<?xml version="1.0"?>
-<LinearLayout android:paddingTop="@dimen/activity_vertical_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingBottom="@dimen/activity_vertical_margin" android:orientation="vertical" android:layout_height="match_parent" android:layout_width="match_parent" xmlns:tools="http://schemas.android.com/tools" xmlns:android="http://schemas.android.com/apk/res/android">
<EditText android:id="@+id/et_username" android:layout_height="wrap_content" android:layout_width="fill_parent" android:hint="@string/input_username"/>
<EditText android:id="@+id/et_password" android:layout_height="wrap_content" android:layout_width="fill_parent" android:hint="@string/input_password" android:inputType="textPassword" android:layout_marginBottom="10dp" android:layout_marginTop="10dp"/>
-<RelativeLayout android:layout_height="wrap_content" android:layout_width="fill_parent">
<CheckBox android:id="@+id/cb_rem" android:layout_height="wrap_content" android:layout_width="wrap_content" android:text="@string/rem_password" android:layout_alignParentLeft="true" android:layout_centerVertical="true"/>
<Button android:id="@+id/bt_login" android:paddingRight="50dp" android:paddingLeft="50dp" android:layout_height="wrap_content" android:layout_width="wrap_content" android:text="@string/login" android:layout_centerVertical="true" android:layout_alignParentRight="true"/>
</RelativeLayout>
</LinearLayout>

package com.itheima.login;
import java.util.Map;
import com.itheima.login.util.UserInfoUtil;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity implements OnClickListener{
private EditText et_username;
private EditText et_password;
private CheckBox cb_rem;
private Button bt_login;
private Context mContext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = this;
et_username = (EditText) findViewById(R.id.et_username);
et_password = (EditText) findViewById(R.id.et_password);
cb_rem = (CheckBox) findViewById(R.id.cb_rem);
bt_login = (Button) findViewById(R.id.bt_login);
//b.設(shè)置按鈕的點(diǎn)擊事件
bt_login.setOnClickListener(this);
//f.回顯用戶名密碼 ??
Map<String, String> map = UserInfoUtil.getUserInfo_android(mContext);//獲取用戶名密碼
if(map != null){
String username = map.get("username");
String password = map.get("password");
et_username.setText(username);//設(shè)置用戶名
et_password.setText(password);
cb_rem.setChecked(true);//設(shè)置復(fù)選框選中狀態(tài)
}
}
private void login(){
//c.在onclick方法中，獲取用戶輸入的用戶名密碼和是否記住密碼
String username = et_username.getText().toString().trim();
String password = et_password.getText().toString().trim();
boolean isrem = cb_rem.isChecked();
//d.判斷用戶名密碼是否為空，不為空請(qǐng)求服務(wù)器（省略，默認(rèn)請(qǐng)求成功）
if(TextUtils.isEmpty(username) || TextUtils.isEmpty(password)){
Toast.makeText(mContext, "用戶名密碼不能為空", Toast.LENGTH_SHORT).show();
return ;
}
//請(qǐng)求服務(wù)器，后面講。。。。。。。。。。
//e.判斷是否記住密碼，如果記住，將用戶名密碼保存本地。???? 
if(isrem){
boolean result = UserInfoUtil.saveUserInfo_android(mContext,username,password);
if(result){
Toast.makeText(mContext, "用戶名密碼保存成功", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(mContext, "用戶名密碼保存失敗", Toast.LENGTH_SHORT).show(); 
}
}else{
Toast.makeText(mContext, "無需保存", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.bt_login:
login();
break;
default:
break;
}
}
}

package com.itheima.login.util;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;
import android.content.Context;
public class UserInfoUtil {
//保存用戶名密碼
public static boolean saveUserInfo_android(Context context,String username, String password) {
try{
String userinfo = username + "##"+ password;//封裝用戶名密碼
//得到私有目錄下一個(gè)文件寫入流； name : 私有目錄文件的名稱 mode： 文件的操作模式， 私有，追加，全局讀，全局寫
FileOutputStream fileOutputStream = context.openFileOutput("userinfo.txt", Context.MODE_PRIVATE);
fileOutputStream.write(userinfo.getBytes());//將用戶名密碼寫入文件
fileOutputStream.close();
return true;
}catch (Exception e) {
e.printStackTrace();
}
return false;
}
//獲取用戶名密碼
public static Map<String ,String> getUserInfo_android(Context context){
try{
//通過context對(duì)象獲取一個(gè)私有目錄的文件讀取流
FileInputStream fileInputStream = context.openFileInput("userinfo.txt");
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));
//讀取一行中包含用戶密碼，需要解析
String readLine = bufferedReader.readLine();
String[] split = readLine.split("##");
HashMap<String, String> hashMap = new HashMap<String ,String>();
hashMap.put("username", split[0]);
hashMap.put("password", split[1]);
bufferedReader.close();
fileInputStream.close();
return hashMap;
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
//保存用戶名密碼
public static boolean saveUserInfo(Context context,String username, String password) {
try{
String userinfo = username + "##"+ password;//封裝用戶名密碼
// String path = "/data/data/com.itheima.login/";//指定保存的路徑
//通過Context對(duì)象獲取私有目錄的一個(gè)路徑
String path = context.getFilesDir().getPath();
System.out.println("...............:"+path);
File file = new File(path,"userinfo.txt");//創(chuàng)建file
FileOutputStream fileOutputStream = new FileOutputStream(file);//創(chuàng)建文件寫入流
fileOutputStream.write(userinfo.getBytes());//將用戶名密碼寫入文件
fileOutputStream.close();
return true;
}catch (Exception e) {
e.printStackTrace();
}
return false;
}
//獲取用戶名密碼
public static Map<String ,String> getUserInfo(Context context){
try{
// String path = "/data/data/com.itheima.login/";//指定保存的路徑
//通過Context對(duì)象獲取私有目錄的一個(gè)路徑
String path = context.getFilesDir().getPath();
System.out.println("...............:"+path);
File file = new File(path,"userinfo.txt");//創(chuàng)建file
FileInputStream fileInputStream = new FileInputStream(file);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));
//讀取一行中包含用戶密碼，需要解析
String readLine = bufferedReader.readLine();
String[] split = readLine.split("##");
HashMap<String, String> hashMap = new HashMap<String ,String>();
hashMap.put("username", split[0]);
hashMap.put("password", split[1]);
bufferedReader.close();
fileInputStream.close();
return hashMap;
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
}