架构师成长之路-基于android fragment通信的面向对象的万能接口 _成长之路

青春须早为，岂能长少年。这篇文章主要讲述架构师成长之路-基于android fragment通信的面向对象的万能接口相关的知识，希望能为你提供帮助。
前言
开发一个app时，常用Activity和Fragment，由于操作方便Fragment越来越受欢迎，这样就避免不了Activity和Fragment、Fragment和Fragment之间的通信，我们知道Fragment和Fragment之间不能直接进行通信的，而是通过Activity进行通信。那么Activity和Fragment有几种通信方式呢，它们的优缺点又是什么？一常用的Activity和Fragment几种通信方式 1 通过Handle 在Activity创建一个Handle机制实例，然后在创建Fragment的通过构造方法把Handle实例传递过去，这样Fragment就可以往Activity传送数据了。但这样如下缺点：（1）Activity和Fragment之间耦合性增大；（2）Activity处理后的结果不能实时反馈给Fragment；（3）提高了内存泄漏风险； 2 使用static变量缺点很明确增大内存消耗； 3 使用广播分别在Activity和Fragment中注册广播，这样就可以实现通信了。其缺点：（1）性能差，有延迟，用户体验就会差；（2）一般使用的是标准广播，一个发送，多个接收者，大材小用，性能差；（3）代码冗余；（4）传播的数据有限； 4 EventBus 、rxBus（俗称万能油）其使用方法参考官方文档，其优点就是实用起来简单方便，其缺点也很明显：（1）EventBus 、rxBus其内部使用的是反射机制，那么其性能就会降低；（2）代码维护困难（不熟悉的项目代码的新人很难找到实现的方法在是如何调用的）；（3）数据返回困难，它们是单向传递； 5 普通接口在Fragment写一个接口，让Activity去实现这个接口，通过这个接口把Activity与Fragment绑定在一起，这样Activity和Fragment实时进行通信了，其实谷歌推荐就是这么干的，由于每个Fragment都写一个接口，就会造成代码冗余；如果Fragment少的话还好，多的话，Activity实现多个接口，显得Activity头部很大，况且接口的命名也是一个问题；二万能接口如果在5的基础能够解决代码冗余、接口命名就好了，我们知道一个函数包括函数名、函数体、参数、返回值，那么就可以通过搭建一个简单的框架实现上述问题。 1 建立基类

public abstractclass Function { /** 方法名 */ public String mFunctionName ; public Function (String funName){ this.mFunctionName = funName; }}

【架构师成长之路-基于android fragment通信的面向对象的万能接口】2 建立无（有）参数无（有）四类

/** *无参无返回值 * < h3> Description< /h3> * TODO * < h3> Author< /h3> luzhenbang * < h3> Date< /h3> 2018/1/4 16:13 * < h3> Copyright< /h3> Copyright (c)2018 Shenzhen TLCo., Ltd. Inc. All rights reserved. */ public abstract class FunctionNoParamNoResult extends Function {public FunctionNoParamNoResult(String funName) { super(funName); }public abstract void function(); }

/** *有参无返回值 * < h3> Description< /h3> * TODO * < h3> Author< /h3> luzhenbang * < h3> Date< /h3> 2018/1/4 16:13 * < h3> Copyright< /h3> Copyright (c)2018 Shenzhen TLCo., Ltd. Inc. All rights reserved. */public abstract class FunctionWithParamOnly< Param> extends Function { public FunctionWithParamOnly(String funName) { super(funName); } public abstract void function(Param param); }

/** *有参有返回值 * < h3> Description< /h3> * TODO * < h3> Author< /h3> luzhenbang * < h3> Date< /h3> 2018/1/4 16:13 * < h3> Copyright< /h3> Copyright (c)2018 Shenzhen TLCo., Ltd. Inc. All rights reserved. */public abstract class FunctionWithParamWithResult< Result,Param> extends Function { public FunctionWithParamWithResult(String funName) { super(funName); } public abstract Result function(Param param); }

/** *无参有返回值 * < h3> Description< /h3> * TODO * < h3> Author< /h3> luzhenbang * < h3> Date< /h3> 2018/1/4 16:13 * < h3> Copyright< /h3> Copyright (c)2018 Shenzhen TLCo., Ltd. Inc. All rights reserved. */public abstract class FunctionWithResultOnly< Result> extends Function { public FunctionWithResultOnly(String funName) { super(funName); } public abstract Result function(); }

3 建立管理器类

public class FunctionManager {private static FunctionManager instance = null; public static final String TAG = FunctionManager.class.getSimpleName() + "--------> "; /**容器，用来存储方法名字 key 对应的方法名 value 对应的是参数返回对象*/ private HashMap< String,FunctionWithParamWithResult> mFunctionWithParamWithResultHashMap = null; private HashMap< String,FunctionWithParamOnly> mFunctionWithParamsOnlyHashMap = null; private HashMap< String,FunctionWithResultOnly> mFunctionWithResultOnlyHashMap = null; private HashMap< String,FunctionNoParamNoResult> mFunctionNoParamNoResultHashMap = null; private FunctionManager() { mFunctionNoParamNoResultHashMap = new HashMap< > (); mFunctionWithParamWithResultHashMap = new HashMap< > (); mFunctionWithParamsOnlyHashMap = new HashMap< > (); mFunctionWithResultOnlyHashMap = new HashMap< > (); }public static FunctionManager getInstance() { if (null == instance){ instance = new FunctionManager(); } return instance; }/** * 添加无参无返回值的方法 * @return */ public FunctionManager addFunction(FunctionNoParamNoResult function){ mFunctionNoParamNoResultHashMap.put(function.mFunctionName,function); return this; }/** * 添加有返回值的方法 * @return */ public FunctionManager addFunction(FunctionWithResultOnly function){ mFunctionWithResultOnlyHashMap.put(function.mFunctionName,function); return this; }/** * 添加有参数的方法 * @return */ public FunctionManager addFunction(FunctionWithParamOnly function){ mFunctionWithParamsOnlyHashMap.put(function.mFunctionName,function); return this; }/** * 添加有参有返回值的方法 * @return */ public FunctionManager addFunction(FunctionWithParamWithResult function){ mFunctionWithParamWithResultHashMap.put(function.mFunctionName,function); return this; }/** * 调用无返回值无参数的方法 * @param funName */ public void invokeNoAll (String funName) throws NullPointerException { if (TextUtils.isEmpty(funName)){ Log.e(TAG,"funName is null !"); }else { if ( null != mFunctionNoParamNoResultHashMap){ FunctionNoParamNoResult function =mFunctionNoParamNoResultHashMap.get(funName); if (null != function){ function.function(); }else { Log.e(TAG,"function is null !"); } }else { throw new NullPointerException("mFunctionNoParamNoResultHashMap can not be null ,please first init FunctionManager !"); } } }/** * 调用有参数的方法 * @param funName */ public < Param> void invokeWithParamOnly (String funName,Param param) throws NullPointerException { if (TextUtils.isEmpty(funName)){ Log.e(TAG,"funName is null !"); }else { if ( null != mFunctionWithParamsOnlyHashMap){ FunctionWithParamOnly< Param> function =mFunctionWithParamsOnlyHashMap.get(funName); if (null != function){ function.function(param); }else { Log.e(TAG,"function is null !"); } }else { throw new NullPointerException("mFunctionWithParamsOnlyHashMap can not be null ,please first init FunctionManager !"); } } }/** * 调用有返回值的方法 * @param funName */ public < Result> Result invokeWithResultOnly (String funName, Class< Result> c) throws NullPointerException { if (TextUtils.isEmpty(funName)){ Log.e(TAG,"funName is null !"); }else { if ( null != mFunctionWithResultOnlyHashMap){ FunctionWithResultOnly function =mFunctionWithResultOnlyHashMap.get(funName); if (null != function){ if ( null != c){ return c.cast(function.function()); }else { return (Result) function.function(); } }else { Log.e(TAG,"function is null !"); } }else { throw new NullPointerException("mFunctionWithParamsOnlyHashMap can not be null ,please first init FunctionManager !"); } } return null; }/** * 调用有参数有返回值的方法 * @param funName */ public < Result,Param> Result invokeWithAll (String funName, Class< Result> c,Param param) throws NullPointerException { if (TextUtils.isEmpty(funName)){ Log.e(TAG,"funName is null !"); }else { if ( null != mFunctionWithParamWithResultHashMap){ FunctionWithParamWithResult< Result,Param> function =mFunctionWithParamWithResultHashMap.get(funName); if (null != function){ if ( null != c){ return c.cast(function.function(param)); }else { return function.function(param); } }else { Log.e(TAG,"function is null !"); } }else { throw new NullPointerException("mFunctionWithParamsOnlyHashMap can not be null ,please first init FunctionManager !"); } } return null; } }

4 在Activity写一个方法

public void setFunctionForFragment(String tag){ if (TextUtils.isEmpty(tag)){ Log.e(MainActivity.class.getSimpleName(),"tag is null !"); return; } BaseFragment fragment = (BaseFragment) fm.findFragmentByTag(tag); FunctionManager functionManager = FunctionManager.getInstance(); functionManager.addFunction(new FunctionNoParamNoResult(FunctionNoParamNoResult) { @Override public void function() { Toast.makeText(MainActivity.this, "无参无返回值", Toast.LENGTH_SHORT).show(); } }); functionManager.addFunction(new FunctionWithResultOnly< String> (FunctionWithResultOnly) { @Override public String function() { return "无参有返回值"; } }); functionManager.addFunction(new FunctionWithParamOnly< String> (FunctionWithParamOnly) { @Override public void function(String o) { Toast.makeText(MainActivity.this, o, Toast.LENGTH_SHORT).show(); } }); functionManager.addFunction(new FunctionWithParamWithResult< String,String> (FunctionWithParamWithResult) { @Override public String function(String o) { return o; } }); fragment.setFunctionManager(functionManager); }

5 编辑一个Fragment基类（实用Fragment的时候直接集成该类就可以了），并绑定上面建立的接口

public class BaseFragment extends Fragment{public FunctionManager mFunctionManager; private MainActivity mainActivity; public void setFunctionManager(FunctionManager mFunctionManager) { this.mFunctionManager = mFunctionManager; }@Override public void onAttach(Context context) { super.onAttach(context); if (context instanceof MainActivity) { mainActivity= (MainActivity) context; mainActivity.setFunctionForFragment(getTag()); } else { throw new RuntimeException(context.toString() + " must implement OnFragmentInteractionListener"); } }@Override public void onDetach() { super.onDetach(); mainActivity = null; }}

6 继承BaseFragment

public class NoParamNoResultFragment extends BaseFragment {private HandlermHandler; public NoParamNoResultFragment(Handlerhandler) { // Required empty public constructor this.mHandler= handler; }@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (getArguments() != null) { } }@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment Viewview= inflater.inflate(R.layout.fragment_no_param_no_result, container, false); view.findViewById(R.id.txt_handle).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Messagemessage = mHandler.obtainMessage(); message.what = 0x123; message.obj = "handle 通信"; mHandler.sendMessage(message); } }); view.findViewById(R.id.txt_noALl).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { mFunctionManager.invokeNoAll(MainActivity.FunctionNoParamNoResult); } }); view.findViewById(R.id.txt_result).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //mFunctionManager.invokeNoAll(MainActivity.FunctionNoParamNoResult); String result =mFunctionManager.invokeWithResultOnly(MainActivity.FunctionWithResultOnly,String.class); Toast.makeText(getActivity(), result, Toast.LENGTH_SHORT).show(); } }); view.findViewById(R.id.txt_param).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { mFunctionManager.invokeWithParamOnly(MainActivity.FunctionWithParamOnly,"有参无返回值"); } }); view.findViewById(R.id.txt_withAll).setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String result =mFunctionManager.invokeWithAll(MainActivity.FunctionWithParamWithResult,String.class,"有参有返回值"); Toast.makeText(getActivity(), result, Toast.LENGTH_SHORT).show(); } }); return view; } }

说明，上述在点击控件的时候，会触发在Activity添加的方法，这样就可以实现Activity与Fragment实时通信，近而实现Fragment之间的通信
https://gitee.com/lzbgit/AppInterface