<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@+id/activity_main"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context="luoxiang.com.rxcountdown.MainActivity"
  android:padding="16dp"
  android:orientation="vertical">
 
  <EditText
    android:id="@+id/editText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="請輸入手機號碼"
     />
 
  <Button
    android:id="@+id/btn"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#f97e7e"
    android:text="獲取驗證碼"
    />
</LinearLayout>

package luoxiang.com.rxcountdown;
 
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
 
 
import java.util.concurrent.TimeUnit;
 
import rx.Observable;
import rx.Observer;
import rx.android.schedulers.AndroidSchedulers;
import rx.functions.Action0;
import rx.functions.Func1;
 
 
public class MainActivity extends AppCompatActivity {
 
  private Button mSend;
  private static final String TAG = "MainActivity";
 
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
 
    init();
 
  }
 
  private void init() {
 
    mSend = (Button) findViewById(R.id.btn);
    mSend.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View view) {
        final int count = 30;
 
        Observable.interval(0, 1, TimeUnit.SECONDS)//設置0延遲，每隔一秒發(fā)送一條數(shù)據(jù)
            .take(count+1) //設置循環(huán)11次
            .map(new Func1<Long, Long>() {
              @Override
              public Long call(Long aLong) {
                return count-aLong; //
              }
            })
            .doOnSubscribe(new Action0() {
              @Override
              public void call() {
                mSend.setEnabled(false);//在發(fā)送數(shù)據(jù)的時候設置為不能點擊
 
                mSend.setBackgroundColor(Color.GRAY);//背景色設為灰色
              }
            })
 
            .observeOn(AndroidSchedulers.mainThread())//操作UI主要在UI線程
            .subscribe(new Observer<Long>() {
              @Override
              public void onCompleted() {
                Log.d(TAG, "onCompleted: ");
                mSend.setText("獲取驗證碼");//數(shù)據(jù)發(fā)送完后設置為原來的文字
                mSend.setTextColor(Color.BLACK);
                mSend.setBackgroundColor(Color.parseColor("#f97e7e"));//數(shù)據(jù)發(fā)送完后設置為原來背景色
              }
 
              @Override
              public void onError(Throwable e) {
                e.printStackTrace();
              }
 
              @Override
              public void onNext(Long aLong) { //接受到一條就是會操作一次UI
                Log.d(TAG, "onNext: "+aLong);
                mSend.setText("剩余時間"+aLong+"秒");
                mSend.setEnabled(true);
                mSend.setTextColor(Color.WHITE);
 
              }
            });
      }
    });
  }
 
}