databinding简单使用(java+kotlin)

databinding 基本使用，点击事件，自定义属性，recyclerview使用页面是一个RecyclerView，Item为图片 + 姓名 + 年龄配置android {...dataBinding {enabled true}}dependencies {...implementation 'com.github.bumptec...

tj297202234

497人浏览 · 2019-10-12 14:48:44

tj297202234 · 2019-10-12 14:48:44 发布

databinding 基本使用，点击事件，自定义属性，recyclerview使用

页面是一个RecyclerView，Item为图片 + 姓名 + 年龄
在这里插入图片描述
配置

android {
	...
	dataBinding {
        enabled true
    }
}
dependencies {
	...
    implementation 'com.github.bumptech.glide:glide:4.10.0'
    implementation 'com.android.support:recyclerview-v7:29.0.2'
    }

java版本

xml布局文件，主页面
activity_main_java

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

    <data>
        <variable
            name="person"
            type="com.tongjin.mvvm_kotlin.java.PersonsViewModel" />
    </data>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</layout>

item布局，item_java

<?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="person"
            type="com.tongjin.mvvm_kotlin.java.PersonViewModel" />
    </data>

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

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:onClick="@{person.itemClick}"
            android:padding="10dp">

            <ImageView
                android:layout_width="90dp"
                android:layout_height="120dp"
                android:scaleType="centerCrop"
                app:image="@{person.photo}"/>

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

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="10dp"
                    android:text="@{person.name}"
                    android:textSize="18sp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="10dp"
                    android:layout_marginLeft="10dp"
                    android:textSize="18sp"
                    android:text="@{String.valueOf(person.age)}"/>

            </LinearLayout>
        </LinearLayout>

    </LinearLayout>

</layout>

MainActivityJava

public class MainActivityJava extends AppCompatActivity {

    private Handler handler = new Handler();
    private PersonsViewModel persons;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityMainJavaBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main_java);
        persons = new PersonsViewModel();
        binding.setPerson(persons);

        CommonRecyclerViewAdapter<PersonViewModel, ItemJavaBinding> adapter = new CommonRecyclerViewAdapter<>(this, R.layout.item_java, BR.person, persons.personsList);
        binding.list.setLayoutManager(new LinearLayoutManager(this));
        binding.list.setAdapter(adapter);

        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                persons.personsList.add(new PersonViewModel("https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1570799520739&di=57dabff1116da2ce2e860f751063495f&imgtype=0&src=http%3A%2F%2Fi0.hdslb.com%2Fbfs%2Falbum%2Ffee6ff8f524a42eabb75f1538d7312cfdd246b9e.jpg", "王五", 100));
            }
        }, 3000);

    }
}

PersonsViewModel

public class PersonsViewModel {

    public ObservableList<PersonViewModel> personsList = new ObservableArrayList<>();

    public PersonsViewModel() {
        personsList.add(new PersonViewModel("", "aa", 33));
    }
}

PersonViewModel

public class PersonViewModel {

    public ObservableField<String> photo = new ObservableField<>();
    public ObservableField<String> name = new ObservableField<>();
    public ObservableInt age = new ObservableInt();

    public PersonViewModel(String photo, String name, int age) {
        this.photo.set(photo);
        this.name.set(name);
        this.age.set(age);
    }

    // 可以加上命名空间：app:image，但xml中只可以用app:image
    @BindingAdapter("image")
    public static void bindImage(ImageView imageView, String photo) {
        Glide.with(imageView.getContext()).load(photo).into(imageView);
    }

    public void itemClick(View view) {
        Toast.makeText(view.getContext(), name.get(), Toast.LENGTH_SHORT).show();
    }
}

通用的Adapter

public class CommonRecyclerViewAdapter<M, B extends ViewDataBinding> extends RecyclerView.Adapter {
    private Context context;
    private ObservableList<M> items;
    private int layoutId;
    private int resId;
    protected ListChangedCallback itemsChangeCallback;

    public CommonRecyclerViewAdapter(Context context, int layoutId, int resId, ObservableList<M> list) {
        this.context = context;
        this.layoutId = layoutId;
        this.resId = resId;
        this.items = list;
        this.itemsChangeCallback = new ListChangedCallback();
    }

    public ObservableList<M> getItems() {
        return items;
    }

    public class BaseBindingViewHolder extends RecyclerView.ViewHolder {
        public BaseBindingViewHolder(View itemView) {
            super(itemView);
        }
    }

    @Override
    public int getItemCount() {
        return this.items.size();
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        B binding = DataBindingUtil.inflate(LayoutInflater.from(this.context), layoutId, parent, false);
        return new BaseBindingViewHolder(binding.getRoot());
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        B binding = DataBindingUtil.getBinding(holder.itemView);
        if (binding != null) {
            binding.setVariable(resId, this.items.get(position));
        }
    }

    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
        this.items.addOnListChangedCallback(itemsChangeCallback);
    }

    @Override
    public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
        super.onDetachedFromRecyclerView(recyclerView);
        this.items.removeOnListChangedCallback(itemsChangeCallback);
    }

    //region 处理数据集变化
    protected void onChanged(ObservableArrayList<M> newItems) {
        resetItems(newItems);
        notifyDataSetChanged();
    }

    protected void onItemRangeChanged(ObservableArrayList<M> newItems, int positionStart, int itemCount) {
        resetItems(newItems);
        notifyItemRangeChanged(positionStart, itemCount);
    }

    protected void onItemRangeInserted(ObservableArrayList<M> newItems, int positionStart, int itemCount) {
        resetItems(newItems);
        notifyItemRangeInserted(positionStart, itemCount);
    }

    protected void onItemRangeMoved(ObservableArrayList<M> newItems) {
        resetItems(newItems);
        notifyDataSetChanged();
    }

    protected void onItemRangeRemoved(ObservableArrayList<M> newItems, int positionStart, int itemCount) {
        resetItems(newItems);
        notifyItemRangeRemoved(positionStart, itemCount);
    }

    protected void resetItems(ObservableArrayList<M> newItems) {
        this.items = newItems;
    }

    private class ListChangedCallback extends ObservableArrayList.OnListChangedCallback<ObservableArrayList<M>> {
        @Override
        public void onChanged(ObservableArrayList<M> newItems) {
            CommonRecyclerViewAdapter.this.onChanged(newItems);
        }

        @Override
        public void onItemRangeChanged(ObservableArrayList<M> newItems, int i, int i1) {
            CommonRecyclerViewAdapter.this.onItemRangeChanged(newItems, i, i1);
        }

        @Override
        public void onItemRangeInserted(ObservableArrayList<M> newItems, int i, int i1) {
            CommonRecyclerViewAdapter.this.onItemRangeInserted(newItems, i, i1);
        }

        @Override
        public void onItemRangeMoved(ObservableArrayList<M> newItems, int i, int i1, int i2) {
            CommonRecyclerViewAdapter.this.onItemRangeMoved(newItems);
        }

        @Override
        public void onItemRangeRemoved(ObservableArrayList<M> sender, int positionStart, int itemCount) {
            CommonRecyclerViewAdapter.this.onItemRangeRemoved(sender, positionStart, itemCount);
        }
    }
}

kotlin

增加配置

apply plugin: 'kotlin-kapt'

kapt {
    generateStubs = true
}

xml布局，与java的一样
activity_main_kotlin

<?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="persons"
            type="com.tongjin.mvvm_kotlin.kotlin.PersonsViewModel" />
    </data>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</layout>

item_kotlin

<?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="person_kotlin"
            type="com.tongjin.mvvm_kotlin.kotlin.PersonViewModel" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="@{person_kotlin.itemClick}"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="10dp">

            <ImageView
                android:layout_width="90dp"
                android:layout_height="120dp"
                android:scaleType="centerCrop"
                app:image="@{person_kotlin.photo}"/>

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

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="10dp"
                    android:text="@{person_kotlin.name}"
                    android:textSize="18sp"/>

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="10dp"
                    android:layout_marginLeft="10dp"
                    android:textSize="18sp"
                    android:text="@{String.valueOf(person_kotlin.age)}"/>

            </LinearLayout>
        </LinearLayout>
    </LinearLayout>
</layout>

MainActivityKotlin

class MainActivityKotlin : AppCompatActivity() {

    private val handler = Handler()
    private lateinit var persons: PersonsViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val binding = DataBindingUtil.setContentView<ActivityMainKotlinBinding>(this, R.layout.activity_main_kotlin)
        persons = PersonsViewModel()
        binding.persons = persons

        val adapter = CommonRecyclerViewAdapter<PersonViewModel, ItemKotlinBinding>(this@MainActivityKotlin, R.layout.item_kotlin, BR.person_kotlin, persons.persons)
        binding.list.layoutManager = LinearLayoutManager(this)
        binding.list.adapter = adapter

        handler.postDelayed({
            persons.persons.add(PersonViewModel(
                    "https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1570799520739&di=57dabff1116da2ce2e860f751063495f&imgtype=0&src=http%3A%2F%2Fi0.hdslb.com%2Fbfs%2Falbum%2Ffee6ff8f524a42eabb75f1538d7312cfdd246b9e.jpg",
                    "赵六",
                    300
                )
            )
        }, 3000)
    }
}

PersonsViewModel

 class PersonsViewModel {

    val persons = ObservableArrayList<PersonViewModel>()

    init {
        persons.add(PersonViewModel("", "tt", 50))
    }
}

PersonViewModel

class PersonViewModel (photo: String,
                       name: String,
                       age: Int) {

    val photo = ObservableField<String>()
    val name = ObservableField<String>()
    val age = ObservableInt()

    init {
        this.photo.set(photo)
        this.name.set(name)
        this.age.set(age)
    }

    companion object {
        @BindingAdapter("image")
        @JvmStatic
        fun bindImage(imageView: ImageView, photo: String) {
            Glide.with(imageView.context).load(photo).into(imageView)
        }
    }

    fun itemClick(view: View) {
        Toast.makeText(view.context, name.get(), Toast.LENGTH_SHORT).show()
    }
}