使用sharedPreferences实现密码登录和注册用户名重复检查

本文通过sharedPreferences实现密码登录以及注册用户是否重复的检查。

无法上传截图，直接上代码。实际项目中涉及用户账户密码的基本都是用数据库保存，而且经过加密（MD5 等）。

LoginActivity.java代码

package com.example.test;

import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.HashMap;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class LoginActivity extends Activity {
private int count;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
Button login = (Button) findViewById(R.id.login);
Button register = (Button) findViewById(R.id.register);
final EditText username = (EditText) findViewById(R.id.username);
final EditText password = (EditText) findViewById(R.id.password);
final TextView tips = (TextView) findViewById(R.id.tips);
//int[] num={1,2};
//final HashMap<String,String> hashMap=new HashMap<String,String>();
count = MySharedPreference.getIntValue(LoginActivity.this, "count");
tips.setText("当前共有" + count + "人注册");
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String strUsername = username.getText().toString();
String strPassword = password.getText().toString();
String defaultPass = MySharedPreference.getStringValue(LoginActivity.this, strUsername);
if (defaultPass.equals(strPassword)) {
//匹配成功登录跳转
Intent intent = new Intent(LoginActivity.this, FaceActivity.class);
startActivity(intent);
finish();
} else {
showMessage("error");
password.setText("");
}
}
});
register.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String strUsername = username.getText().toString();
String strPassword = password.getText().toString();
boolean isNameRepeat = false;
Log.i("czktest", "strUsername=" + strUsername + ",strPassword=" + strPassword);
if (!strUsername.equals("") && !strPassword.equals("")) {
//hashMap.put("one", strUsername);
String[] names = new String[10];//最多保存10个用户
if (count > 0) {
for (int i = 0; i < count; i++) {//检查是否有用户名重复
names[i] = String.valueOf(i);
String name = MySharedPreference.getStringValue(LoginActivity.this, names[i]);
if (name.equals(strUsername)) {
showMessage("exist");
isNameRepeat = true;
break;
}
}
}
if (!isNameRepeat) {
//用户名不重复执行保存（用户名--密码）
MySharedPreference.register(LoginActivity.this, strUsername, strPassword);
//用户名不重复执行保存（数组下标--用户名）
names[count] = String.valueOf(count);
MySharedPreference.saveNames(LoginActivity.th
4000
is, names[count], strUsername);
//用户名不重复执行保存（注册用户数）
count = count + 1;
MySharedPreference.saveCount(LoginActivity.this, "count", count);
tips.setText("当前共有" + count + "人注册");
showMessage("success");
}
} else {
showMessage("");
}
}
});
}

public void showMessage(String str) {
if (str.equals("error")) {
Toast.makeText(LoginActivity.this, "用户名和密码不匹配", Toast.LENGTH_SHORT).show();
} else if (str.equals("success")) {
Toast.makeText(LoginActivity.this, "注册成功", Toast.LENGTH_SHORT).show();
} else if (str.equals("exist")) {
Toast.makeText(LoginActivity.this, "当前用户已被注册", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(LoginActivity.this, "用户名或密码为空", Toast.LENGTH_SHORT).show();
}
}

}

MySharedPreference.java代码

package com.example.test;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.preference.PreferenceManager;

public class MySharedPreference {
private static SharedPreferences preContext = null;

private static SharedPreferences getPreference(Context cx) {
return PreferenceManager.getDefaultSharedPreferences(cx);
}

public static void register(Context cx, String username, String password) {
setValue(cx, username, password);
}

public static void saveNames(Context cx, String username, String password) {
setValue(cx, username, password);
}

public static String getStringValue(Context cx, String key) {
if (preContext == null) {
preContext = getPreference(cx);
}

return preContext.getString(key, "error");
}

private static void setValue(Context cx, String key, String val) {
if (preContext == null) {
preContext = getPreference(cx);
}
Editor ed = preContext.edit();
ed.putString(key, val);
boolean ret = ed.commit();
}

public static void saveCount(Context cx, String key, int count) {
setValue(cx, key, count);
}

public static int getIntValue(Context cx, String key) {
if (preContext == null) {
preContext = getPreference(cx);
}

return preContext.getInt(key, 0);
}

private static void setValue(Context cx, String key, int val) {
if (preContext == null) {
preContext = getPreference(cx);
}
Editor ed = preContext.edit();
ed.putInt(key, val);
boolean ret = ed.commit();
}
}

login.xml布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_marginTop="16dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp">
<LinearLayout

android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">"
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="用户名:"
android:layout_weight="3"
android:gravity="right"/>
<EditText
android:id="@+id/username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"/>"
</LinearLayout>
<LinearLayout

android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="密    码:"
android:layout_weight="3"
android:gravity="right"/>
<EditText
android:id="@+id/password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:layout_weight="1"/>
</LinearLayout>
<Button
android:id="@+id/login"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="登录"
android:textSize="18dp"
android:gravity="center"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/register"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="注册"
android:textSize="16dp"/>
<TextView
android:alpha="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:textSize="16dp"
android:gravity="center"
android:id="@+id/tips" />
<Button
android:id="@+id/forgetpass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="忘记密码"
android:textSize="16dp"
/>
</LinearLayout>
</LinearLayout>