android storage emulated 0

Android briefly introduces SharedPreference, internal files, and sdcard data storage, SharedPreference Store simple data in xml structure and store it in the data/package name/shared_prefs folder Usage There are three ways to create an object GetSharedPreferences () of Context () GetPreferences () of the Activity () Getdefasharsharedpreferences () of PreferenceManager () Get Data SharedPrefs. getXXX () meth

Objective: Recently studied the Android SQLite database and data sharing between contentprovider programs, we clearly know SQLite database default storage location Data/data/pakage/database directory, There is no security for a mobile phone that already has root, and once exploited will result in a leak of database data, so how can we avoid this? We try to encrypt the database. Select

(int offset);//with the current position as a reference, move to the specified line C.movetofirst ();//move to the first line c.movetolast ();//move to the last row c.movetoposition (int position);//move to the specified line c.movetoprevious ();//move to the previous line C.movetonext ();//move to the next line C.isfirst ();//Whether point to the first c.islast ();// Whether to point to the last C.isbeforefirst ();//whether to point to the first bar before C.isafterlast ();//whether to point t

As a mature mobile phone system, Android provides multiple storage methods for data storage, such as SQLite, SharedPreferences, File, and ContentProvider.,This article mainly introduces SharedPreferences, which is called SP for short. SP is a more lightweight data storage method than databases, it mainly stores simple

name Mydatabaseutil = new Mydatabaseutil (This, "db1.db", NULL, 1); DB1 = This.openorcreatedatabase ("Db1.db", context.mode_private, NULL); /*/data/data/com.example.sqlite/databases must exist, otherwise create an error, and finally databases instead of database, do not forget to add ' s ' *///DB2 = Sqlitedatabase.openorcreatedatabase ("/data/data/com.EXAMPLE.SQLITE/DATABASES/DB2.DB3 ", NULL); /* Create a table and determine if this table already exists, create and initialize the */if (

Data storage is unavoidable in Android development, and today we talk about how to use IO streams to store data.Here we actually operate the IO stream by simulating a small demo of the QQ landing interface.Function Description: Click the button can save user input user name and password, when the click Remember Password, also can be opened in the application the second time, echo the user name and password

problem is solved. Looking back, I was surprised when I looked at the file. The named file was downloaded, but the file size was 0 after the call, fileOutputStream fos = mContext is found. openFileOutput (appName, Context. MODE_WORLD_READABLE | Context. MODE_WORLD_WRITEABLE); used once before saving the file and calling the apk installation code. The openFileOutput method is called again, causing the file content to be cleared, you only need to set t

as:Shared preferences.editor Editor = getsharedpreferences ("Data", Mode_private). Edit ();Editor.putstring ("name", "Qbin");Editor.putstring ("Age", "25");Editor.apply ();　　To read the data step:1, first obtain the Sharedpreferences object;2. Use a series of Get methods in the Sharedpreferences object to read the stored data.　　　　Such as:Sharedpreferences pref = getsharedpreferences ("Data", mode_private);String name = pref.getstring ("name", "");Int age = Pref.getint ("Age",

Most of the time, the software we develop needs to provide users with the software parameter setting function, such as our commonly used QQ, users can set whether to allow strangers to add themselves as friends. For saving software configuration parameters, if the window software is used, we usually use the INI file for saving. If it is a j2se application, we will use the properties property file or XML for saving. For Android applications, how can we

); return result; /** * Android 4.0 calls this method to get the database. * * @see android.content.contextwrapper#openorcreatedatabase (java.lang.String, int, * Andro Id.database.sqlite.SQLiteDatabase.CursorFactory, * android.database.DatabaseErrorHandler) * @ Param Name * @param mode * @param factory * @param errorhandler * * * @Override Public sqlitedatabase openorcreatedatabase (String name, int mode, Cursorfactory factory, Databa

);} /** * * @param filePath * File absolute path * @return */public static localstorage get (String filePath) {createFile (Filep ATH); filepath = filepath;try {properties.load (new FileInputStream (Filepath)); return new Localstorage ();} catch (FileNotFoundException e) {e.printstacktrace ();} catch (IOException e) {e.printstacktrace ();} return null;} private static void CreateFile (String fileName) {File File = new file (fileName); if (!file.exists ()) {String path = File.ge Tabsolutepath ();

in parcel, the problem is that the data I read is either null or always the value at the first offset. What mechanism does Parcel adopt and what form of storage is used, so that I can operate on it at will.Value range of basic data types: boolean 1bit, short 16bit, int 32bit, long 64bit, float 32bit, double 64bit, char 16bit, and byte 8bitFrom this, I can guess that Parcel 32bit is used as the basic unit to store the written variables. 4 byte * 8 = 3

data in parcel, the problem is that the data I read is either null or always the value at the first offset. What mechanism does parcel adopt and what form of storage is used, so that I can operate on it at will. Value range of basic data types: Boolean 1bit, short 16bit, int 32bit, long 64bit, float 32bit, double 64bit, char 16bit, and byte 8bit From this, I can guess that parcel 32bit is used as the basic unit to store the written variables. 4 byte

The sharedpreferences object allows you to save data of the "key-Value Pair" type, such as user ID, birthday, gender, and ID card number. However, sometimes you need to use a traditional file system to store data. For example, you may want to save an article, which will be displayed in your application. In the Android system, you can also use the java. Io package to implement this function. In the Android s

[]Parsehexstr2byte(String hexstr) {if(Hexstr.length () 1)return NULL;byte[] result =New byte[Hexstr.length ()/2]; for(inti =0;i2; i++) {intHigh = Integer.parseint (Hexstr.substring (i*2, i*2+1), -);intLow = Integer.parseint (Hexstr.substring (i*2+1, i*2+2), -); Result[i] = (byte) (High * -+ low); }returnResult } Public StaticStringMD5(String s) {Try{MessageDigest m = messagedigest.getinstance ("MD5"); M.update (S.getbytes ("UTF-8"));byte[] Digest = M.

Storage data (Medium)--sqlite syntax Introduction这篇文章学到的内容：1、sqlite数据存储The database used by Android is SQLite, which is presented here as an example of sqlite3.1 Sqlite3 supported data typesNULL INTEGER REAL TEXT 2 but in fact, Sqlite3 also accepts the following data types:smallint 16 位元的整数。 interger 32 位元的整数。 decimal(p,s) p 精确值和 s 大小的十进位整数，精确值p是指全部有几个数 (digits)大小值，s是指小数点後有几位数。如果没有特别指定，则系统会设为

Sharedpreferences is a tool class for storing simple data in Android. It can be imagined that it is a small cookie that stores simple data types (boolean, int, float, long, and string) in the application's private directory by means of a key-value pair (data/data/package name/shared_prefs/) The XML file that you define yourself.1) Save data// Get Sharedpreferences Object this. Getsharedpreferences ("Shared_file",