android 登陆界面

LoginActivity.java

package com.example.ruian;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class LoginActivity extends Activity {

    private EditText m_txtUserName = null;
    private EditText m_txtPwd = null;
    private Button m_butLogin=null;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
      // TODO Auto-generated method stub
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_login);

          findViews();
        setListensers();

     }

     private void findViews(){
         m_txtUserName=(EditText) findViewById(R.id.txtUserName);
         m_txtPwd=(EditText) findViewById(R.id.txtPwd);
         m_butLogin = (Button) findViewById(R.id.butLogin);
      }

     private void setListensers(){
         //Login按钮
         m_butLogin.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
                 butLogin_OnClick(v);
             }
         });
     }

     private void butLogin_OnClick(View v){
         //系统参数
         SharedPreferences share = getSharedPreferences("perference",MODE_PRIVATE);
         //登陆密码---------------------------------------------------------------
         String strLoginPwd_value=share.getString("login_pwd_value","");
         //m_txtPwd.setText(strLoginPwd_value);
         if(strLoginPwd_value.equals("")==true){//为空则设初始值
             strLoginPwd_value=getResources().getString(R.string.loginpwd_init);//默认登陆密码
         }

         String strLoginPwd=m_txtPwd.getText().toString();
         if(strLoginPwd.equals(strLoginPwd_value)==true){
             //登陆成功
              //声明Intent对象，并启动 LoginActivity Activity
             Intent intent = new Intent();
             intent.setClass(LoginActivity.this, MainActivity.class);
              startActivity(intent);
             //从历史堆栈中删除当前Activity，用户点击“返回”按钮键时，不会再返回到这个Activity。
             finish();
         }
         else{
             openDialog("登陆密码错误！","消息");
         }
     }

     //弹出对话框--------------------------------------------------
         private void openDialog(String strMsg, String strTitle){
             new AlertDialog.Builder(this)
                 .setTitle(strTitle)
                 .setMessage(strMsg)
                 .setPositiveButton("确认",
                         new DialogInterface.OnClickListener() {
                             @Override
                             public void onClick(DialogInterface dialog, int which) {
                                 // TODO Auto-generated method stub
                             }
                 })
                 .show();
         }

         //弹出确认、取消 对话框--------------------------------------------------
         private void openDialogOk(String strMsg, String strTitle){
             new AlertDialog.Builder(this)
                 .setTitle(strTitle)
                 .setMessage(strMsg)
                 .setPositiveButton("确认",
                         new DialogInterface.OnClickListener() {
                             @Override
                             public void onClick(DialogInterface dialog, int which) {
                                 // TODO Auto-generated method stub
                                 openDialog("登陆密码错误！-----","消息");
                             }
                 })
                 .setNegativeButton("取消",
                         new DialogInterface.OnClickListener() {
                             @Override
                             public void onClick(DialogInterface dialog, int which) {
                                 // TODO Auto-generated method stub
                                 openDialog("登陆密码错误！=====","消息");
                             }
                 })
                 .show();
         }

}

activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
     >

    <TableRow>
        <TextView
        android:layout_width="fill_parent"
           android:layout_height="wrap_content"
           android:gravity="center"
           android:textSize="20dip"
           android:layout_weight="1"
           android:text="用户登陆" />
    </TableRow>
     <TableRow>
        <TextView
            android:id="@+id/lblUserName"
            android:layout_weight="1"
            android:text="用户名:" />
    </TableRow>
    <TableRow>
        <EditText
            android:id="@+id/txtUserName"
            android:layout_weight="1"
            android:inputType="textPassword">
        </EditText>
    </TableRow>
     <TableRow>
        <TextView
            android:id="@+id/lblPwd"
            android:layout_weight="1"
            android:text="密码:" />
    </TableRow>
    <TableRow>
        <EditText
            android:id="@+id/txtPwd"
            android:layout_weight="1"
            android:inputType="textPassword">
        </EditText>
    </TableRow>
   <TableRow>
           <Button
            android:id="@+id/butLogin"
             android:layout_weight="1"
            android:text="登陆" />

     </TableRow>

</TableLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="loginpwd_init">123456</string>
</resources>

最重要的一步，将此界面设置为启动页。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.ruian"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.ruian.LoginActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="ParaSetActivity"></activity>
        <activity android:name="MainActivity"></activity>
    </application>

</manifest>

说明：

android:name="com.example.ruian.LoginActivity"  这句中的 LoginActivity 即是设置初始界面为登陆页。

<activity android:name="ParaSetActivity"></activity>  这句是设置界面的activity

<activity android:name="MainActivity"></activity> 这句是主界面的activity