2019-04-11Android泛型化使用

示例代码如下:

package com.example.dell.basebindingadaptertest.act;

import android.arch.lifecycle.ViewModel;
import android.arch.lifecycle.ViewModelProvider;
import android.arch.lifecycle.ViewModelStore;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.databinding.DataBindingUtil;
import android.databinding.ViewDataBinding;
import android.os.Bundle;
import android.support.annotation.CallSuper;
import android.support.annotation.CheckResult;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;

import com.example.dell.basebindingadaptertest.constant.Constant;
import com.example.dell.basebindingadaptertest.utils.ClassUtil;
import com.example.dell.basebindingadaptertest.utils.StatusBarUtil;
import com.trello.rxlifecycle2.LifecycleProvider;
import com.trello.rxlifecycle2.LifecycleTransformer;
import com.trello.rxlifecycle2.RxLifecycle;
import com.trello.rxlifecycle2.android.ActivityEvent;
import com.trello.rxlifecycle2.android.RxLifecycleAndroid;

import io.reactivex.Observable;
import io.reactivex.subjects.BehaviorSubject;

/**
 * Created by chentao
 * Date:2019/3/19
 * Description:如果这里继承的是RxActivity 因为RxActivity的父类是Activity它没有提供getSuppportFragmentManager方法
 *  所以这里要继承自FragmentActivity或者AppCompatActivity
 */
public abstract class JavaMvvmActivity<VM extends ViewModel,T extends ViewDataBinding> extends AppCompatActivity implements LifecycleProvider<ActivityEvent> {

    protected final String TAG="gdchent";
    protected T binding=null ;
    protected ViewModel VM;
    protected abstract int getLayloutId() ;
    protected Context context;
    protected abstract  void init();
    protected SharedPreferences sp=null;
    //实现生命周期控制
    private final BehaviorSubject<ActivityEvent> lifecycleSubject = BehaviorSubject.create();

    @NonNull
    @CheckResult
    public final Observable<ActivityEvent> lifecycle() {
        return lifecycleSubject.hide();
    }



    @Override
    @NonNull
    @CheckResult
    public <T> LifecycleTransformer<T> bindUntilEvent(ActivityEvent event) {
        return RxLifecycle.bindUntilEvent(lifecycleSubject, event);
    }

    @NonNull
    @CheckResult
    @Override
    public <T> LifecycleTransformer<T> bindToLifecycle() {
        return RxLifecycleAndroid.bindActivity(lifecycleSubject);
    }

    @Override
    @CallSuper
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding=DataBindingUtil.setContentView(this,getLayloutId());
        context=this;
        sp=getSharedPreferences(Constant.SP_NAME, Context.MODE_PRIVATE);
        initViewModel();
        init();
        setOnlickListener();
        lifecycleSubject.onNext(ActivityEvent.CREATE);
        //ContextCompat.getColor(this,android.R.color.holo_red_dark
        StatusBarUtil.setTranslucentForImageView(this,binding.getRoot() );
    }
   //在基类 通过泛型初始化ViewModel利用反射
    protected void initViewModel(){
        Class<ViewModel> viewModelClass=ClassUtil.getViewModel(this);
        if(viewModelClass!=null) {
            ViewModelStore viewModelStore=new ViewModelStore();
            //通过viewModelProvider
            ViewModelProvider viewModelProvider = new ViewModelProvider(viewModelStore,new ViewModelProvider.AndroidViewModelFactory(getApplication()));
            VM=viewModelProvider.get(viewModelClass);
        }
    }

    protected void setOnlickListener(){}

    //打开Activity
    protected void startActivity(Context context,Class clazz){
        Intent intent=new Intent(context,clazz);
        startActivity(intent);
    }
    protected void startActivityAndBundle(Context context,Class clazz,Bundle bundle){
        Intent intent=new Intent(context,clazz);
        intent.putExtra(Constant.BUNDLE_NAME,bundle);
        startActivity(intent);
    }


    @Override
    @CallSuper
    protected void onStart() {
        super.onStart();
        lifecycleSubject.onNext(ActivityEvent.START);
    }

    @Override
    @CallSuper
    protected void onResume() {
        super.onResume();
        lifecycleSubject.onNext(ActivityEvent.RESUME);
    }

    @Override
    @CallSuper
    protected void onPause() {
        lifecycleSubject.onNext(ActivityEvent.PAUSE);
        super.onPause();
    }

    @Override
    @CallSuper
    protected void onStop() {
        lifecycleSubject.onNext(ActivityEvent.STOP);
        super.onStop();
    }

    @Override
    @CallSuper
    protected void onDestroy() {
        lifecycleSubject.onNext(ActivityEvent.DESTROY);
        super.onDestroy();
    }

}

泛型化工具代码：

public class ClassUtil {

    /**
     * 获取泛型ViewModel的class对象
     */
    public static <T> Class<T> getViewModel(Object obj) {
        Class<?> currentClass = obj.getClass();
        Class<T> tClass = getGenericClass(currentClass, AndroidViewModel.class);
        if (tClass == null || tClass == AndroidViewModel.class || tClass == NoViewModel.class) {
            return null;
        }
        return tClass;
    }

    private static <T> Class<T> getGenericClass(Class<?> klass, Class<?> filterClass) {
        Type type = klass.getGenericSuperclass();
        if (type == null || !(type instanceof ParameterizedType)) return null;
        ParameterizedType parameterizedType = (ParameterizedType) type;
        Type[] types = parameterizedType.getActualTypeArguments();
        for (Type t : types) {
            Class<T> tClass = (Class<T>) t;
            if (filterClass.isAssignableFrom(tClass)) {
                return tClass;
            }
        }
        return null;
    }
}

例如子类Act代码如下：

/**
 * 主页面一个Framelayout
 * 实现逻辑
 */
public class JavaMainActivity extends JavaMvvmActivity<JavaMainViewModel,ActivityJavaMainBinding> {

    @Override
    protected int getLayloutId() {
        return R.layout.activity_java_main;
    }

    @Override
    protected void init() {
        
        //binding.setVm(VM);
        binding.setVariable(BR.vm,VM);
        //Framelyaout 添加子的Fragment 动态添加
        /**
         * 实现思路是 通过FragmentManager来动态添加
         */
        //第一步 获取FragmentManager
        FragmentManager fm =getSupportFragmentManager();

        ViewPagerFragment viewPagerFragment = new ViewPagerFragment();
        FragmentTransaction ft = fm.beginTransaction();
        ft.add(R.id.container, viewPagerFragment, ViewPagerFragment.VP_FRAGMENT_TAG);
        ft.commit();
    }
}

通过xml绑定ViewModel示例代码如下:

<?xml version="1.0" encoding="utf-8"?>

<layout xmlns:android="http://schemas.android.com/apk/res/android">

     <data>
            <variable
                name="vm"
                type="com.example.dell.basebindingadaptertest.viewmodel.JavaMainViewModel"  />
     </data>
   <FrameLayout
       android:id="@+id/container"
       android:layout_width="match_parent"
       android:layout_height="match_parent">

   </FrameLayout>
</layout>

总结：每个Act或者Frag绑定一个viewModel ，一般Viewmodel是跟xml进行绑定，所以初始化viewModel在获取viewDatabinding之后
详细代码参见github传送门:
https://github.com/gdchent/BaseBindingAdapter