使用databingding构建一个通用的adapter
第一步构建CommonAdapter
package com.example.commonui.adapter;
import android.text.TextUtils;
import android.util.ArrayMap;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.databinding.DataBindingUtil;
import androidx.databinding.ViewDataBinding;
import androidx.lifecycle.ViewModel;
import androidx.recyclerview.widget.RecyclerView;
import com.example.commonui.BR;
import java.util.ArrayList;
import java.util.List;
public class CommonAdapter extends RecyclerView.Adapter<CommonAdapter.NormalHolder> {
private List<Object> datas;
private ArrayMap<Class,Integer> types;
private ViewModel viewModel;
public CommonAdapter(){
datas = new ArrayList<>();
types = new ArrayMap<>();
}
public void refresh(List<Object> datas){
if(datas!=null){
this.datas.clear();
this.datas.addAll(datas);
notifyDataSetChanged();
}
}
public void register(String type,Integer layout) {
try{
if(!TextUtils.isEmpty(type) && layout!=null && layout>0){
types.put(Class.forName(type),layout);
}
}catch (Exception ex){
ex.printStackTrace();
}
}
@NonNull
@Override
public NormalHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View viewRoot = View.inflate(parent.getContext(),viewType, null);
ViewDataBinding binding = DataBindingUtil.bind(viewRoot);
return new NormalHolder(binding);
}
@Override
public void onBindViewHolder(@NonNull NormalHolder holder, int position) {
holder.dataBinding.setVariable(BR.item,datas.get(position));
holder.dataBinding.setVariable(BR.model,viewModel);
holder.dataBinding.executePendingBindings();
}
@Override
public int getItemCount() {
return datas.size();
}
@Override
public int getItemViewType(int position) {
Object item = datas.get(position);
if(types.containsKey(item.getClass())){
return types.get(item.getClass());
}
return super.getItemViewType(position);
}
public void setViewModel(ViewModel viewModel) {
this.viewModel = viewModel;
}
public class NormalHolder extends RecyclerView.ViewHolder {
ViewDataBinding dataBinding;
public NormalHolder(ViewDataBinding dataBinding) {
super(dataBinding.getRoot());
this.dataBinding = dataBinding;
}
}
}
第二部创建CommonBindingAdapter
package com.example.commonui.bindingAdapter;
import androidx.databinding.BindingAdapter;
import androidx.lifecycle.ViewModel;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.example.commonui.adapter.CommonAdapter;
import java.util.List;
public class CommonBindingAdapter {
@BindingAdapter(value = {"model","datas","item1","type1"},requireAll = false)
public static void initRecyclerview(RecyclerView recyclerView, ViewModel vm, List datas, Integer item1, String type1){
RecyclerView.Adapter recyclerViewAdapter = recyclerView.getAdapter();
CommonAdapter adapter = null;
if(recyclerViewAdapter == null){
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(recyclerView.getContext());
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(linearLayoutManager);
adapter = new CommonAdapter();
adapter.setViewModel(vm);
adapter.register(type1,item1);
adapter.refresh(datas);
recyclerView.setAdapter(adapter);
}else if(datas!=null){
adapter = (CommonAdapter)recyclerViewAdapter;
adapter.refresh(datas);
}
}
}
如果要使用多个item和多个type可以多写几个参数，如果要处理表格布局也可以加参数来自定义
第三步集成
activity代码如下
package com.example.myapplication;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import androidx.lifecycle.ViewModelProvider;
import com.example.myapplication.databinding.ActivityMainBindingImpl;
import com.example.myapplication.vm.MainViewModel;
import dagger.hilt.android.AndroidEntryPoint;
@AndroidEntryPoint
public class MainActivity extends AppCompatActivity {
MainViewModel viewModel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityMainBindingImpl binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.setLifecycleOwner(this);
viewModel = new ViewModelProvider(this).get(MainViewModel.class);
binding.setModel(viewModel);
}
}
viewModel代码如下
package com.example.myapplication.vm;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;
import com.example.usercenter.UserService;
import java.util.List;
import javax.inject.Inject;
import dagger.hilt.android.lifecycle.HiltViewModel;
@HiltViewModel
public class MainViewModel extends ViewModel {
public MutableLiveData<List<String>> datas = new MutableLiveData<>();
UserService userService;
@Inject
public MainViewModel(UserService userService){
this.userService = userService;
init();
}
public void init(){
userService.load();
datas.setValue(userService.getNames());
}
public void speak(String name){
userService.setAge(name,24);
datas.setValue(userService.getNames());
}
}
UserService代码如下
package com.example.usercenter;
import java.util.ArrayList;
import java.util.List;
import javax.inject.Inject;
public class UserService {
private List<String> names;
@Inject
public UserService(){
names = new ArrayList<>();
}
public void load(){
names.add("吴中区");
names.add("李世民");
names.add("李元把");
}
public List<String> getNames() {
return names;
}
public void setAge(String name,int age){
int i= names.indexOf(name);
if(i >=0){
names.set(i,name+" "+age);
}
}
}
activity_main代码如下
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="model"
type="com.example.myapplication.vm.MainViewModel" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:model="@{model}"
app:datas="@{model.datas}"
app:item1="@{ @layout/item }"
app:type1="@{ `java.lang.String`}"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
说明：xml中绑定属性即可
item.xml代码如下
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:ignore="MissingDefaultResource">
<data>
<variable
name="model"
type="com.example.myapplication.vm.MainViewModel" />
<variable
name="item"
type="java.lang.String" />
</data>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clickable="true"
android:onClick="@{()->model.speak(item)}"
android:padding="10dp"
android:text="@{item}"
android:textColor="@color/black"
android:textSize="32sp"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
结尾：其中使用hilt可以参照官网自行集成
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