Android实现登录

 登录界面布局文件

 1  <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:background="#E6E6E6"
     android:orientation="vertical">
     <ImageView 
         android:id="@+id/iv_head"
         android:layout_width="100dp"
         android:layout_height="100dp"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="40dp"
         android:src="@drawable/ic_launcher11"/>
     <LinearLayout 
         android:id="@+id/layout"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_below="@+id/iv_head"
         android:layout_margin="10dp"
         android:background="#FFFFFF"
         android:orientation="vertical">
         <RelativeLayout 
             android:id="@+id/rl_username"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_margin="10dp">
             <TextView 
                 android:id="@+id/tv_name"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_centerVertical="true"
                 android:text="账号"/>
             <EditText 
                 android:id="@+id/et_number"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_marginLeft="5dp"
                 android:layout_toRightOf="@+id/tv_name"
                 android:background="@null"/>
         </RelativeLayout>
         <View 
             android:layout_width="match_parent"
             android:layout_height="2dp"
             android:background="#E6E6E6"/>
          <RelativeLayout 
             android:id="@+id/rl_userpsd"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_margin="10dp">
             <TextView 
                 android:id="@+id/tv_psw"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_centerVertical="true"
                 android:text="密码"/>
             <EditText 
                 android:id="@+id/et_password"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_marginLeft="5dp"
                 android:layout_toRightOf="@+id/tv_psw"
                 android:inputType="textPassword"
                 android:background="@null"/>
         </RelativeLayout>
         
     </LinearLayout>
     <Button 
         android:id="@+id/btn_login"
         android:onClick="student"
         android:layout_width="match_parent"
         android:layout_height="30dip"
         android:layout_below="@+id/layout"
         android:layout_centerHorizontal="true"
         android:layout_marginLeft="10dp"
         android:layout_marginRight="10dp"
         android:layout_marginTop="20dp"
         android:background="#3C8DC4"
         android:text="登录"
         android:textColor="#FFFFFF"/>
     <Button 
         android:id="@+id/signUp"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="注册"
          android:layout_marginRight="10dp"
         android:background="#E6E6E6"
         android:textColor="#000000"
         android:layout_marginTop="21dp"
         android:layout_centerHorizontal="true"
         android:layout_below="@+id/btn_login"
         android:layout_alignParentRight="true"/>

   
</RelativeLayout>

package com.itcast.test03;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONObject;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.text.TextUtils;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
    private EditText et_username;
    private EditText et_userPsd;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_username = (EditText)findViewById(R.id.et_number);
        et_userPsd = (EditText)findViewById(R.id.et_password);
    }
 public void student(View view){
          String name = et_username.getText().toString();//把EditTextable类型转化为字符串并赋值给name、password
        String password = et_userPsd.getText().toString();
       if(TextUtils.isEmpty(name)||TextUtils.isEmpty(password)){//判断输入的用户和密码是否有为空的
           Toast.makeText(this, "用户名和密码不能为空", 0).show();
           Intent intent01 = new Intent(this,StudentMainActivity.class);
           startActivity(intent01);
       }else{
        try{     
                    
                    HttpClient client = new DefaultHttpClient();//获取HettpClient对象
                    //指定访问地址
                    String path = "http://10.6.78.213:2016/xampp/sse/index.php/home/Index/server_info";
                    HttpPost httpPost = new HttpPost(path);//Post方式请求网络
                    //请求服务器并获取服务器返回的信息
                    HttpResponse response = client.execute(httpPost);
                    //获取状态码
                    int code = response.getStatusLine().getStatusCode();
                    if(code == 200){
                        //将输入流转换成字符串
                        InputStream is = response.getEntity().getContent();
                        //将字节输入转换成字符输入流
                        InputStreamReader in = new InputStreamReader(is);
                        //对字符流对象进行包装
                        BufferedReader bufferedReader = new BufferedReader(in);
                        //StringBuilder(String str)   构造一个字符串生成器，并初始化为指定的字符串内容。
                        StringBuilder builder = new StringBuilder();
                        for (String s = bufferedReader.readLine(); s != null; s = bufferedReader
                                .readLine()) {
                            builder.append(s);
                        }
                        Log.i("cat", ">>>>>>" + builder.toString());
                        String UName;
                        String UPass;
                        /*JsonObject 就是常说的 json。是一种重要的数据传输对象。
                         *  其格式为{"key1":value1,"key2",value2....};key 必须是字符串。
                            很像map对不对，一个key,一个value。
                            因为ajax请求不刷新页面，但配合js可以实现局部刷新，因此json常常被用来作为异步请求的返回对象使用。*/
                        JSONObject jsonObject = new JSONObject(builder.toString());
                        UName = jsonObject.getString("user_name");
                        UPass = jsonObject.getString("user_password");
                       
                        if(UName.equals(name)&&UPass.equals(password))
                        {
                            Toast.makeText(this, "用户名密码输入正确", 0).show();
                            Intent intent = new Intent(this,StudentMainActivity.class);
                            startActivity(intent);
                            }

                        
                        else
                        {
                            Toast.makeText(this, "用户名密码输入不正确", 0).show();
                        }
                    }
                   
                }catch(Exception e){
                    e.printStackTrace();
                   
                }                             
    }      
 }
 
 }

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" 
     android:background="#E6E6E6">

    
        <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                  android:background="#000000">

                <TextView
                    android:id="@+id/textView1"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_centerHorizontal="true"
                    android:layout_centerVertical="true"
                    android:textSize="25sp"
                    android:textColor="#FFFFFF"
                    android:layout_marginLeft="10dp"
                     android:layout_marginRight="10dp"
                    android:text="软件学院的通知和公告" />

            </RelativeLayout>
        </LinearLayout>

         <GridView
            android:id="@+id/gridView"
            android:background="#FFFFFF"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:numColumns="3"
            android:verticalSpacing="10dp"
            android:horizontalSpacing="10dp"
            android:columnWidth="90dp"
            android:stretchMode="columnWidth"
            android:gravity="center" >
        </GridView>

   

</LinearLayout>

1

package com.itcast.test03;

import java.util.ArrayList;
import java.util.HashMap;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class StudentMainActivity extends Activity {
    private GridView gridview;
    private GridView gridview1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_student_main);
        gridview = (GridView)findViewById(R.id.gridView);
        ArrayList<HashMap<String,Object>> lstImageItem = new ArrayList<HashMap<String,Object>>();
        for(int i = 0;i<20;i++){
            HashMap<String,Object> map = new HashMap<String, Object>();
            if(i==1){    
                map.put("ItemImage", R.drawable.ic_launcher02);
                map.put("ItemText", "实践教学管理系统");
                lstImageItem.add(map);
            }else if(i==2){    
                map.put("ItemImage", R.drawable.ic_launcher06);
                map.put("ItemText", "毕业设计管理系统");
                lstImageItem.add(map);
            }else if(i==3){    
                map.put("ItemImage", R.drawable.ic_launcher02);
                map.put("ItemText", "开放实验管理系统");
                lstImageItem.add(map);
            }else if(i==4){    
                map.put("ItemImage", R.drawable.ic_launcher03);
                map.put("ItemText", "实习实训管理系统");
                lstImageItem.add(map);
            }else if(i==5){    
                map.put("ItemImage", R.drawable.ic_launcher05);
                map.put("ItemText", "班级事务管理系统");
                lstImageItem.add(map);
            }else if(i==6){    
                map.put("ItemImage", R.drawable.ic_launcher06);
                map.put("ItemText", "综合实践管理系统");
                lstImageItem.add(map);
            }else if(i==7){    
                map.put("ItemImage", R.drawable.ic_launcher04);
                map.put("ItemText", "其他事物2管理系统");
                lstImageItem.add(map);
            }else if(i==8){    
                map.put("ItemImage", R.drawable.ic_launcher08);
                map.put("ItemText", "其他事物3管理系统");
                lstImageItem.add(map);
            }else if(i==9){    
                map.put("ItemImage", R.drawable.ic_launcher01);
                map.put("ItemText", "其他事物4管理系统");
                lstImageItem.add(map);
            }else if(i==10){    
                map.put("ItemImage", R.drawable.ic_launcher06);
                map.put("ItemText", "毕业设计管理系统");
                lstImageItem.add(map);
            }else if(i==11){    
                map.put("ItemImage", R.drawable.ic_launcher02);
                map.put("ItemText", "开放实验管理系统");
                lstImageItem.add(map);
            }else if(i==12){    
                map.put("ItemImage", R.drawable.ic_launcher03);
                map.put("ItemText", "实习实训管理系统");
                lstImageItem.add(map);
            }else if(i==13){    
                map.put("ItemImage", R.drawable.ic_launcher05);
                map.put("ItemText", "班级事务管理系统");
                lstImageItem.add(map);
            }else if(i==14){    
                map.put("ItemImage", R.drawable.ic_launcher06);
                map.put("ItemText", "综合实践管理系统");
                lstImageItem.add(map);
            }else if(i==15){    
                map.put("ItemImage", R.drawable.ic_launcher04);
                map.put("ItemText", "其他事物2管理系统");
                lstImageItem.add(map);
            }else if(i==15){    
                map.put("ItemImage", R.drawable.ic_launcher08);
                map.put("ItemText", "其他事物3管理系统");
                lstImageItem.add(map);
            }else if(i==17){    
                map.put("ItemImage", R.drawable.ic_launcher01);
                map.put("ItemText", "其他事物4管理系统");
                lstImageItem.add(map);
            }
        }
        SimpleAdapter saImageItems = new SimpleAdapter(this,lstImageItem,R.layout.next_activity_student_main,new String[]{"ItemImage","ItemText"},new int[] {R.id.ItemImage,R.id.ItemText});
        gridview.setAdapter(saImageItems);
        gridview.setOnItemClickListener(new ItemClickListener());
        
    } 
   
    class ItemClickListener implements OnItemClickListener{

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
            HashMap<String, Object> item = (HashMap<String,Object>)arg0.getItemAtPosition(arg2);
            setTitle((String)item.get("ItemText"));
            
        }
        
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
    
}

添加访问权限   
 <uses-permission android:name="android.permission.INTERNET"/>