Android Retrofit使用教程(三):Retrofit与RxJava初相逢

上一篇文章讲述了Retrofit的基本使用,包括GET,POST等请求.今天的文章中Retrofit要与RxJava配合使用.

了解RxJava

RxJava有种种好处,我不在这里一一讲述.这里我只给出一个使用RxJava的例子.

接下来的文章,我也会写RxJava的进一步使用的.

案例说明

该例子是获取手机上安装的APP,然后列表显示包括名称,图标,安装时间等信息.

上代码

下面是自定义的AppInfo类,包含名称,图标,安装时间,版本号,版本名称等属性.

[代码]java代码：

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public class AppInfo {        private String name;        private String installTime;        private int versionCode;        private String versionName;        private Drawable icon;        public String getName() {         return name;     }        public void setName(String name) {         this.name = name;     }        public String getInstallTime() {         return installTime;     }        public void setInstallTime(String installTime) {         this.installTime = installTime;     }        public int getVersionCode() {         return versionCode;     }        public void setVersionCode(int versionCode) {         this.versionCode = versionCode;     }        public String getVersionName() {         return versionName;     }        public void setVersionName(String versionName) {         this.versionName = versionName;     }        public Drawable getIcon() {         return icon;     }        public void setIcon(Drawable icon) {         this.icon = icon;     }        @Override     public String toString() {         return "AppInfo{" +                 "name='" + name + '\'' +                 ", installTime='" + installTime + '\'' +                 ", versionCode='" + versionCode + '\'' +                 ", versionName='" + versionName + '\'' +                 ", icon=" + icon +                 '}';     } }

下面是获取AppLie表的代码,封装为工具类使用:

[代码]java代码：

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public class AppUtil {        /**      * 获取已安装的APP的列表      * @param context 上下文      * @return AppInfo列表      */     public static List<appinfo> getAppList(Context context){         List<appinfo> appInfoList = new ArrayList<>();         List<packageinfo> packages = context.getPackageManager()                 .getInstalledPackages(PackageManager.GET_ACTIVITIES);         for (PackageInfo packageInfo : packages) {             AppInfo appInfo = new AppInfo();             appInfo.setName(packageInfo.applicationInfo                     .loadLabel(context.getPackageManager())                     .toString());             appInfo.setIcon(packageInfo.applicationInfo                     .loadIcon(context.getPackageManager()));             appInfo.setInstallTime(getFormatTime(packageInfo.firstInstallTime));             appInfo.setVersionCode(packageInfo.versionCode);             appInfo.setVersionName(packageInfo.versionName);             appInfoList.add(appInfo);         }         return appInfoList;     }        public static String getFormatTime(long time){         if (time <= 0){             return "";         }         return SimpleDateFormat.getDateInstance(DateFormat.FULL).format(new Date(time));     } }</packageinfo></appinfo></appinfo>

不使用RxJava怎么做?

我们在不适用RxJava时怎么做?通常新建一个子线程去执行任务,然后回调更新界面,对不对?

[代码]java代码：

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private void getByNormal() {     refreshLayout.setRefreshing(true);     infoList.clear();     appAdapter.notifyDataSetChanged();     new AsyncTask<void, void,="" list<appinfo="">>(){            @Override         protected List<appinfo> doInBackground(Void... params) {             return AppHelper.getHelper().getListByNormal(MainActivity.this);         }            @Override         protected void onPostExecute(List<appinfo> appInfos) {             infoList.addAll(appInfos);             appAdapter.notifyDataSetChanged();             refreshLayout.setRefreshing(false);         }     }; }</appinfo></appinfo></void,>

使用RxJava

使用RxJava是这样来写代码的:

1.创建Observable

[代码]java代码：

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public Observable<list<appinfo>> getListByRxJava(final Context context){     Observable<list<appinfo>> observer = Observable.create(             new Observable.OnSubscribe<list<appinfo>>() {                 @Override                 public void call(Subscriber<!--? super List<AppInfo-->> subscriber) {                     List<appinfo> infoList = AppUtil.getAppList(context);                     subscriber.onNext(infoList);                     subscriber.onCompleted();                 }     });     return observer; }</appinfo></list<appinfo></list<appinfo></list<appinfo>

 

2.在界面出调用

[代码]java代码：

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private void getByRxJava() {     refreshLayout.setRefreshing(true);     infoList.clear();     appAdapter.notifyDataSetChanged();     AppHelper.getHelper().getListByRxJava(this)             .subscribeOn(Schedulers.io())             .observeOn(AndroidSchedulers.mainThread())             .subscribe(new Subscriber<list<appinfo>>() {                 @Override                 public void onCompleted() {                     appAdapter.notifyDataSetChanged();                     refreshLayout.setRefreshing(false);                 }                    @Override                 public void onError(Throwable e) {                    }                    @Override                 public void onNext(List<appinfo> list) {                     infoList.addAll(list);                 }             }); }</appinfo></list<appinfo>

看结果

这个Demo的源码在此:RxJavaDemo

在Retrofit中使用RxJava

上次我们获取手机的归属地时的PhoneService中是这样写的:

[代码]java代码：

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@GET("/apistore/mobilenumber/mobilenumber") Call<phoneresult> getResult(@Header("apikey") String apikey,                             @Query("phone") String phone);</phoneresult>

返回了一个Call对象,使用RxJava我们则返回一个可被观测的PhoneResult:Observable<PhoneResult>,如下:

[代码]java代码：

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@GET("/apistore/mobilenumber/mobilenumber") Observable<phoneresult> getPhoneResult(@Header("apikey") String apikey,                                        @Query("phone") String phone);</phoneresult>

为了能返回此对象,我们需要在创建Retrofit对象时添加一个RxJava对象的Adapter来自动完成:

[代码]java代码：

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Retrofit retrofit = new Retrofit.Builder()         .baseUrl(BASE_URL)         .addCallAdapterFactory(RxJavaCallAdapterFactory.create())         .addConverterFactory(GsonConverterFactory.create())         .build();

为此,还封装了一个单例模式的PhoneApi类:

[代码]java代码：

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/**  * 手机号相关的API  * Created by Asia on 2016/3/24 0024.  */ public class PhoneApi {        /**      * HOST地址      */     public static final String BASE_URL = "http://apis.baidu.com";     /**      * 开发者Key      */     public static final String API_KEY = "8e13586b86e4b7f3758ba3bd6c9c9135";        /**      * 获取PhoneApi实例      * @return      */     public static PhoneApi getApi(){         return ApiHolder.phoneApi;     }        static class ApiHolder{         private static PhoneApi phoneApi = new PhoneApi();     }        private PhoneService service;        private PhoneApi(){         Retrofit retrofit = new Retrofit.Builder()                 .baseUrl(BASE_URL)                 .addCallAdapterFactory(RxJavaCallAdapterFactory.create())                 .addConverterFactory(GsonConverterFactory.create())                 .build();         service = retrofit.create(PhoneService.class);     }        /**      * 获取PhoneService实例      * @return      */     public PhoneService getService(){         return service;     } }

下面就是使用去获取手机的归属地啦:

[代码]java代码：

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phoneService.getPhoneResult(PhoneApi.API_KEY, number)         .subscribeOn(Schedulers.newThread())    //子线程访问网络         .observeOn(AndroidSchedulers.mainThread())  //回调到主线程         .subscribe(new Observer<phoneresult>() {             @Override             public void onCompleted() {}                @Override             public void onError(Throwable e) {}                @Override             public void onNext(PhoneResult result) {                 if (result != null && result.getErrNum() == 0) {                     PhoneResult.RetDataEntity entity = result.getRetData();                     resultView.append("地址：" + entity.getCity());                 }             }         }); }</phoneresult>

运行一下吧,结果是同样的哈.