTextChanged(CharSequence s, int start, int before, int color) {
        Log.d(TAG, "onTextChanged: " + s.toString());
    }

    // 普通方法绑定
    public void onClick(View view) {
        Log.d(TAG, "onClick: ");
    }

    // 监听器绑定，可以返回数据
    public void onClickBinding(Student student) {
        Log.d(TAG, "onClickBinding: name: " + student.getName()
                + ", age:" + student.getAge());
    }
}

activity_main.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"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <variable
            name="student"
            type="com.example.mydatabindingtest.Student" />
        <variable
            name="mylistener"
            type="com.example.mydatabindingtest.MyListener" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical"
        >

        <Button
            android:id="@+id/change_bt"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="change"
            />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text="@{`name为：` + student.name}"
            android:onClick="@{mylistener::onClick}"
            />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="30sp"
            android:text='@{student.age+""}'
            android:onClick="@{()->mylistener.onClickBinding(student)}"
            />

        <EditText
            android:layout_width="300dp"
            android:layout_height="wrap_content"
            android:hint="请输入："
            android:onTextChanged="@{mylistener::onTextChanged}"
            />
    </LinearLayout>
</layout>

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.os.Bundle;
import android.view.View;
import com.example.mydatabindingtest.databinding.ActivityMainBinding;
import java.util.Random;

public class MainActivity extends AppCompatActivity {
    private ActivityMainBinding binding;
    private Student student;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        student = new Student("zs", 21);
        binding.setStudent(student);
        binding.setMylistener(new MyListener());

        binding.changeBt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                student.setAge(new Random().nextInt(200));
                student.setName("lisi" + new Random().nextInt(10));
            }
        });
    }
}

效果

方法

DataBindingUtil.setContentView

将 Activity 的内容视图设置为给定的布局并返回关联的绑定。 给定的布局资源不能是合并布局。

ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);

getRoot()

返回与 Binding 关联的布局文件中最外层的 View。 如果此绑定用于合并布局文件，则将返回合并标记中的第一个根。

binding.getRoot()