Android DataBinding的使用

DataBinding函数库的引入方式：

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

DataBinding的布局文件

• 以layout为根布局标签，包含data和view两个标签
• data标签用来实现数据绑定
• view标签就是布局

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <variable
            name="bookitem"
            type="com.example.firstpro.model.BookItem" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:text="@{bookitem.mName}" />
        <TextView
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:layout_marginTop="20dp"
            android:text="@{bookitem.mTitle}" />
    </LinearLayout>
</layout>

注：
bookitem：属性变量，类型为BookItem的Java类
@{bookitem.mName}：将控件的值和bookitem的成员变量联系在一起

数据对象

/**
 * @author Administrator
 */
public class BookItem implements Parcelable {
    public final  String mName;
    public final String mLastTime;
    public final String mTitle;
    public final String mPath;

    public BookItem(String mName, String mLastTime, String mTitle, String mPath) {
        this.mName = mName;
        this.mLastTime = mLastTime;
        this.mTitle = mTitle;
        this.mPath = mPath;
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(this.mName);
        dest.writeString(this.mLastTime);
        dest.writeString(this.mTitle);
        dest.writeString(this.mPath);
    }
    protected BookItem(Parcel in) {
        this.mName = in.readString();
        this.mLastTime = in.readString();
        this.mTitle = in.readString();
        this.mPath = in.readString();
    }

    public static final Parcelable.Creator<BookItem> CREATOR = new Parcelable.Creator<BookItem>() {
        @Override
        public BookItem createFromParcel(Parcel source) {
            return new BookItem(source);
        }

        @Override
        public BookItem[] newArray(int size) {
            return new BookItem[size];
        }
    };
}

数据绑定

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        MainActivityBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity);

        BookItem book = new BookItem("你好", "2018-7-24", "Test", "../../../img");
        binding.setBookitem(book);
    }

事件绑定

xml中的绑定代码：

  <data>
        <variable
            name="bookitem"
            type="com.example.firstpro.model.BookItem" />
        <variable
            name="click"
            type="com.example.firstpro.MainActivity" />
    </data>

事件处理类：

    public void onClickName(View view) {
        Toast.makeText(view.getContext(), book.mName, Toast.LENGTH_SHORT).show();
    }

    public void onClickTitle(View view) {
        Toast.makeText(view.getContext(), book.mTitle, Toast.LENGTH_SHORT).show();
    }

注意
需要添加

binding.setClick(this);

完整的Activity:

public class MainActivity extends AppCompatActivity {

    BookItem book = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        MainActivityBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity);

        book = new BookItem("你好", "2018-7-24", "Test", "../../../img");
        binding.setBookitem(book);
        binding.setClick(this);
    }


    public void onClickName(View view) {
        Toast.makeText(view.getContext(), book.mName, Toast.LENGTH_SHORT).show();
    }

    public void onClickTitle(View view) {
        Toast.makeText(view.getContext(), book.mTitle, Toast.LENGTH_SHORT).show();
    }
}

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