登录界面 beta版

1.MainActivity.java

 package com.example.administrator.myapplication;

 import android.content.Intent;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.EditText;
 import android.widget.Toast;

 public class MainActivity extends AppCompatActivity {
     EditText et_usercode;
     EditText et_password;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         et_usercode=(EditText)findViewById(R.id.et_usercode);
         et_password=(EditText)findViewById(R.id.et_password);
     }
     //view 代表事件发起者
     public void bt1_onclick(View v)
     {
         //带返回的打开 注册Acivity

         //第一步:构造意图

         Intent intent = new Intent(this,zhuceActivity.class);

         startActivityForResult(intent,1);
     }
     //成员变量
     String usercode;
     String username;
     String password;

     //重写处理返回信息的回调方法

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         super.onActivityResult(requestCode, resultCode, data);

         //处理返回信息
         //1-判断请求码
         if (requestCode==1)
         {
             //2-判断结果码
             if (resultCode==RESULT_OK)
             {
                 //接收返回的注册信息
                 usercode = data.getStringExtra("usercode");
                 username = data.getStringExtra("username");
                 password = data.getStringExtra("userpassword");
             }

         }

     }

     //登录的方法

     public void bt2_onclick(View v)
     {
         //1.取得填写信息
         String uc = et_usercode.getText().toString();
         String pw = et_password.getText().toString();

         // 2.判断是否正确填写
         if (uc.trim().length()==0||pw.trim().length()==0)
         {
             Toast.makeText(MainActivity.this, "用户代码和密码不能为空", Toast.LENGTH_LONG).show();

             return;
         }
         // 3.判断有没有注册信息
         //1-没有找到注册信息 2-填写的用户信息尚未注册
         if (usercode ==null||(usercode !=null && !usercode.equals(uc)))
         {
             Toast.makeText(MainActivity.this, "用户未注册", Toast.LENGTH_LONG).show();

             return;
         }
         // 4.注册信息与登录信息是否匹配

         if (!password.equals(pw))
         {
             Toast.makeText(MainActivity.this, "密码错误", Toast.LENGTH_LONG).show();

             return;
         }
         else
         {
             //可以登录系统
             Toast.makeText(MainActivity.this, "用户验证成功", Toast.LENGTH_LONG).show();

             //跳转到主界面
             startActivity(new Intent(this,TestActivity.class));
         }
     }
 }

2.Actvitymain.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"
     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="com.example.administrator.myapplication.MainActivity"
     android:orientation="vertical">

     <EditText
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="用户代码"
         android:id="@+id/et_usercode"/>
     <EditText
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="密码"
         android:id="@+id/et_password"
         android:inputType="textPassword"/>
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content">
         <Button
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:text="登录"
             android:onClick="bt2_onclick"/>
         <Button
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:text="注册"
             android:onClick="bt1_onclick"/>
     </LinearLayout>
 </LinearLayout>

3.zhuceActivity.xml

 package com.example.administrator.myapplication;

 import android.content.Intent;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.EditText;
 import android.widget.Toast;

 public class zhuceActivity extends AppCompatActivity {
     EditText et_usercode1;
     EditText et_password1;
     EditText et_username1;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_zhuce);

         et_usercode1 = (EditText)findViewById(R.id.et_usercode_1);
         et_password1 = (EditText)findViewById(R.id.et_password_1);
         et_username1 = (EditText)findViewById(R.id.et_username_1);
     }
     //view 代表事件发起
     public void bt1_onclick(View v)
     {
         //返回注册信息
         //用户代码
         String usercode = et_usercode1.getText().toString();
         if(usercode==null||usercode.trim().length()==0)
         {
             Toast.makeText(zhuceActivity.this, "请正确填写用户代码", Toast.LENGTH_LONG).show();

             return;
         }
         String username = et_username1.getText().toString();
         if(username==null||username.trim().length()==0)
         {
             Toast.makeText(zhuceActivity.this, "请正确填写用户名称", Toast.LENGTH_LONG).show();

             return;
         }
         String password = et_password1.getText().toString();
         if(password==null||password.trim().length()==0)
         {
             Toast.makeText(zhuceActivity.this, "请正确填写用户密码", Toast.LENGTH_LONG).show();

             return;
         }

         Intent intent = new Intent();

         intent.putExtra("usercode",usercode);
         intent.putExtra("username",username);
         intent.putExtra("password",password);

         //设置返回信息:1-结果码;2-携带数据的Intent.
         setResult(RESULT_OK,intent);

         finish();
     }

     public void bt2_onclick(View v)
     {
         setResult(RESULT_CANCELED, null);

         finish();
     }
 }

4.activity_zhuce.xml

 <?xml version="1.0" encoding="utf-8"?>
 <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="com.example.administrator.myapplication.zhuceActivity">
     <EditText
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="用户代码"
         android:id="@+id/et_usercode_1"/>
     <EditText
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="用户名称"
         android:id="@+id/et_username_1"
         android:layout_below="@+id/et_usercode_1"/>
     <EditText
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:hint="登录密码"
         android:id="@+id/et_password_1"
         android:layout_below="@+id/et_username_1"
         android:inputType="textPassword"/>
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_alignParentBottom="true">
         <Button
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:text="取消"
             android:onClick="bt2_onclick"/>
         <Button
             android:layout_width="0dp"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:text="确定"
             android:onClick="bt1_onclick"/>
     </LinearLayout>
 </RelativeLayout>

呵呵,导致程序无法运行的错误啊!