接上一篇，加入验证用户名是否已经注冊功能！

仅仅须要改动MainActivity.java:

package com.example.logintest;import java.util.List;import org.w3c.dom.UserDataHandler;import cn.bmob.v3.Bmob;import cn.bmob.v3.BmobQuery;import cn.bmob.v3.listener.FindListener;import cn.bmob.v3.listener.SaveListener;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity {	private EditText mUserName,mPassword;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		Bmob.initialize(this, "8f3ffb2658d8a3366a70a0b0ca0b71b2");		mUserName=(EditText) findViewById(R.id.et_username);		mPassword=(EditText) findViewById(R.id.et_password);	}	public void submit(View view){		final String username=mUserName.getText().toString();		final String password=mPassword.getText().toString();		if(username.equals("")||password.equals("")){			Toast.makeText(this, "用户名或密码不能为空！", 3).show();		}else{			BmobQuery
     
       query =new BmobQuery
      
       ();//查询类			query.addWhereEqualTo("userName", username);//查询条件			query.findObjects(MainActivity.this, new FindListener
       
        () {								@Override				public void onSuccess(List
        
          userlist) {					if(userlist.size()==0){//查询不到，用户名可用						User user=new User();						user.setUserName(username);						user.setUserPassword(password);						user.save(MainActivity.this,new SaveListener() {														@Override							public void onSuccess() {								Toast.makeText(MainActivity.this, "注冊成功！
        
       
      
     

", 3).show(); } @Override public void onFailure(int arg0, String arg1) { Toast.makeText(MainActivity.this, "注冊失败！", 3).show(); } }); }else { Toast.makeText(MainActivity.this, "用户名已被注冊。", 3).show(); } } @Override public void onError(int arg0, String arg1) { // TODO Auto-generated method stub } }); } } }

执行实比例如以下：

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