android – 双向数据绑定(在xml中),ObservableField,BaseObservable,我应该用哪个进行双向数据绑定？

我已经使用了数据绑定一段时间了,即使现在它也不适用于JDK 8和API 24.我仍然找到一种以更简单的方式使用数据绑定的方法.但是,当我使用以下方式进行精确的双向数据绑定时(在我看来,双向数据绑定就像这里( What is two way binding?),有些奇怪的事情发生了.

1.双向数据绑定(以xml为单位)@H_301_3@

android:text="@={testStr}"

这在官方文档中没有提到(https://developer.android.com/topic/libraries/data-binding/index.html,这个页面通常会更新,现在可能会更改).但它可以将变量绑定到xml.@H_301_3@

2. ObservableField属性@H_301_3@

这里的例子(https://developer.android.com/topic/libraries/data-binding/index.html#observablefields)@H_301_3@

private static class User {
   public final ObservableField<String> firstName =
       new ObservableField<>();
   public final ObservableField<String> lastName =
       new ObservableField<>();
   public final Observableint age = new ObservableInt();
}

3.将模型类扩展为BaSEObservable@H_301_3@

private static class User extends BaSEObservable {
   private String firstName;
   private String lastName;
   @Bindable
   public String getFirstName() {
       return this.firstName;
   }
   @Bindable
   public String getLastName() {
       return this.lastName;
   }
   public void setFirstName(String firstName) {
       this.firstName = firstName;
       notifyPropertyChanged(BR.firstName);
   }
   public void setLastName(String lastName) {
       this.lastName = lastName;
       notifyPropertyChanged(BR.lastName);
   }
}

模型类必须扩展到BaSEObservable类,并且getter方法必须使用“@Bindable”进行注释,并且setter方法需要使用绑定xml中的相应命名调用方法notifyPropertyChange().@H_301_3@

我的问题是,我想知道三种绑定方法的缺点和优点.当然,我知道第一个会更容易.但是我在文档和某些网站上找到了一些时刻.它在下一刻消失了.官方文档未经任何明确公告而更改.我仍然想知道@R_379_10675@用第一种方法,所以我必须准备改变方法2或3.@H_301_3@

student_XML2WAY.java@H_301_3@

public class student_XML2WAY {
    private int age;
    private String name;
    public int getAge() {
        return age;
    }
    public void setAge(int pAgE) {
        age = pAge;
    }
    public String getName() {
        return name;
    }
    public void setName(String pName) {
        name = pName;
    }
}

student_ObserField.java@H_301_3@

public class student_ObserField {
    private Observableint age;
    private ObservableField<String> name;
    public student_ObserField() {
        age = new ObservableInt();
        name = new ObservableField<>();
    }
    public ObservableInt getAge() {
        return age;
    }
    public ObservableField<String> getName() {
        return name;
    }
}

student_Extend.java@H_301_3@

public class student_Extend  extends BaSEObservable{
    private int age;
    private String name;

    @Bindable
    public int getAge() {
        return age;
    }
    public void setAge(int pAgE) {
        age = pAge;
        notifyPropertyChanged(BR.student3);
    }
    @Bindable
    public String getName() {
        return name;
    }
    public void setName(String pName) {
        name = pName;
        notifyPropertyChanged(BR.student3);
    }
}

activity_main.xml中@H_301_3@

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://scheR_585_11845@as.android.com/apk/res/android"
        xmlns:tools="http://scheR_585_11845@as.android.com/tools">

    <data>

        <variable
            name="student1"
            type="example.com.testerapplication.sp.bean.student_XML2WAY"/>

        <variable
            name="student2"
            type="example.com.testerapplication.sp.bean.student_ObserField"/>

        <variable
            name="student3"
            type="example.com.testerapplication.sp.bean.student_Extend"/>

    </data>

    <LinearLayout

        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
      >

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@={student1.name}"/>

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{studenT2.NAME}"/>

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@{student3.namE}"/>
        <Button
            android:id="@+id/btn1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="update"/>
    </LinearLayout>
</layout>

活动类@H_301_3@

public class MainActivity extends AppCompatActivity {
    private student_XML2WAY mstudent1;
    private student_ObserField mstudent2;
    private student_Extend mstudent3;
    @Override
    protected void onCreate(Bundle savedInstanceStatE) {
        super.onCreate(savedInstanceStatE);
        ActivitymainBinding binding = DataBindingUtil.inflate(LayoutInflater.from(this),R.layout.activity_main,null,falsE);
        mstudent1 = new student_XML2WAY();
        mstudent1.setName("XML First");
        mstudent2 = new student_ObserField();
        mstudent2.getName().set("ObserField Second");
        mstudent3 = new student_Extend();
        mstudent3.setName("Extend Third");
        binding.setstudent1(mstudent1);
        binding.setstudent2(mstudent2);
        binding.setstudent3(mstudent3);
        setContentView(binding.getRoot());
        binding.btn1.setOnClickListener(new View.onClickListener() {
            @Override
            public void onClick(View v) {
                mstudent1.setName("student1");
                mstudent2.getName().set("student2");
                mstudent3.setName("student3");
            }
        });
    }
}

student mstudent = new student("John Doe",42); //
binding.setstudent(mstudent);
//later:
mstudent.setAge(37);

public class student {
    private String name;
    private int age;
    //Corresponding setters and getters
}


public class studentviewmodel {
    private ObservableField<student> mstudentField = new ObservableField<>();

    //if I have a large model class,and only want to use some fields,//I create some getters (and setters,for the two way attributes)
    //Something like this:

    public int getAge() {
        return mstudentField.get().getAge();
    }
    public void setAge(int newAgE) {
        return mstudentField.get().setAge(newAgE);
    }
}

<layout>
    <data>
        <variable name="studentviewmodel" 
                  type="locaction.of.studentviewmodel"> <!-- or do an import -->
    </data>
    <EditText 
        android:text="@={studentviewmodel.agE}"/>
</layout>