Android开发登陆案例

<?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;@Overrideprotected 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.设置按钮的点击事件bt_login.setOnClickListener(this);//f.回显用户名密码 ??Map<String, String> map = UserInfoUtil.getUserInfo_android(mContext);//获取用户名密码if(map != null){String username = map.get("username");String password = map.get("password");et_username.setText(username);//设置用户名et_password.setText(password);cb_rem.setChecked(true);//设置复选框选中状态}}private void login(){//c.在onclick方法中，获取用户输入的用户名密码和是否记住密码String username = et_username.getText().toString().trim();String password = et_password.getText().toString().trim();boolean isrem = cb_rem.isChecked();//d.判断用户名密码是否为空，不为空请求服务器（省略，默认请求成功）if(TextUtils.isEmpty(username) || TextUtils.isEmpty(password)){Toast.makeText(mContext, "用户名密码不能为空", Toast.LENGTH_SHORT).show();return ;}//请求服务器，后面讲。。。。。。。。。。//e.判断是否记住密码，如果记住，将用户名密码保存本地。???? if(isrem){boolean result = UserInfoUtil.saveUserInfo_android(mContext,username,password);if(result){Toast.makeText(mContext, "用户名密码保存成功", Toast.LENGTH_SHORT).show();}else{Toast.makeText(mContext, "用户名密码保存失败", Toast.LENGTH_SHORT).show(); }}else{Toast.makeText(mContext, "无需保存", Toast.LENGTH_SHORT).show();}}@Overridepublic 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 {//保存用户名密码public static boolean saveUserInfo_android(Context context,String username, String password) {try{String userinfo = username + "##"+ password;//封装用户名密码//得到私有目录下一个文件写入流； name : 私有目录文件的名称 mode： 文件的操作模式， 私有，追加，全局读，全局写FileOutputStream fileOutputStream = context.openFileOutput("userinfo.txt", Context.MODE_PRIVATE);fileOutputStream.write(userinfo.getBytes());//将用户名密码写入文件fileOutputStream.close();return true;}catch (Exception e) {e.printStackTrace();}return false;}//获取用户名密码public static Map<String ,String> getUserInfo_android(Context context){try{//通过context对象获取一个私有目录的文件读取流FileInputStream fileInputStream = context.openFileInput("userinfo.txt");BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));//读取一行中包含用户密码，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;}//保存用户名密码public static boolean saveUserInfo(Context context,String username, String password) {try{String userinfo = username + "##"+ password;//封装用户名密码// String path = "/data/data/com.itheima.login/";//指定保存的路径//通过Context对象获取私有目录的一个路径String path = context.getFilesDir().getPath();System.out.println("...............:"+path);File file = new File(path,"userinfo.txt");//创建fileFileOutputStream fileOutputStream = new FileOutputStream(file);//创建文件写入流fileOutputStream.write(userinfo.getBytes());//将用户名密码写入文件fileOutputStream.close();return true;}catch (Exception e) {e.printStackTrace();}return false;}//获取用户名密码public static Map<String ,String> getUserInfo(Context context){try{// String path = "/data/data/com.itheima.login/";//指定保存的路径//通过Context对象获取私有目录的一个路径String path = context.getFilesDir().getPath();System.out.println("...............:"+path);File file = new File(path,"userinfo.txt");//创建fileFileInputStream fileInputStream = new FileInputStream(file);BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));//读取一行中包含用户密码，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;}}