Android- SharedPreferences的封装
对于大部分初学者来说,如果想利用SharedPreferences进行数据存储的话大部分人(包括本人)应该会这样:
存储:
SharedPreferences sharedPreferences = getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);
Editor editor = sharedPreferences.edit();
editor.putString("username", "Tom");
editor.putInt("password", 123456);
editor.commit();
获取:
SharedPreferences sharedPreferences = getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);
String username = sharedPreferences.getString("username", "");
int password = sharedPreferences.getInt("password", 0);
虽然这样做代码没多少,如果是对于初学者练习来说无伤大雅。但是如果你是做一个项目开发来说,里面使用了大量的数据存数。每次都将上面的代码一遍一遍的重复,估计能让人崩溃。所以,对于实际项目开发来说,最好能将可以封装的工具类封装就进行封装。
下面是一个封装好的SharedPreferences的工具类,如果你有需要直接引用就OK:
package com.example.utl;
import java.util.Map;
import android.content.Context;
import android.content.SharedPreferences;
/**
* 保存信息配置类
*
* @author admin
*/
public class SharedPreferencesHelper {
private SharedPreferences sharedPreferences;
/*
* 保存手机里面的名字
*/private SharedPreferences.Editor editor;
public SharedPreferencesHelper(Context context,String FILE_NAME) {
sharedPreferences = context.getSharedPreferences(FILE_NAME,
Context.MODE_PRIVATE);
editor = sharedPreferences.edit();
}
/**
* 存储
*/
public void put(String key, Object object) {
if (object instanceof String) {
editor.putString(key, (String) object);
} else if (object instanceof Integer) {
editor.putInt(key, (Integer) object);
} else if (object instanceof Boolean) {
editor.putBoolean(key, (Boolean) object);
} else if (object instanceof Float) {
editor.putFloat(key, (Float) object);
} else if (object instanceof Long) {
editor.putLong(key, (Long) object);
} else {
editor.putString(key, object.toString());
}
editor.commit();
}
/**
* 获取保存的数据
*/
public Object getSharedPreference(String key, Object defaultObject) {
if (defaultObject instanceof String) {
return sharedPreferences.getString(key, (String) defaultObject);
} else if (defaultObject instanceof Integer) {
return sharedPreferences.getInt(key, (Integer) defaultObject);
} else if (defaultObject instanceof Boolean) {
return sharedPreferences.getBoolean(key, (Boolean) defaultObject);
} else if (defaultObject instanceof Float) {
return sharedPreferences.getFloat(key, (Float) defaultObject);
} else if (defaultObject instanceof Long) {
return sharedPreferences.getLong(key, (Long) defaultObject);
} else {
return sharedPreferences.getString(key, null);
}
}
/**
* 移除某个key值已经对应的值
*/
public void remove(String key) {
editor.remove(key);
editor.commit();
}
/**
* 清除所有数据
*/
public void clear() {
editor.clear();
editor.commit();
}
/**
* 查询某个key是否存在
*/
public Boolean contain(String key) {
return sharedPreferences.contains(key);
}
/**
* 返回所有的键值对
*/
public Map<String, ?> getAll() {
return sharedPreferences.getAll();
}
}
登录界面:
Activity中应用:
/**
* 登录界面
*
* @author admin
*
*/
public class LoginActivity extends Activity implements OnClickListener {
private EditText username;
private EditText password;
private Button login;// 登录按钮
private CheckBox holdPwd;// 保存用户和密码
private MyDialog mydialog;// 自定义对话框
private SharedPreferencesHelper sharedPreferencesHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_login);
init();
}
/**
* 初始化界面
*/
private void init() {
sharedPreferencesHelper = new SharedPreferencesHelper(
LoginActivity.this, "anhua");
username = (EditText) findViewById(R.id.username);
password = (EditText) findViewById(R.id.password);
holdPwd = (CheckBox) findViewById(R.id.login_hold);
holdPwd.setChecked(true);
//取出存储的值在登陆界面中显示
username.setText(sharedPreferencesHelper.getSharedPreference("username", "").toString().trim());
password.setText(sharedPreferencesHelper.getSharedPreference("password", "").toString().trim());
login = (Button) findViewById(R.id.login);
login.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.login:
login();
break;
default:
break;
}
}
private void login() {
String name = username.getText().toString().trim();
String pwd = password.getText().toString().trim();
//如果复选框被选中则存储账户和密码
if (holdPwd.isChecked()) {
sharedPreferencesHelper.put("username", name);
sharedPreferencesHelper.put("password", pwd);
sharedPreferencesHelper.put("isremember", holdPwd.isChecked());
} else {
//如果复选框未被选中则清除记录的账号和密码
sharedPreferencesHelper.remove("username");
sharedPreferencesHelper.remove("password");
sharedPreferencesHelper.remove("isremember");
}
login.setBackgroundResource(R.drawable.bg_login_submit);
login.setTextColor(getResources().getColor(R.color.white));
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
}
原文网址:https://www.cnblogs.com/1925yiyi/p/7489367.html