corresponding provider.
Roles that are allowed to access the providers' permissions will be described in more detail in the content providers' permissions section.
The user dictionary provider defines the Android. Permission. read_user_dictionary license in its list file. Therefore, if the application wants to read data from this provider, it must apply for this
Contract class)
The contract class defines some features that use content resource identifiers (URIs), column names, intent actions, and content providers to help applicationsProgramA constant of work. Contract classes are not automatically included with providers. providers
, you do not need a provisioner.
2. Read the topic "content providers' basics" carefully to learn more about providers' knowledge.
Next, follow these steps to create the provisioner:
1. Design row-based storage for data. The content provider provides data in two ways:
File data:
Usually, the data put into the
(URI) mode is for a single row of data, use: Android. crusor. Item/
If the resource identification (URI) mode is for multi-row data, use: Android. cursor. DIR/
3. Specify the providers' part: VND.
You must provide
For example, if a provider has the permission of COM. example. App. provider and the table to be exposed is named Table1, the MIME type of multiple rows in Table1 is:
Vnd. Android. cursor. DIR/vnd.com. example. provider. Table1
The MIME t
Like the activity and service components, the contentprovider subclass must be defined using the
1. Authorization (Android: Authorities)
The identifier of the entire provider in the system.
2. Provides the class name (Android: name)
This class implements the contentprovider abstract class.
3. Permission
Attribute that specifies the permissions required for other applications to access the data of the provider:
A. Android. granturipermssions: Temporary Permission ID;
B. Android. Permission: Read
Trainer small project (5) security guard _ using content providers for text message backup correction version, trainer providers
The text message backup class is basically finished in the last section. Iterative code development is required. Code reconstruction and decoupling are required after the development.
Knowledge points that can be learned
① Application
Content providers is one of the four major Android components and plays a very important role. Read the official documentation to explain it:
Content providers manage access to a structured set of data. They encapsulate the data, and provide mechanisms for defining data security.
Content Providers is one of the four major Android components and plays a very important role. Read the official documentation to explain it:
Content providers manage access to a structured set of data. they encapsulate the data, and provide mechanisms for defining data security. c
A content provider manages how to access data stored in the application repository. A content provider is a part of an application. It is often used to make the application interface work on the basis of the data it provides. However, content providers is mainly used for other applications to access and use it using a
(). Getcontentresolver (). Notifychange (Urichange,NULL); }Else{ Throw NewIllegalArgumentException ("URI address is incorrect"); } return NULL; }/** Delete data from the database when the content provider has a data delete operation * @see Android.content.contentprovider#delete (Android.net.Uri, java.lang.String, Java.lang.string[])*/ Public intDelete (Uri Uri, String selection, string[] selectionargs) {intresult=Matcher.match (
Implementation of Android content providers and provision of android content
Next, we will further implement content providers in the introduction to Android content providers.
Each
Android provides five data storage methods:
(1) files: Use fileinputstream and fileoutputstream to operate files. For details about how to use it, refer to the blog "android study note 34: Using files to store data".
(2) shared preferences: used to store data in the form of key-value pairs and save system configuration information. For details about how to use it, see the blog "android study note 35: using shared preferences to store data".
(3) content
The volume provider stores and obtains data so that the data can be accessed by all applications. They are the only way to share data between applications; there is no public storage area accessible to all Android software packages.
Android is a common data type (audio, video, image, personal contact information, and so on) loaded with a lot of content providers. You can see that some of them are listed in
In Android applications, we can use explicit intent (Explicit Intent) to directly access the activity of other applications, but this is limited to the scope of activity, and if you need to use data from other applications, you need to use another component. This is known as content provider (Provider).1. Introduction to content providers (Porviders)
Content Providers, contentproviders
Content providers manage access to a structured set of data. they encapsulate the data, and provide mechanisms for defining data security. content providers are the standard interface that conne
Add two permissions FirstThese two are permissions to modify the desktop's databaseYou can't change it without adding it!Get data directly from content providers,Static arraylistModify the content similarly by the URL to modify,I will not write the code specifically.(8) Launcher3 customized ContentProvider content
1.1. What is a content providerContent provider is one of the four components of Android that can share data from your app to external usersContent providers unify the way data is accessed without having to take different access policies for different data typesContent providers encapsulate data, exposing only the data we want to provide to other programsData cha
1. Calendar ProviderThe calendar Provider is a repository for a user ' s calendar events. The Calendar Provider API allows you to perform query, insert, update,and Delete operations on calendars, events, attendees, reminders, and so on.2. BasicsThe content providers offered by the Android platform (including the Calendar Provider) typically expose data as A set of tables based on arelational database model,
content Provider is primarily used to implement data sharing among different applications , providing a complete set of mechanisms that allow one program to access data from another program while guaranteeing the security of the data being accessed. Currently, using a content provider is a standard way for Android to share data across programs.Unlike two global read-write modes in file storage and sharepr
, its database holds a lot of contact information, if the data are not allowed to access third-party programs, I am afraid that many of the functions of the application will be greatly compromised. In addition to the phone book, there are SMS, media Library and other programs to achieve cross-program data sharing function, and the use of the technology is of course the content provider, the following we will be in-depth discussion of this technology.I
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