By following just a few simple principles, says Jason Ostrander, author of Android UI Fundamentals.Seven Tips for Proper Navigation in Android Apps Seven Tips for Proper Navigation in Android Apps.By following just a few simple principles, says Jason Ostrander, author of Android UI Fundamentals Develop Design, Android developers can minimize user frustration with navigation in their apps.From the author of Android development has exploded in recent years, making Android the largest smartphone OS by market share.Netflix is the leading subscription service for watching TV episodes and movies.As its user base increases, so do the number and quality of apps in the Google Play store.However, one area where developers still seem to struggle is with Androids navigation model.Screenshot-from-2017-05-03-15_10_20.png' alt='Android Notification Resume Last Activity Gmail' title='Android Notification Resume Last Activity Gmail' />Many apps fail to handle the nuances of activities and tasks properly, forcing users to endure endless back pressing to exit an app.To address this issue, this article presents seven tips for proper implementation of navigation in your Android app.Learn from the Android Documentation.For many years, the Android documentation on navigation has been lacking.Luckily, Google has recently addressed this problem, and now there are many resources explaining how to navigate an Android app.In particular, the design guidelines and navigation training article provide clear case studies, working through the high level application use case and following through with individual screens and the actions of the back and up buttons.You should read both of these resources and think carefully about your own application and how you expect people to use it.In addition, you should understand the basics of tasks and the back stack to leverage Android effectively.Learn the Difference Between Up and Back.Android version 3.Action. Bar. This bar sits at the top of the screen and contains common actions and navigation elements, such as tabs.It also includes an icon on the left side that can be used as an up button see Figure 1.Figure 1 The up button as displayed in the Google Play app.Its important to understand the differences between the up and the back button.First, the up button is only relevant within your app.It will never take the user to a different application.In addition, the concept of up means that the user will return to a logical parent of the current activity.In the Gmail app, for example, pressing the up button while viewing an email message would take you to a list of email messages.If no parent exists, up should take the user to the home activity of your app.The back button, on the other hand, moves back through the stack of recent activities.This is limited to those activities in the current task more about that in a moment.Think of it like the browsers back button.As a user navigates through an app and into others, the back button will take him backward through those activities, until he reaches the launcher.Once the user reaches the launcher, he can no longer press back.Understand How Tasks Relate to the Back Stack.Tasks are collections of activities opened in chronological order by the user.A new task is created when the user opens an application from the launcher.Moving from one application to another generally doesnt start a new task.Instead, the new activity becomes part of the existing task.For example, if you navigate from an existing app to the Google Maps app, the displayed map will be part of the existing app task.Pressing back from the map will take the user back to the original app.Each Android task has an associated back stack.The back stack can seem complicated at first, but its implementation is firmly rooted in basic computer science.Its just a stack.The elements in the stack are the screens of an app, called activities.As you navigate from one activity to another, the previous activity is pushed onto the stack.When you press the back button, the current activity the current screen displayed to the user is destroyed, and the activity at the top of the back stack is popped off and displayed to the user.If the back stack is empty, the user is taken back to the launcher.An important point to note is that the system will not keep tasks around forever.When it needs resources, it will often clear the task and corresponding back stack.This is quite common, and you shouldnt rely on any particular back stack state to exist for your app to function correctly.If you really need it, however, its possible to disable this behavior by setting the always.Retain. Task. State attribute on an activity in your manifest.Define the Proper Activity Attributes.By default, new activities are launched into existing tasks.This can be changed by setting activity attributes in your application manifest.For example, setting the launch.Mode attribute to single.Task ensures that only a single instance of an activity will be created lt activity android name.Test. Activity. android launch.Modesingle. Task.Now, intents for Test.Activity will resume any task that already contains Test.Activity, rather than creating another instance.If no instance exists, the system creates a new task containing Test.Activity as normal.Another useful activity attribute is task.Affinity. You can use task.Affinity to assign an activity to a particular task.By default, all activities in your application have the same affinity.Using the task. Affinity attribute, you can group them into separate tasks or even assign them to tasks in other applications.Here, the Test. Activity is assigned to a specific task lt activity android name.Test. Activity. android task.Affinitycom. example.Second. Task. Read the Android documentation for a full explanation of the activity attributes available for controlling tasks.Use Intent Flags.Activity attributes work well when you always want the same behavior for an activity.But sometimes you need control over a specific activity launch.For those cases, use Intent flags.Intents are used to launch activities on Android.You can set flags that control the task that will contain the activity.Flags exist to create a new activity, use an existing activity, or bring an existing instance of an activity to the front.For example, its common to launch an activity when the user taps a notification.Often, apps will use the default intent flags, resulting in multiple copies of the same activity in the back stack.This forces the user to press back repeatedly while each instance of the activity is popped off the back stack.To fix this problem, set the flags Intent.FLAGACTIVITYNEWTASK and Intent.FLAGACTIVITYCLEARTASK to switch to an existing instance of the activity and clear any other activities on top of it Intent intent new Intentcontext, Test.Activity. class. FlagsIntent.FLAGACTIVITYCLEARTASK Intent.FLAGACTIVITYNEWTASK.Activityintent Note that in Android API version 1.Intent class includes new static methods that create intents with the proper flags already set.Look here for an example.Use the New Compatibility Package Classes.Googles recent update to the compatibility package added two new utility classes to aid with app navigation.The first of these utilities is called Nav.Utils. It provides static methods for navigating up to the parent of the current activity, as declared in your application manifest.Here is an example manifest entry lt activity android name.Test. Activity. PARENTACTIVITY.Test. Parent. Activity.Test. Parent. Activity is declared as a parent of Test. How To Crack Md5 Ubuntu Desktop on this page. Activity using a metadata element.Now, in the Test.Activity class, Nav.Utils is used to navigate up to Test.Parent. Activity when the user presses the up button Override.Options. Item. Selectedandroid.Menu. Item item. Item.Id android. R. id.Nav. Utils. navigate.Up. From. Same. Taskthis.Options. Item. Selecteditem.The up button uses the same resource identifier as the Action.Bar home icon, android.R. id. home. In addition to navigation, the Nav.Utils class provides a Boolean method specifying whether the current activity should display an up button.The second class is Task.Stack. Builder. This class can be used to construct a complete back stack, with a root activity and several activities on top of it.This back stack is created with a stack of intents.Calling start. Activities will create the back stack using the intents to create each activity and pushing it onto the stack.Task. Stack. Builder tsb Task.Stack. Builder. fromthis.Parent. Stackthis.Next. Intentnew Intentthis, Test.Activity. class. Next.Intentnew Intentthis, Test.Activity. class. Next.Intentnew Intentthis, Test.
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