The Android background application can now communicate with any Restful web services that adhere to the same SSO federation. The certificates of the servers that host the web services are procured from the same certificate authority that shipped with the phone.
On reception of a request, the SSO token is extracted from the request. The web service calls upon the SSO system to authorize the operation. On reception of the data, the symmetric cipher described in bullet 3 above is used to encrypt the data before it reaches any local persistent storehouse.
Data is returned to the user facing application. Additional security notes: 1. As such, the private key has never left the phone nor has it been transferred over any network. The certificate of the user must at least be registered once in the SSO application. This could be done at install time of the handset application. If the device is lost, all the locally cached data is completely unreadable. The symmetric key that encrypted this data is also unreadable.
The passphrase is the weakest link in the chain. If the user enters an overly simple password, access could be gained to the private key and hence the locally cached data. That being said, it would be possible to further extend this architecture to store the encrypted symmetric key on the server.
This way, even if the passphrase of the private key is compromised, the locally cached data still cannot be accessed. This is because the encrypted strong symmetric cipher key is 14 By the time the passphrase has been cracked, there has been ample time to report the stolen phone and revoke this key from this user account on the server.
Furthermore, under this scheme, the key stored on the server is still encrypted. It is also possible to enforce a strong password policy directly from the handset application. Even if this design is significantly more secure than the previous iteration, to the user, the experience is the same. The user must enter a username and password to prove his identify. We could augment the architecture in yet another direction. Such a design would prevent terminated employees, i.
Chapter 6 6. Figure 5 Android Execution Environment 17 Figures 4 and 5 represent the regular Java and Android execution paths respectively. It is interesting to note here however is that the Android compilers do not operate on Java language code. Instead, the Android translators work on the resulting Java bytecode emitted from a traditional Java compiler.
As such, it is possible to reuse existing Java libraries, even if the original source code is not available. Such libraries must meet stringent requirements however, they need to: 1. Special care will be needed in the integration phase of such code but the potential savings offered by such integration far outweighs the cost of rewriting well-coded, well-documented and well-tested libraries ready for use. Furthermore, it is expected that has Apache Harmony matures, more and more compatibility issues will be resolved further increasing the pool of available Java code that will be able to execute unmodified under the Android platform.
Notably, Dalvik does not make use of just in time JIT Compilation to improve the performance of an application at runtime. Furthermore, Dalvik is not a Java virtual machine. Google claims this format allows battery power to be better-conserved at all different stages of execution of an application.
This means that standard Java SE applications and libraries cannot be used directly on the Android Dalvik virtual machine. Dalvik however stands at the center of the Android value proposition. Its low electrical power consumption, rich libraries, and unified, non-fragmented application programming interfaces make it stand out, or so Google hopes, over the fragmented ecosystem that is Java ME35 today.
Furthermore, since Dalvik uses the Java programming language but not the Java execution environment JVM , Google is free to develop Android without the need to license or obtain certification from Sun Microsystems Inc, the legal owner of the Java trademark and brands.
Chapter 7 7. This process is created for the application when some of its code needs to be run, and will remain running until it is no longer needed and the system needs to reclaim its memory for use by other applications. An important and unusual feature of Android is that an application process's lifetime is not directly controlled by the application itself. Instead, it is determined by the system through a combination of the parts of the application that the system knows are running, how important these things are to the user, and how much overall memory is available in the system.
It is important that application developers understand how different application components in particular Activity, Service, and IntentReceiver impact the lifetime of the application's process. Not using these components correctly can result in the system killing the application's process while it is doing important work. A common example of a process life-cycle bug is an IntentReceiver that starts a thread when it receives an Intent in its onReceiveIntent method, and then returns from the function.
Once it returns, the system considers that IntentReceiver to be no longer active, and thus its hosting process no longer needed unless other application components are active in it. Thus, it may kill the process at any time to reclaim memory, terminating the spawned thread that is running in it.
The solution to this problem is to start a Service from the IntentReceiver, so the system knows that there is still active work being done in the process. To determine which processes should be killed when low on memory, Android places them into an "importance hierarchy" based on the components running in them and the state of those components. These are, in order of importance: 1. A foreground process is one holding an Activity at the top of the screen that the user is interacting with its onResume method has been called or an IntentReceiver that is currently running its onReceiveIntent method is executing.
There will only ever be a few such processes in the system, and these will only be killed as a last resort if memory is so low that not even these processes can continue to run. Generally at this point the device has reached a memory paging state, so this action is required in order to keep the user interface responsive. A visible process is one holding an Activity that is visible to the user on-screen but not in the foreground its onPause method has been called.
This may occur, for example, if the foreground activity has been displayed with a dialog appearance that allows the previous activity to be seen behind it. When the activity resumes, you can reacquire the necessary resources and resume actions that were interrupted. These state transitions are all part of the activity lifecycle. Another application component can start a service, and it continues to run in the background even if the user switches to another application.
Additionally, a component can bind to a service to interact with it and even perform inter process communication IPC. These are the three different types of services: 1. You can use the JobScheduler by registering jobs and specifying their requirements for network and The system then gracefully schedules the jobs for execution at the appropriate times.
The JobScheduler provides many methods to define service-execution conditions. Started A service is started when an application component such as an activity calls startService. After it's started, a service can run in the background indefinitely, even if the component that started it is destroyed. Usually, a started service performs a single operation and does not return a result to the caller.
For example, it can download or upload a file over the network. When the operation is complete, the service should stop itself. Bound A service is bound when an application component binds to it by calling bindService. A bound service offers a client-server interface that allows components to interact with the service, send requests, receive results, and even do so across processes with inter process communication IPC. A bound service runs only as long as another application component is bound to it.
Multiple components can bind to the service at once, but when all of them unbind, the service is destroyed. You can store the data in the file system, an SQLite database, on the web, or any other persistent storage location your application can access.
A content provider provides a structured interface to application data. Via a content provider your application can share data with other applications. Android contains an SQLite database which is frequently used in conjunction with a content provider. These messages are sometime called events or intents. For example, applications can also initiate broadcasts to let other applications know that some data has been downloaded to the device and is available for them to use, so this is broadcast receiver who will intercept this communication and will initiate appropriate action.
An application can call a component directly explicit Intent or ask the Android system to evaluate registered components based on the intent data implicit intents. For example the application could implement sharing of data via an intent and all components which allow sharing of data would be available for the user to select.
Applications register themselves to an intent via an intent. Filter Intents allow an Android application to start and to interact with components from other Android applications. Or you can bind to the service by passing an Intent to bindService.
Android Studio is freely available under the apache license. Android Studio is designed specifically for Android development.
All the required tools to develop Android applications are open source and can be downloaded from the Web. Following is the list of softwares that is needed before starting Android application programming. Android UI Design 5. They are used less often than some other layouts, simply because they are generally used to display only one view, or views which overlap.
The efficiency of a frame layout makes it a good choice for screens containing few view controls home screens, game screens with a single canvas, and the like. Sometimes other inefficient layout designs can be reduced to a frame layout design that is more efficient, while other times a more specialized layout type is appropriate.
Frame layouts are the normal layout of choice when you want to overlap views. Linear Layout Linear layouts are one of the simplest and most common types of layouts used by Android developers to organize controls within their user interfaces.
The linear layout works much as its name implies: it organizes controls linearly in either a vertical or horizontal fashion. Relative Layout The relative layout works much as its name implies: it organizes controls relative to one another, or to the parent control itself. It means that child controls, such as ImageView, TextView, and Button controls, can be placed above, below, to the left or right, of one another.
Child controls can also be placed in relation to the parent the relative layout container ; including placement of controls aligned to the top, bottom, left or right edges of the layout.
Table Layout A table layout is exactly what you might expect: a grid of made up of rows and columns, where a cell can display a view control. From a user interface design perspective, a TableLayout is comprised of TableRow controls—one for each row in your table.
However, for data that is already in a format suitable for a table, such as spreadsheet data, table layout may be a reasonable choice.
On Android 3. Beginning with Android 3. Context Menu and Contextual Action Mode A context menu is a floating menu that appears when the user performs a long-click on an element.
It provides actions that affect the selected content or context frame. A contextual menu offers actions that affect a specific item You can provide a context menu for any view, but they are most often used for items in a ListView, GridView, or other view collections in which the user can perform direct actions on each item.
Popup Menu A popup menu displays a list of items in a vertical list that's anchored to the view that invoked the menu. It's good for providing an overflow of actions that relate to specific content or to provide options for a second part of a command.
A dialog does not fill the screen and is normally used for modal events that require users to take an action before they can proceed. It only fills the amount of space required for the message and the current activity remains visible and interactive. Accredited Curriculum. Learn from the Experts. Professional Certificate. Guranteed Career Growth. Placement Assistance. Earn a Valuable Certificate. It is dependent on Linux kernel for the functions like threading and low-level memory guidance.
Also See: Optical Coherence Tomography ppt. Android is upgrading day by day by including the new features in it and also making the lives more comfortable. Some of the recent versions of android are as follows:. In these days all the tasks that were performed in a computer can now be performed on the mobile and this means that you the more virtual information or data in the mobile phones and need to secure it efficiently. Some of the features of the android security are:.
Android is now the best operating system for the mobile phones and this not only provides the security features but also enabled us to know about emails, web and much more. Also See: Google Wave ppt. The trends that are going to rule the Android world are mentioned below:. This technology is going to optimize the searching based on the location through Bluetooth signals.
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