Android小程序实现简易QQ界面

package com.example.login;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.Toast;
import android.widget.ToggleButton;

public class MainActivity extends Activity {
 //声明组件 
 private EditText username;
 private EditText password;
 private Button login;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  //无标题设置
  requestWindowFeature(Window.FEATURE_NO_TITLE);
  setContentView(R.layout.activity_main);


  //初始化控件，根据Id获取组件对象
  username = (EditText)findViewById(R.id.username);
  password = (EditText)findViewById(R.id.password);
  login = (Button)findViewById(R.id.login);

  //注册监听
  login.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    // 登录
    Log.i("tag", "username:"+username.getText().toString());
    Log.i("tag", "password:"+password.getText().toString());
    Toast t1 = Toast.makeText(getApplicationContext(), "登录成功", Toast.LENGTH_LONG);
    t1.show();  
   }
  });
 }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/aa"
android:orientation="vertical"  
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#55000000"
android:orientation="vertical"
android:paddingLeft="30dp"
android:paddingRight="30dp"  
<LinearLayout
android:layout_marginTop="80dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:orientation="horizontal"  
<ImageView
android:layout_width="43dp"
android:layout_height="43dp"
android:src="@drawable/qq" / 
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="QQ"
android:textColor="#fff"
android:textSize="50dp" / 
</LinearLayout 
<EditText
android:id="@+id/username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:background="@null"
android:hint="QQ号/手机号/邮箱"
android:maxLength="13"
android:singleLine="true"
android:textColor="#fff"
android:textSize="30px"
android:textColorHint="#eee" / 
<View
android:layout_width="match_parent"
android:layout_height="1px"
android:layout_marginTop="10dp"
android:background="#eee" / 
<EditText
android:id="@+id/password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:background="@null"
android:hint="密码"
android:inputType="textPassword"
android:maxLength="13"
android:singleLine="true"
android:textColor="#fff"
android:textSize="30px"
android:textColorHint="#eee" / 
<View
android:layout_width="match_parent"
android:layout_height="1px"
android:layout_marginTop="10dp"
android:background="#eee" / 
<Button
android:id="@+id/login"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:background="@drawable/button_login_bg"
android:text="登录"
android:textColor="#fff"
android:textSize="25px" / 
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:orientation="horizontal"  
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="忘记密码？"
android:textColor="#cc1CA4DE"
android:textSize="20dp" / 
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="right"
android:text="新用户注册"
android:textColor="#cc1CA4DE"
android:textSize="20dp" / 
</LinearLayout 
</LinearLayout 
</LinearLayout