Android学习之MiniTwitter记住密码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/btnbg_roundcorner"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin" >

    <TextView
        android:id="@+id/tvUsername"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="@string/tvName"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <EditText
        android:id="@+id/etUsername"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/tvUsername"
        android:layout_below="@+id/tvUsername"
        android:background="@android:drawable/edit_text"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/tvPassword"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/etUsername"
        android:layout_below="@+id/etUsername"
        android:text="@string/tvPassword"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <EditText
        android:id="@+id/etPassword"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/tvPassword"
        android:layout_below="@+id/tvPassword"
        android:layout_marginTop="16dp"
        android:background="@android:drawable/edit_text"
        android:ems="10"
        android:inputType="textPassword" />

    <Button
        android:id="@+id/btnLogin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/etPassword"
        android:layout_below="@+id/etPassword"
        android:layout_marginTop="20dp"
        android:background="#FF72CAE1"
        android:text="@string/btnLogin" />

    <CheckBox
        android:id="@+id/rememberpassword"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/etPassword"
        android:layout_alignTop="@+id/btnLogin"
        android:layout_marginLeft="19dp"
        android:checked="true"
        android:text="@string/remember" />

</RelativeLayout>

<pre name="code" class="html"><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:orientation="vertical"
    android:background="@drawable/loginbg"
    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=".LoginActivity" >

  <include layout="@layout/login_top"/>
 
  <include layout="@layout/login_bottom"/>"

</LinearLayout>

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.text.Editable;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class LoginActivity extends Activity {
private Button btnLogin;
private EditText etUsername;

private EditText etPassword;
private CheckBox rememberpassword;

// 声明一个SharedPreferences用于保存数据
private SharedPreferences setting = null;
private static final String PREFS_NAME = "NamePwd";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        etUsername=(EditText)findViewById(R.id.etUsername);
        etPassword=(EditText)findViewById(R.id.etPassword);
        rememberpassword=(CheckBox)findViewById(R.id.rememberpassword);
        btnLogin=(Button)findViewById(R.id.btnLogin);
        setListener() ;
        getData();
    }
    private void setListener() {
        // 为登录按钮绑定事件
        btnLogin.setOnClickListener(new OnClickListener() {
            String username=etUsername.getText().toString();
            String password=etPassword.getText().toString();
            @Override
            public void onClick(View arg0) {
                if(!(TextUtils.isEmpty(username))&&(TextUtils.isEmpty(password)))
                {
                // 判断用户名和密码
                if ("123".equals(username)&&"123".equals(password))
                {                   
                    // 跳转到首页
                    Intent intent = new Intent(LoginActivity.this,
                            Login2Activity.class);
                    startActivity(intent);
                    finish();
                } 
                }
                else 
                {
                    // 显示错误提示
                    Toast.makeText(getApplicationContext(), "用户名或密码错误",
                            Toast.LENGTH_SHORT).show();
                }
                
            }
        });
    }


    @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;
    }
    protected void onResume() {
        // 在界面显示数据之前得到之前存储的数据
        super.onResume();
        getData();
    }

    /**
     * 获取存储是数据
     */
    private void getData() {
        // 得到sharedpreferences对象
        setting = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
        // 判断是否之前存储过用户名密码
        if (setting.getBoolean("isKeep", false)) {
            // 如果之前存储过，则显示在相应文本框内
            etUsername.setText(setting.getString("username", ""));
        etPassword.setText(setting.getString("password", ""));
        } else {
            // 否则显示空
            etUsername.setText("");
            etPassword.setText("");
        }
    }

}