前一篇文章（也是我在簡(jiǎn)書上的第一篇技術(shù)文章.）講了Android三劍客的基礎(chǔ)用法和簡(jiǎn)單封裝绍撞，有一些封裝只是一筆帶過，還有些用法被遺漏沒講到的得院，所以在這篇里統(tǒng)一做下查漏補(bǔ)缺傻铣。
0x00 先做一下糾正：
https和失敗重連，OkHttp默認(rèn)是支持的祥绞，并不用手動(dòng)去設(shè)置（在OkHttpClient.Builder中已默認(rèn)設(shè)置）非洲，所以O(shè)kHttpClient.Builder的初始化可以簡(jiǎn)化為：
// 創(chuàng)建OkHttpClient
OkHttpClient.Builder builder = new OkHttpClient.Builder()
// 超時(shí)設(shè)置
.connectTimeout(DEFAULT_CONNECT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(DEFAULT_READ_TIMEOUT, TimeUnit.SECONDS)
.writeTimeout(DEFAULT_WRITE_TIMEOUT, TimeUnit.SECONDS)
// cookie管理
.cookieJar(new PersistentCookieJar(new SetCookieCache(), new SharedPrefsCookiePersistor(App.getInstance())));
0x01 Cookie持久化管理
這部分主要參考了這篇文章。
- 不帶持久化
builder.cookieJar(new CookieJar() {
private final HashMap<HttpUrl, List<Cookie>> cookieStore = new HashMap<>();
@Override
public void saveFromResponse(HttpUrl url, List<Cookie> cookies) {
cookieStore.put(url, cookies);
}
@Override
public List<Cookie> loadForRequest(HttpUrl url) {
List<Cookie> cookies = cookieStore.get(url);
return cookies != null ? cookies : new ArrayList<Cookie>();
}
});
這種簡(jiǎn)單的實(shí)現(xiàn)就谜，每次重啟App都會(huì)需要重新登錄怪蔑，不可取。
- 帶持久化
CookieHandler cookieHandler = new CookieManager(
new PersistentCookieStore(context), CookiePolicy.ACCEPT_ALL);
builder.cookieJar(new JavaNetCookieJar(cookieHandler));
這里出現(xiàn)了兩個(gè)類：JavaNetCookieJar和PersistentCookieStore
- JavaNetCookieJar就是對(duì)CookieJar的封裝實(shí)現(xiàn)丧荐，里面實(shí)現(xiàn)了對(duì)Cookie持久化存儲(chǔ)和獲取的調(diào)用邏輯缆瓣，OkHttp已經(jīng)幫我們實(shí)現(xiàn)了這個(gè)類，需要引入下面這個(gè)包:
compile 'com.squareup.okhttp3:okhttp-urlconnection:3.5.0'
PersistentCookieStore是具體實(shí)現(xiàn)Cookie持久化的類虹统，使用的是SharedPreferences弓坞，具體代碼實(shí)現(xiàn)可參考這篇。
當(dāng)然车荔，如果你想通過數(shù)據(jù)庫實(shí)現(xiàn)持久化渡冻，也可以自己封裝一個(gè)類似的類去實(shí)現(xiàn)。再介紹一個(gè)封裝了Cookie持久化的第三方庫（推薦）
ClearableCookieJar cookieJar = new PersistentCookieJar(
new SetCookieCache(), new SharedPrefsCookiePersistor(context));
builder.cookieJar(cookieJar);
需要引入下面這個(gè)包：
compile 'com.github.franmontiel:PersistentCookieJar:v1.0.0
0x02. 攔截器
-
addInterceptor和addNetworkInterceptor的區(qū)別
前一篇文章有同學(xué)問到兩者的區(qū)別忧便，okHttp官方對(duì)攔截器做了解釋族吻，并給了一張圖，感覺挺一目了然的。
Paste_Image.png
兩種攔截器簡(jiǎn)單來說就是調(diào)用時(shí)機(jī)的區(qū)別超歌，應(yīng)用攔截器調(diào)用時(shí)機(jī)較早砍艾，也就是進(jìn)入chain.proceed的遞歸較早，相應(yīng)的完成遞歸得到response會(huì)較晚巍举；而網(wǎng)絡(luò)攔截器則相反脆荷，request請(qǐng)求調(diào)用時(shí)機(jī)較晚，會(huì)較早完成chain.proceed遞歸調(diào)用懊悯，得到response的時(shí)機(jī)較早蜓谋。
簡(jiǎn)單來說就是應(yīng)用攔截器較上層，而網(wǎng)絡(luò)攔截器較底層炭分，所有攔截器就是一個(gè)由淺入深的遞歸調(diào)用桃焕。具體還是得看源碼。 Http Header
可以通過這個(gè)攔截器為Request添加全局統(tǒng)一的Header捧毛。
/**
* 網(wǎng)絡(luò)請(qǐng)求公共頭信息插入器
*
* Created by XiaoFeng on 17/1/18.
*/
public class HttpHeaderInterceptor implements Interceptor {
@Override
public Response intercept(Chain chain) throws IOException {
Request original = chain.request();
Request request = original.newBuilder()
.header("User-Agent", "Android, xxx")
.header("Accept", "application/json")
.header("Content-type", "application/json")
.method(original.method(), original.body())
.build();
return chain.proceed(request);
}
}
- 公共參數(shù)
主要參考這篇
/**
* 網(wǎng)絡(luò)請(qǐng)求公共參數(shù)插入器
* <p>
* Created by XiaoFeng on 2017/1/25.
*/
public class CommonParamsInterceptor implements Interceptor {
@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
if (request.method().equals("GET")) {
HttpUrl httpUrl = request.url().newBuilder()
.addQueryParameter("version", "xxx")
.addQueryParameter("device", "Android")
.addQueryParameter("timestamp", String.valueOf(System.currentTimeMillis()))
.build();
request = request.newBuilder().url(httpUrl).build();
} else if (request.method().equals("POST")) {
if (request.body() instanceof FormBody) {
FormBody.Builder bodyBuilder = new FormBody.Builder();
FormBody formBody = (FormBody) request.body();
for (int i = 0; i < formBody.size(); i++) {
bodyBuilder.addEncoded(formBody.encodedName(i), formBody.encodedValue(i));
}
formBody = bodyBuilder
.addEncoded("version", "xxx")
.addEncoded("device", "Android")
.addEncoded("timestamp", String.valueOf(System.currentTimeMillis()))
.build();
request = request.newBuilder().post(formBody).build();
}
}
return chain.proceed(request);
}
}
- 緩存策略
/**
* 網(wǎng)絡(luò)請(qǐng)求緩存策略插入器
*
* Created by XiaoFeng on 17/1/17.
*/
public class HttpCacheInterceptor implements Interceptor {
@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
// 無網(wǎng)絡(luò)時(shí)覆旭，始終使用本地Cache
if (!NetworkUtil.isNetworkConnected()) {
request = request.newBuilder()
.cacheControl(CacheControl.FORCE_CACHE)
.build();
}
Response response = chain.proceed(request);
if (NetworkUtil.isNetworkConnected()) {
// 有網(wǎng)絡(luò)時(shí)，設(shè)置緩存過期時(shí)間0個(gè)小時(shí)
int maxAge = 0;
response.newBuilder()
.header("Cache-Control", "public, max-age=" + maxAge)
.removeHeader("Pragma") // 清除頭信息岖妄，因?yàn)榉?wù)器如果不支持，會(huì)返回一些干擾信息寂祥，不清除下面無法生效
.build();
} else {
// 無網(wǎng)絡(luò)時(shí)荐虐，設(shè)置緩存過期超時(shí)時(shí)間為4周
int maxStale = 60 * 60 * 24 * 28;
response.newBuilder()
.header("Cache-Control", "public, only-if-cached, max-stale=" + maxStale)
.removeHeader("Pragma")
.build();
}
return response;
}
}
- 調(diào)試工具
使用的是Facebook推出的一個(gè)集成到Chrome中的調(diào)試工具，需要引入下面兩個(gè)庫：
compile 'com.facebook.stetho:stetho:1.4.1'
compile 'com.facebook.stetho:stetho-okhttp3:1.4.1'
在Application中初始化就可以用了
Stetho.initializeWithDefaults(this);
如何調(diào)試丸凭？
- 打開Chrome瀏覽器
- 地址欄輸入
chrome://inspect - 進(jìn)入頁面后福扬，在左邊的DevTools -> Devices -> Remote Target下，可以找到你連接的手機(jī)設(shè)備惜犀，點(diǎn)開后就會(huì)出現(xiàn)調(diào)試頁面了铛碑，后面就自己研究吧，不光可以調(diào)試網(wǎng)絡(luò)請(qǐng)求虽界，還可以查看手機(jī)中的數(shù)據(jù)庫和SharePreference等持久化文件汽烦，而且不用root，很強(qiáng)大莉御！
0x03. FastJson解析庫封裝
網(wǎng)上很多介紹retrofit的文章撇吞，對(duì)網(wǎng)絡(luò)請(qǐng)求返回的結(jié)果，使用的都是默認(rèn)的Gson庫礁叔，雖然可以滿足大部分人的需求牍颈，但是有些對(duì)性能要求高一點(diǎn)的人，還是習(xí)慣使用FastJson庫做解析琅关，這里就講講如何把默認(rèn)的Gson庫替換成FastJson庫煮岁。
首先，默認(rèn)Gson庫的設(shè)置是這樣的：
Retrofit retrofit = new Retrofit.Builder()
.client(builder.build())
.addConverterFactory(GsonConverterFactory.create())
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.baseUrl(BASE_URL)
.build();
用FastJson庫替換后是這樣的：
Retrofit retrofit = new Retrofit.Builder()
.client(builder.build())
.addConverterFactory(FastJsonConvertFactory.create())
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.baseUrl(BASE_URL)
.build();
是不是很像，沒錯(cuò)画机，就是把ConverterFactory替換了一下而已冶伞。
至于FastJsonConvertFactory的實(shí)現(xiàn)，其實(shí)就是仿造GsonConverterFactory的源碼來寫的色罚，并不復(fù)雜碰缔。
主要有三個(gè)類：
- 工廠類：FastJsonConvertFactory，里面就是分別創(chuàng)建了Request和Response的轉(zhuǎn)換類戳护。
/**
*
* Created by XiaoFeng on 2017/1/17.
*/
public class FastJsonConvertFactory extends Converter.Factory {
public static FastJsonConvertFactory create() {
return new FastJsonConvertFactory();
}
@Override
public Converter<?, RequestBody> requestBodyConverter(Type type, Annotation[] parameterAnnotations, Annotation[] methodAnnotations, Retrofit retrofit) {
return new FastJsonRequestConverter<>();
}
@Override
public Converter<ResponseBody, ?> responseBodyConverter(Type type, Annotation[] annotations, Retrofit retrofit) {
return new FastJsonResponseConverter<>(type);
}
}
- Request轉(zhuǎn)換類：FastJsonRequestConverter
/**
*
* Created by XiaoFeng on 2017/1/17.
*/
public class FastJsonRequestConverter<T> implements Converter<T, RequestBody> {
private static final MediaType MEDIA_TYPE = MediaType.parse("application/json; charset=UTF-8");
private static final Charset UTF_8 = Charset.forName("UTF-8");
@Override
public RequestBody convert(T value) throws IOException {
return RequestBody.create(MEDIA_TYPE, JSON.toJSONBytes(value));
}
}
- Response轉(zhuǎn)換類：FastJsonResponseConverter
/**
*
* Created by XiaoFeng on 2017/1/17.
*/
public class FastJsonResponseConverter<T> implements Converter<ResponseBody, T> {
private final Type type;
public FastJsonResponseConverter(Type type) {
this.type = type;
}
@Override
public T convert(ResponseBody value) throws IOException {
BufferedSource buffer = Okio.buffer(value.source());
String s = buffer.readUtf8();
buffer.close();
return JSON.parseObject(s, type);
}
}
是不是很簡(jiǎn)單金抡，如果想再換成別的第三方j(luò)son解析庫，照著這個(gè)寫就可以了腌且。
0x04. 生命周期
上一篇中還有同學(xué)提到RxJava的生命周期管理梗肝，防止內(nèi)存泄漏，這個(gè)可以直接使用第三方庫铺董，參考這篇巫击。
一般引用下面兩個(gè)庫就夠了：
compile 'com.trello:rxlifecycle:1.0'
compile 'com.trello:rxlifecycle-components:1.0'
有兩種使用方式：
1. 自動(dòng)取消訂閱，使用bindToLifecycle精续。
需要繼承至RxActivity或者RxFragment等基類坝锰。
@Override
protected void onStart() {
super.onStart();
// Using automatic unsubscription, this should determine that the correct time to
// unsubscribe is onStop (the opposite of onStart).
Observable.interval(1, TimeUnit.SECONDS)
.doOnUnsubscribe(new Action0() {
@Override
public void call() {
Log.i(TAG, "Unsubscribing subscription from onStart()");
}
})
// 因?yàn)閎indToLifecycle是在onStart的時(shí)候調(diào)用，所以在onStop的時(shí)候自動(dòng)取消訂閱
.compose(this.<Long>bindToLifecycle())
.subscribe(new Action1<Long>() {
@Override
public void call(Long num) {
Log.i(TAG, "Started in onStart(), running until in onStop(): " + num);
}
});
}
從下面這段核心函數(shù)可以看清自動(dòng)取消訂閱的規(guī)則重付，就是在哪個(gè)生命周期內(nèi)調(diào)用bindToLifecycle顷级，就在與其對(duì)應(yīng)的結(jié)束生命周期函數(shù)調(diào)用時(shí)自動(dòng)取消訂閱。
private static final Func1<ActivityEvent, ActivityEvent> ACTIVITY_LIFECYCLE =
new Func1<ActivityEvent, ActivityEvent>() {
@Override
public ActivityEvent call(ActivityEvent lastEvent) {
switch (lastEvent) {
case CREATE:
return ActivityEvent.DESTROY;
case START:
return ActivityEvent.STOP;
case RESUME:
return ActivityEvent.PAUSE;
case PAUSE:
return ActivityEvent.STOP;
case STOP:
return ActivityEvent.DESTROY;
case DESTROY:
throw new OutsideLifecycleException("Cannot bind to Activity lifecycle when outside of it.");
default:
throw new UnsupportedOperationException("Binding to " + lastEvent + " not yet implemented");
}
}
};
2. 手動(dòng)取消訂閱确垫，使用bindUntilEvent弓颈。
需要繼承至RxActivity或者RxFragment等基類。
@Override
protected void onResume() {
super.onResume();
// `this.<Long>` is necessary if you're compiling on JDK7 or below.
// If you're using JDK8+, then you can safely remove it.
Observable.interval(1, TimeUnit.SECONDS)
.doOnUnsubscribe(new Action0() {
@Override
public void call() {
Log.i(TAG, "Unsubscribing subscription from onResume()");
}
})
// 手動(dòng)設(shè)置在Activity onDestroy的時(shí)候取消訂閱
.compose(this.<Long>bindUntilEvent(ActivityEvent.DESTROY))
.subscribe(new Action1<Long>() {
@Override
public void call(Long num) {
Log.i(TAG, "Started in onResume(), running until in onDestroy(): " + num);
}
});
}
3. 自定義RxActivity/RxFragment
直接繼承RxActivity/RxFragment有時(shí)會(huì)碰到問題删掀，因?yàn)橛锌赡鼙旧硪呀?jīng)有一個(gè)基類需要繼承翔冀，java不能多繼承。不過不要慌披泪，我們可以自定義一個(gè)自己的基類纤子，實(shí)現(xiàn)方式參考RxActivity。
public abstract class RxActivity extends Activity implements LifecycleProvider<activityevent> {
private final BehaviorSubject<activityevent> lifecycleSubject = BehaviorSubject.create();
public RxActivity() {
}
@NonNull
@CheckResult
public final Observable<activityevent> lifecycle() {
return this.lifecycleSubject.asObservable();
}
@NonNull
@CheckResult
public final <t> LifecycleTransformer<t> bindUntilEvent(@NonNull ActivityEvent event) {
return RxLifecycle.bindUntilEvent(this.lifecycleSubject, event);
}
@NonNull
@CheckResult
public final <t> LifecycleTransformer<t> bindToLifecycle() {
return RxLifecycleAndroid.bindActivity(this.lifecycleSubject);
}
@CallSuper
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.lifecycleSubject.onNext(ActivityEvent.CREATE);
}
@CallSuper
protected void onStart() {
super.onStart();
this.lifecycleSubject.onNext(ActivityEvent.START);
}
@CallSuper
protected void onResume() {
super.onResume();
this.lifecycleSubject.onNext(ActivityEvent.RESUME);
}
@CallSuper
protected void onPause() {
this.lifecycleSubject.onNext(ActivityEvent.PAUSE);
super.onPause();
}
@CallSuper
protected void onStop() {
this.lifecycleSubject.onNext(ActivityEvent.STOP);
super.onStop();
}
@CallSuper
protected void onDestroy() {
this.lifecycleSubject.onNext(ActivityEvent.DESTROY);
super.onDestroy();
}
}
突然發(fā)現(xiàn)寫文章真是一個(gè)知識(shí)梳理款票，自我學(xué)習(xí)的好方法计福，比沒有目的性的看很多技術(shù)文章有用很多倍，極力推薦有能力的同學(xué)都去嘗試寫屬于自己的技術(shù)博客徽职。^ ^
參考：
https://gold.xitu.io/entry/572ed42ddf0eea0063186e1f
https://gist.github.com/franmontiel/ed12a2295566b7076161
https://gold.xitu.io/entry/5825300b2f301e005c47fac5
http://www.codexiu.cn/android/blog/39432/
http://androidxx.ren/forum.php?mod=viewthread&tid=19
https://gold.xitu.io/entry/58290ea2570c35005878ce8f
