Android官方DataBinding（五）：ObservableMap，ObservableArrayMap

悠悠 2024-02-18 14:30 13阅读 0赞

**Android官方DataBinding（五）：ObservableMap，ObservableArrayMap**

写一个简单的例子说明ObservableMap，ObservableArrayMap用法。  
建立一个User.java的数据模型：

package zhangphil.test;
    
    import android.databinding.BaseObservable;
    import android.databinding.ObservableArrayMap;
    import android.databinding.ObservableField;
    import android.databinding.ObservableInt;
    import android.databinding.ObservableMap;
    
    /**
     * Created by Phil on 2017/8/17.
     */
    
    public class User extends BaseObservable {
        public final ObservableInt id = new ObservableInt();
        public final ObservableField<String> name = new ObservableField<>();
        public final ObservableMap<String, Object> quality = new ObservableArrayMap<>();
        public final ObservableField<String> current = new ObservableField<>();
    }

Keys.java：

package zhangphil.test;
    
    /**
     * Created by Phil on 2017/8/18.
     */
    
    public class Keys {
        public static final String current = "current_value";
    }

activity\_main.xml布局：

<?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>
            <import type="android.view.View" />
            <import type="zhangphil.test.Keys" />
            <import type="android.databinding.ObservableMap" />
    
            <variable
                name="user"
                type="zhangphil.test.User" />
        </data>
    
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">
    
            <Button
                android:id="@+id/button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="更新" />
    
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@{String.valueOf(user.id)}"
                android:textColor="@android:color/holo_red_light"
                android:visibility="@{ user.id > 0 ? View.VISIBLE : View.GONE }" />
    
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@{user.name}"
                android:textColor="@{user.id == 0 ? @android:color/holo_red_light : @android:color/holo_blue_light}" />
    
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal">
    
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@{user.current}" />
    
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text=" --- " />
    
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@{user.quality[user.current]}" />
            </LinearLayout>
        </LinearLayout>
    </layout>

MainActivity.java：

package zhangphil.test;
    
    import android.databinding.DataBindingUtil;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    
    import zhangphil.test.databinding.ActivityMainBinding;
    
    public class MainActivity extends AppCompatActivity {
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            //setContentView(R.layout.activity_main);
    
            ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
    
            final User user = new User();
            binding.setUser(user);
    
            user.id.set(0);
            user.name.set("zhangphil");
    
            user.quality.put("normal", "N url");
            user.quality.put("high", "H url");
            user.quality.put("super", "S url");
    
            user.current.set("normal");
    
            binding.button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    user.id.set(1);
                    user.quality.put("high", "new H url");
                    user.current.set("high");
                }
            });
        }
    }

代码运行结果，初始化状态：  
![Center][]

点击更新按钮：  
![Center 1][]

附录：  
1，《Android官方DataBinding简例（一）》链接：http://blog.csdn.net/zhangphil/article/details/77322530  
2，《Android官方DataBinding（二）：动态数据更新notifyPropertyChanged》链接：http://blog.csdn.net/zhangphil/article/details/77328688  
3，《Android官方DataBinding（三）：RecyclerView 使用ViewDataBinding更新数据》链接：http://blog.csdn.net/zhangphil/article/details/77367432  
4，《Android官方DataBinding（四）：BindingAdapter》链接：http://blog.csdn.net/zhangphil/article/details/77374211

[Center]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/aeb5337370ab4121bbf95ab90893529d.png
[Center 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/46fbc860816a4fa6a6f644b1d94dc866.png