import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

public static final int MSG_RECEIVER_CODE = 1;
private EditText smsEt;
private Handler handler = new Handler() {
 @Override
 public void handleMessage(Message msg) {
 switch (msg.what) {
  case MSG_RECEIVER_CODE:
  String message= (String) msg.obj;
  smsEt.setText(message);
  smsEt.setSelection(message.length());
  break;
  default:
  break;
 }
 }
};
private MySmsObserver mySmsObserver;

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 smsEt = (EditText) findViewById(R.id.smsEt);
 mySmsObserver = new MySmsObserver(this, handler);
 Uri uri=Uri.parse("content://sms");
 getContentResolver().registerContentObserver(uri,true, mySmsObserver);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
 getMenuInflater().inflate(R.menu.menu_main, menu);
 return true;
}


@Override
protected void onDestroy() {
 super.onDestroy();
 getContentResolver().unregisterContentObserver(mySmsObserver);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
 int id = item.getItemId();

 if (id == R.id.action_settings) {
 return true;
 }

 return super.onOptionsItemSelected(item);
}
}

import android.content.Context;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Handler;
import android.util.Log;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
* Created by Nate on 2015/9/28.
*/
public class MySmsObserver extends ContentObserver {

private Context mContext;
private Handler mHandler;


public MySmsObserver(Context context, Handler handler) {
 super(handler);
 this.mContext = context;
 this.mHandler = handler;
}

@Override
public void onChange(boolean selfChange, Uri uri) {
 super.onChange(selfChange, uri);

 if (uri.toString().equals("content://sms/raw")) {
 return;
 }

 Uri queryUri = Uri.parse("content://sms/inbox");
 String code = "";
 Cursor cursor = mContext.getContentResolver().query(queryUri, null, null, null, "date desc");
 if (cursor != null) {
 if (cursor.moveToFirst()) {
  String address = cursor.getString(cursor.getColumnIndex("address"));
  String message = cursor.getString(cursor.getColumnIndex("body"));

  // TODO: 2015/9/28 這里可以根據(jù)address做一些自己的判斷，比如只有特定的手機號才做判斷

  Log.e("guxuewu", "address:==>" + address + " message:==>" + message);

  // TODO: 2015/9/28 這里可以根據(jù)自己的項目進行特定的正則表達式的編寫 
  Pattern pattern = Pattern.compile("(\\d{6})");
  Matcher matcher = pattern.matcher(message);

  if (matcher.find()) {
  code = matcher.group(0);
  mHandler.obtainMessage(MainActivity.MSG_RECEIVER_CODE, code).sendToTarget();
  }
 }

 cursor.close();
 }


}
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity">


<EditText
 android:id="@+id/smsEt"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_centerHorizontal="true"
 android:ems="10" />

</RelativeLayout>