Demo

AndroidManifest.xml 短信广播权限

<uses-permission android:name="android.permission.RECEIVE_SMS" >
</uses-permission>
<uses-permission android:name="android.permission.READ_SMS" >
</uses-permission>


<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".MainActivity">

    <EditText
            android:id="@+id/phone"
            android:layout_marginTop="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:phoneNumber="true"
            android:maxLength="11"
            android:hint="***"
    />


    <LinearLayout
            android:layout_marginBottom="50dp"
            android:layout_marginTop="50dp"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:background="#fff">
        <Button
                android:textColor="#fff"
                android:background="#F8D775"
                android:id="@+id/button_1"
                android:layout_width="match_parent"
                android:layout_height="50dp"
                android:text="开启监听"/>
    </LinearLayout>
    <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content">
        <Button
                android:id="@+id/button_test"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textColor="#000000"
                android:text="小米手机开启短信权限（读取短信/通知短信）"/>
    </LinearLayout>

    <Button
            android:id="@+id/button_exit"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:text="关闭退出"/>
    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#000000"
            android:text="监听短信："/>

    <TextView
            android:id="@+id/sms_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
</LinearLayout>

public class SMSReceiver extends BroadcastReceiver {

  private static MessageListener mMessageListener;
  public static final String SMS_RECEIVED_ACTION = "android.provider.Telephony.SMS_RECEIVED";

  public SMSBroadcastReceiver() {
    super();
  }

  @Override
  public void onReceive(Context context, Intent intent) {
      if (intent.getAction().equals(SMS_RECEIVED_ACTION)) {
        Object[] pdus = (Object[]) intent.getExtras().get("pdus");
        for(Object pdu:pdus) {
          SmsMessage smsMessage = SmsMessage.createFromPdu((byte [])pdu);
          String sender = smsMessage.getDisplayOriginatingAddress();
          //短信内容
          String content = smsMessage.getDisplayMessageBody();
          String contentFormat="电话号码:" + sender + "\n内容:" + content+"\n------华丽的分割线-----\n";
          if (content.contains("关键字")) {
            //从短信内容中获取验证码
            String code=getCode(content);
             //回调数据
            mMessageListener.onReceived(contentFormat,code);
          }
        }
      }

  }

  //回调接口
  public interface MessageListener {
    public void onReceived(String message,String code);
  }

  public void setOnReceivedMessageListener(MessageListener messageListener) {
    this.mMessageListener = messageListener;
  }

  public static String getCode(String body) {
    String str = Pattern.compile("[^0-9]").matcher(body).replaceAll("");
    return str;
  }
}

`

注册广播监听

private void initSmsReader(){
    //生成广播处理
    smsReceiver = new smsReceiver();
    //实例化过滤器并设置要过滤的广播
    IntentFilter intentFilter = new IntentFilter(SMS_RECEIVED_ACTION);
    //设置优先级
    intentFilter.setPriority(Integer.MAX_VALUE);
    //注册广播
    this.registerReceiver(smsReceiver, intentFilter);

    mSMSBroadcastReceiver.setOnReceivedMessageListener(new SMSReceiver.MessageListener() {
        //监听回调
        @Override
        public void onReceived(String message,String code) {
            //验证码
            String oldText = smsText.getText().toString();
            smsText.setText(message+oldText);
            if(null!=code&& null!=phone){
                // TODO
            }
        }
    });
}
//关闭
private void exit(){
        if(smsReceiver!=null){
            System.out.println("关闭监听");
            //注销短信监听广播
            this.unregisterReceiver(smsReceiver);
            mSMSBroadcastReceiver=null;
        }
        System.exit(0);
    }

Q.E.D.