Memory partitioning, memory allocation, constant storage, heap, stack, free storage, global zone [c++][memory management] [reprint]A. In C are divided into these storage areas1. Stack-the release is automatically assigned by the c
is in the system directory, even if it can be manipulated, access to files in this directory is meaningless, such as I write a photo album program, the picture must be placed in the external storage, and if I want to save some of the app's settings data, I was placed in the internal storage of the database directory, So in fact, in the Android file management, w
, but we seem to have no way to operate this path, Because the APK is in the system directory, even if it can be manipulated, access to files in this directory is meaningless, such as I write a photo album program, the picture must be placed in the external storage, and if I want to save some of the app's settings data, I was placed in the internal storage of the
First of all, what is internal storage ?Under the Android platform, it has its own independent data storage rules, under the Windows platform, the application can access or modify the file resources under other applications freely or on the basis of specific access rights.But under the Android platform, all the data of an application is private, and only the appl
ObjectiveI've been talking about Androidui, but it's not over yet, and I'll add it later. Today, I'll talk about other things about data persistence. For an application, it is unavoidable to be able to store the data, and the Android program is no exception. In Android, there are several ways to implement data persistence. The following will be described separately.In Android, data persistence can be achieved in several ways:
Shared Preferences: A sharing Parameter form, a way to save d
As we all know, in the actual work of development, enter the need to write a file to the phone's storage. Since we're talking about cell phone storage space, let's talk about cell phone storage space classification:1: Internal storage spaceRAM
();} catch (FileNotFoundException e) {} catch (IOException e ){}}});} public void saveData () throws IOException {OutputStream out = this. openFileOutput (FILENAME, Context. MODE_PRIVATE);/* parameter 1: file name. * If the file does not exist, Android automatically creates it. The created file is saved in the/data/
Run the program and click "save data". After the Toast is successfully saved. Click the load data button again:
It can be found that the device stored in the
Android newest mobile phone internal storage size, SD card storage size Method
We used to obtain this information in the past.
// Before Android API18: fs. getAvailableBlocks () * fs. getBlockSize ()
Currently:
/** Obtain available system memory **/@ SuppressLint ("NewApi") private String getMemFree () {S
StackThat is, the storage areas for variables allocated by the compiler when needed and automatically cleared when not needed. The variables are usually local variables and function parameters. In a process, the user stack is located at the top of the user's virtual address space, and the compiler uses it to call functions. Like the heap, the user stack can be dynamically expanded and reduced during program execution.
HeapThat is, the
Download source code (download-free credits): Download
You can directly store data in internal storage. By default, files are private to internal storage and cannot beWhen you uninstall an application, the files are removed.You can create and write data in two ways:
Using related methods in java,
Use the related met
File storage (internal storage)once the program is installed in the device, the data/data/package name/That is the internal storage space, external confidentiality.The context provides 2 ways to open an input, output stream
FileInputStream openfileinput (String name)
Learn android from scratch (Data Storage (2) Internal Storage. 36 .)
CallopenFileOutput()With the name of the file and the operating mode. This returnsFileOutputStream. PassOpenFileOutput () creates a FileoutputStream object
Write to the filewrite(). Create a Write object and perform data read/Write operations.
Close the streamclose(). Close the link.The abov
source Download (download points free): DownloadYou can store the data directly into the internal storage, and by default, the file is stored in the internal storage that is private and cannot beOther programs are accessed, and when the application is uninstalled, the files are removed.There are two ways to create and
Some of the application's configuration files need to be stored on the phone. Generally divided into internal storage and SD card storage.One. Internal storage, to FileOutputStreamNew File (Getfilesdir (), "User.txt"); // Open local File preparation record Try { new fi
Android learning notes: internal storage of data; practice Data Reading and writing; storage to Cache for reading and writing; android learning notes
(1) directory structure
(2) Layout file:
(3) tool class for saving and reading data: FileService. java
Package com. example. data_storage_interal.file; import java. io. byteArrayOutputStream; import java. io.
Stacks , which are the stores of variables that are allocated by the compiler when needed, and automatically purged when not needed. The variables inside are usually local variables, function parameters, and so on. In a process, the user stack at the top of the user's virtual address space is compiled with it to implement the function invocation. As with heaps, the user stack can expand and contract dynamically during program execution. Heap , which is the
application to control, generally a new will correspond to a delete. If the programmer does not release it, the operating system will automatically recycle after the program finishes. The heap can be expanded and shrunk dynamically.The free storage area , which is the memory blocks allocated by malloc, is very similar to the heap, but it ends up living with no.Global /static
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