一个Android登陆的简单实现

 

   有三个Activity，一个是Login的Activity，一个是正确登陆后的Activity，最后一个是登陆错误后的Activity。其中registerButton没写，因为我还没看android.database这个包，以后我会慢慢的完善它。还有就是检测用户名和密码，用的是最最简陋的equals来判断的，还是因为我没看android.database，呵呵。我现在还是新手，如果哪里有写的不好的，或者是不完善的，请大家多多批评。谢谢大家！下面是全部代码。

 

Login.java

package com.heji.login;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class Login extends Activity {
 
   
 private static Button loginButton;
 private static Button cancelButton;
 private static Button registerButton;
 private static Button exitButton;
    private ButtonListener bl = new ButtonListener();
   
    private EditText et1;
    private EditText et2;
    private Intent intent;
 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login);
       
        //添加登陆按钮监听
        loginButton = (Button)findViewById(R.id.login_ok);
        loginButton.setOnClickListener(bl);

        //添加取消按钮监听
        cancelButton = (Button)findViewById(R.id.login_reset);
        cancelButton.setOnClickListener(bl);
     
        //添加注册按钮监听
        registerButton = (Button)findViewById(R.id.register);
        registerButton.setOnClickListener(bl);
      
        //添加退出按钮监听
        exitButton = (Button)findViewById(R.id.exit);
        exitButton.setOnClickListener(bl);
    }
  private class ButtonListener implements View.OnClickListener {
   public void onClick(View view) {
    // TODO Auto-generated method stub
    if(view == loginButton) {
     et1 = (EditText)findViewById(R.id.username_info);
     et2 = (EditText)findViewById(R.id.password_info);
     
     if((et1.getText().toString()).equals("heji") && (et2.getText().toString()).equals("heji")) {
      intent = new Intent();
      
      //用Bundle来传递当前Activity的内容
      Bundle bundle = new Bundle();
      bundle.putString("USERNAME", et1.getText().toString());
      intent.putExtras(bundle);
      
      intent.setClass(Login.this, Information.class);
      
      //启动Activity
      startActivity(intent);
     }else {
                     intent = new Intent();
      
      intent.setClass(Login.this, ErrorPage.class);
      //启动Activity
      startActivity(intent);
     }
    }else if(view == cancelButton) {
     intent = new Intent();
     //通过Login这个类来启动Login
     intent.setClass(Login.this, Login.class);
     //启动Activity
     startActivity(intent);
    }else if(view == registerButton) {
     
    }else if(view == exitButton) {
        finish();
    }
   }
     }
}

 

Information.java(名字取得很不好，见谅)

package com.heji.login;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class Information extends Activity {

 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  //显示布局
  this.setContentView(R.layout.information);
  
  TextView tv = (TextView)findViewById(R.id.first_page_info);
  
  //获得从上个页面传过来的数据
  Bundle bundle = this.getIntent().getExtras();
  String str = bundle.getString("USERNAME");
  tv.setText(str);
  
  Button button_back = (Button)findViewById(R.id.back);
  button_back.setOnClickListener(new View.OnClickListener() {
   public void onClick(View view) {
    // TODO Auto-generated method stub
    Intent intent = new Intent();
    
    //通过Information这个类来启动Login
    intent.setClass(Information.this, Login.class);
    //启动Activity
    startActivity(intent);
   }
  });
 }
}

 

ErrorPage.java
package com.heji.login;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

 

public class ErrorPage extends Activity {

 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  //显示布局
  this.setContentView(R.layout.errorpage);
  
  Button button_back = (Button)findViewById(R.id.errorback);
  button_back.setOnClickListener(new View.OnClickListener() {
   public void onClick(View view) {
    // TODO Auto-generated method stub
    Intent intent = new Intent();
    
    //通过ErrorPage这个类来启动Login
    intent.setClass(ErrorPage.this, Login.class);
    //启动Activity
    startActivity(intent);
   }
  });
 }
}

 

下面是布局文件：
login.xml
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/welcome_hello"
    />
   
    <TableRow android:orientation="horizontal"
                  android:layout_width="fill_parent"
                  android:layout_height="wrap_content">
                 
         <TextView  
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:text="@string/username"
         />
        
         <EditText android:id="@+id/username_info"
             android:maxLength="8"
             android:maxLines="1"
             android:layout_weight="1.0"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:text=""
         />
    </TableRow>
   
    <TableRow android:orientation="horizontal"
                  android:layout_width="fill_parent"
                  android:layout_height="wrap_content">
                 
         <TextView
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:text="@string/password"
         />
        
         <EditText android:id="@+id/password_info"
             android:password="true"
             android:maxLength="10"
             android:maxLines="1"
             android:layout_weight="1.0"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:text=""
         />
    </TableRow>
   
     <LinearLayout android:orientation="horizontal"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content">
                 
           <Button android:id="@+id/login_ok"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:layout_weight="1.0"
                   android:text="@string/login"
           />
          
           <Button android:id="@+id/login_reset"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:layout_weight="1.0"
                   android:text="@string/reset"
           />
    </LinearLayout>
   
     <LinearLayout android:orientation="horizontal"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content">
                 
           <Button android:id="@+id/register"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:layout_weight="1.0"
                   android:text="@string/register"
           />
           <Button android:id="@+id/exit"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:layout_weight="1.0"
                   android:text="@string/exit"
           />
    </LinearLayout>
   
</TableLayout>

 

information.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
   
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/success_info"
    />
   
<TextView  android:id="@+id/first_page_info"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text=""
    />
   
<Button android:id="@+id/back"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:text="@string/back"
  />

</LinearLayout>

 

errorpage.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
   
<TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/errorpage"
    />
<Button android:id="@+id/errorback"
              android:layout_width="60dip"
              android:layout_height="wrap_content"
              android:text="@string/error_back"
      />
</LinearLayout>

 

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="welcome_hello">Hello,Welcome To Login</string>
    <string name="app_name">Login</string>
    <string name="username">username</string>
    <string name="password">password</string>
    <string name="login">login</string>
    <string name="reset">reset</string>
    <string name="register">register</string>
    <string name="information">congratulation!</string>
    <string name="success_info">Hello Android Developer,You ID Is</string>
    <string name="errorpage">Sorry,You Don't Register,Please By The "BACK" Button To Return The FirstPage,Thank You!!!</string>
    <string name="error_back">BACK</string>
    <string name="back">BACK</string>
    <string name="exit">Exit</string>
</resources>