android中的sharedPreferences应用与理解

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1.sharedPreferences中文件的存储格式是xml文件格式

2.新增加的相同键名的记录会覆盖原来的同键名的记录

3.可以存储json格式的数据

一、sharedPreferences封装好的操作代码：

package com.example.text;import android.content.Context;import android.content.SharedPreferences;import android.content.SharedPreferences.Editor;public class FileDB {private SharedPreferences m_preferences;private Editor m_editor;public FileDB() {super();}public boolean setTable(Context context_in, String strTableName) {if (strTableName == null) {return false;}m_preferences = context_in.getSharedPreferences(strTableName,Context.MODE_PRIVATE);m_editor = m_preferences.edit();return true;}public void put(String strAttributeName, String strValue) {m_editor.putString(strAttributeName, strValue);m_editor.commit();}public String get(String strAttributeName) {return new String (m_preferences.getString(strAttributeName, "NULL"));}}

activity中调用示例：

//建表fileDB.setTable(MainActivity.this,"user");//存数据fileDB.put("name", "zhangsan");//取数据String result = fileDB.get("name");fileDB.put("name", "lisi");String result2 = fileDB.get("name");tv1.setText(result);tv2.setText(result2);

二、在sharedPreferences中存储json格式数据

存数据：

public static void saveApkEnalbleArray(Context context,boolean[] booleanArray) {    SharedPreferences prefs = context.getSharedPreferences(APK_ENABLE_ARRAY, Context.MODE_PRIVATE);    JSONArray jsonArray = new JSONArray();    for (boolean b : booleanArray) {      jsonArray.put(b);    }    SharedPreferences.Editor editor = prefs.edit();    editor.putString(APK_ENABLE_ARRAY,jsonArray.toString());    editor.commit();  }

取数据：

public static boolean[] getApkEnableArray(Context context,int arrayLength)  {    SharedPreferences prefs = context.getSharedPreferences(APK_ENABLE_ARRAY, Context.MODE_PRIVATE);    boolean[] resArray=new boolean[arrayLength];     Arrays.fill(resArray, true);    try {        JSONArray jsonArray = new JSONArray(prefs.getString(APK_ENABLE_ARRAY, "[]"));        for (int i = 0; i < jsonArray.length(); i++) {        resArray[i] = jsonArray.getBoolean(i);        }    } catch (Exception e) {        e.printStackTrace();    }       return resArray;  }

调用示例：

boolean[] booleanArray = {true,true,false,false};saveApkEnalbleArray(this,booleanArray);boolean[] resArray = getApkEnableArray(this,2);tv1.setText(resArray[0]+"");

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