Android响应式编程开发RxAndroid（3）：map

╰半夏微凉° 2023-10-17 11:19 6阅读 0赞

**Android响应式编程开发RxAndroid（3）：map**

RxJava中的map通过Function（函数）做一次结果转换，例如把输入源的数据转换处理成大写：

package zhangphil.app;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.util.Log;
    
    import io.reactivex.Observable;
    import io.reactivex.Observer;
    import io.reactivex.android.schedulers.AndroidSchedulers;
    import io.reactivex.disposables.Disposable;
    import io.reactivex.functions.Function;
    import io.reactivex.schedulers.Schedulers;
    
    public class MainActivity extends Activity {
    
        //假设一个数据源
        private String TAG = "zhangphil";
    
        Observer<String> observer = new Observer<String>() {
            @Override
            public void onSubscribe(Disposable d) {
                //Log.d(TAG, d.toString());
            }
    
            @Override
            public void onNext(String s) {
                Log.d(TAG, "onNext - Start");
    
                Log.d(TAG, String.valueOf(s));
    
                Log.d(TAG, "onNext - End");
            }
    
            @Override
            public void onComplete() {
                Log.d(TAG, "onComplete");
            }
    
            @Override
            public void onError(Throwable e) {
                Log.e(TAG, e.toString(), e);
            }
        };
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            //为一个数据源增加一个观察者
            //观察者是observer，observer吐出观察到的数据
            Observable
                    .just("zhang", "phil", "@", "csdn")
                    .subscribeOn(Schedulers.io())
                    .observeOn(AndroidSchedulers.mainThread())
                    .map(function)
                    .subscribe(observer);
        }
    
        private Function<String, String> function = new Function<String, String>() {
            @Override
            public String apply(String s) throws Exception {
                return s.toUpperCase();
            }
        };
    }

代码运行结果输出：

03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - Start
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: ZHANG
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - End
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - Start
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: PHIL
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - End
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - Start
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: @
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - End
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - Start
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: CSDN
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onNext - End
    03-01 20:32:09.354 1581-1581/zhangphil.app D/zhangphil: onComplete

附录：  
1，《Android响应式编程RxAndroid（1）：简单例程》链接地址：[http://blog.csdn.net/zhangphil/article/details/58593782][http_blog.csdn.net_zhangphil_article_details_58593782]  
2，《Android响应式编程开发RxAndroid（2）：简单例程的Android改造 》链接地址：[http://blog.csdn.net/zhangphil/article/details/58597372][http_blog.csdn.net_zhangphil_article_details_58597372]

[http_blog.csdn.net_zhangphil_article_details_58593782]: http://blog.csdn.net/zhangphil/article/details/58593782
[http_blog.csdn.net_zhangphil_article_details_58597372]: http://blog.csdn.net/zhangphil/article/details/58597372