Rxjava实践之路[初级篇]
AurPye
8年前
<h2><strong>前言</strong></h2> <p>本章主要讲过滤，如何从发射的Observable中选取想要的内容以及学会更多有用的处理技巧。</p> <h3><strong>正题</strong></h3> <p><strong>1、filter</strong></p> <ul> <li> <p>筛选符合条件的内容</p> <pre> <code class="language-java">/** * 筛选符合条件的内容 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void filterObservable(){ // 使用filter方法过滤内容中不需要的值 Observable.just("A1","B1","A2","C3").filter(new Func1<String, Boolean>() { @Override public Boolean call(String s) { // 条件筛选以“A”开始的内容 return s.startsWith("A"); } }).subscribe(new Action1<String>() { @Override public void call(String s) { // 打印结果 System.out.println("ddddddddddddddddddd filter s = " + s); } }); }</code></pre> 运行结果如下： <pre> <code class="language-java">09-18 14:32:29.978 25356-25356/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddddddd filter s = A1 09-18 14:32:29.978 25356-25356/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddddddd filter s = A2</code></pre> <p><strong>2、take</strong></p> </li> <li> <p>筛选出原始数据中前n个数据发射</p> <pre> <code class="language-java">/** * 筛选出原始数据中前n个数据发射 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void takeObservable(){ // take(n) 提取原数据前n个数据发射 Observable.just("1","2","3","4","5").take(4).subscribe(new Action1<String>() { @Override public void call(String s) { // 打印结果 System.out.println("ddddddddddddddd take s = " + s); } }); }</code></pre> <p>运行结果如下：</p> <pre> <code class="language-java">09-18 14:46:21.894 424-424/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddd take s = 1 09-18 14:46:21.894 424-424/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddd take s = 2 09-18 14:46:21.894 424-424/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddd take s = 3 09-18 14:46:21.895 424-424/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddd take s = 4</code></pre> <p><strong>3、takelast</strong></p> </li> <li> <p>筛选出原始数据中从倒数前n个数据发射</p> <pre> <code class="language-java">/** * 筛选出原始数据中从倒数前n个数据发射 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void takeLastObservable(){ // takeLast(n) 提取原数据倒数前n个数据发射 Observable.just("1","2","3","4","5").takeLast(2).subscribe(new Action1<String>() { @Override public void call(String s) { // 打印结果 System.out.println("dddddddddddddddddd takeLast s = " + s); } }); }</code></pre> </li> </ul> <p><strong>4、distinct</strong></p> <ul> <li> <p>去掉数据中重复值</p> <pre> <code class="language-java">/** * 去掉数据中重复值 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void distinctObservable(){ // 将发射数据重复五遍再去重复 Observable.just("A1","A1","B1","C1","D1","B1","A1").repeat(5).distinct().subscribe(new Action1<String>() { @Override public void call(String s) { // 打印结果 System.out.println("ddddddddddddddddd distinct s = " + s); } }); }</code></pre> 运行结果如下： <pre> <code class="language-java">09-18 14:54:35.616 6187-6187/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddddd distinct s = A1 09-18 14:54:35.616 6187-6187/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddddd distinct s = B1 09-18 14:54:35.617 6187-6187/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddddd distinct s = C1 09-18 14:54:35.617 6187-6187/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddddd distinct s = D1</code></pre> <p><strong>5、skip</strong></p> </li> <li> <p>筛选出原始数据中前n个数据跳过不发射</p> <pre> <code class="language-java">/** * 筛选出原始数据中前n个数据跳过不发射 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void skipObservable(){ // skip(n) 提取原数据前n个数据跳过不发射 Observable.just("1","2","3","4","5").skip(4).subscribe(new Action1<String>() { @Override public void call(String s) { // 打印结果 System.out.println("ddddddddddddddd skip s = " + s); } }); }</code></pre> 运行结果如下： <pre> <code class="language-java">09-18 15:04:10.187 11687-11687/cn.jianke.rxjavafilterdemo I/System.out: ddddddddddddddd skip s = 5</code></pre> </li> </ul> <p><strong>6、skiplast</strong></p> <ul> <li> <p>筛选出原始数据中从倒数前n个数据跳过不发射</p> <pre> <code class="language-java">/** * 筛选出原始数据中从倒数前n个数据跳过不发射 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void skipLastObservable(){ // takeLast(n) 提取原数据倒数前n个数据跳过不发射 Observable.just("1","2","3","4","5").skipLast(2).subscribe(new Action1<String>() { @Override public void call(String s) { // 打印结果 System.out.println("dddddddddddddddddd skipLast s = " + s); } }); }</code></pre> 运行结果如下： <pre> <code class="language-java">09-18 15:05:31.576 11687-11687/cn.jianke.rxjavafilterdemo I/System.out: dddddddddddddddddd skipLast s = 1 09-18 15:05:31.577 11687-11687/cn.jianke.rxjavafilterdemo I/System.out: dddddddddddddddddd skipLast s = 2 09-18 15:05:31.578 11687-11687/cn.jianke.rxjavafilterdemo I/System.out: dddddddddddddddddd skipLast s = 3</code></pre> <p><strong>7、timeout</strong></p> </li> <li> <p>在指定的时间间隔内Observable不发射值的话,监听的原始的Observable时就会触发onError()函数</p> <pre> <code class="language-java">/** * 在指定的时间间隔内Observable不发射值的话,监听的原始的Observable时就会触发onError()函数 * @author leibing * @createTime 2016/09/18 * @lastModify 2016/09/18 * @param * @return */ private void timeoutObservable(){ // 指定4秒后再发射，再指定3秒后如果未发射就触发onError函数 Observable.just("1","2").timer(4, TimeUnit.SECONDS).timeout(3, TimeUnit.SECONDS).subscribe( new Observer<Long>() { @Override public void onCompleted() { System.out.println("dddddddddddddddd timeout onCompleted = "); } @Override public void onError(Throwable e) { System.out.println("dddddddddddddddd timeout e = " + e.getMessage()); } @Override public void onNext(Long aLong) { System.out.println("dddddddddddddddd timeout along = " + aLong); } }); }</code></pre> <p>运行结果如下：</p> <pre> <code class="language-java">09-18 15:28:34.142 25661-25812/cn.jianke.rxjavafilterdemo I/System.out: dddddddddddddddd timeout e = null</code></pre> </li> </ul> <p>demo地址： <a href="/misc/goto?guid=4959716108668670282" rel="nofollow,noindex">RxjavaFilterDemo</a></p> <p> </p> <p> </p> <p>来自：http://www.jianshu.com/p/a7b2142ceffa</p> <p> </p>