To facilitate access to the side menu, all screens that correspond to entries in this menu should contain a side menu indicator next to the application icon in the Action Bar. Clicking on the application icon causes the menu to exit from the left edge of the screen.
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All screens below the hierarchy should include a regular "up" indicator next to the application icon. The side menu is still available on the swipe from the left edge, but this is not displayed in the Action Bar.
If we launch Evernote, then we will see the “Up” icon on the main screen. Clicking on it will bring up the side menu. On the other screens, including the list of entries in notepad and even the screen for viewing the entry, the up icon is also drawn and it also opens the side menu, and not navigating through the hierarchy of screens!Pressing the back button on top-level screens never brings up the side menu! Instead, the back button behaves according to the transition rules for top-level screens, such as moving to the previous application up the stack or to the home screen.

When the side menu is open, the user can close it in one of the following ways:
- Pushing content outside the menu
- Swipe right to left
- By clicking on the application icon / title in the Action Bar
- By pressing the back button
Sometimes, a context action bar (CAB) can be displayed to the user instead of the standard one. This usually happens when the user selects text or several items after a “push-and-hold” gesture. While the CAB is visible, the user still needs to allow the side menu to be called from the edge of the screen. When the menu is open, the CAB must be replaced with the action bar menu. When the user closes the side menu, the context action bar becomes visible again.

Android phones with traditional hardware buttons do not show a virtual navigation bar at the bottom of the screen. Instead, the overflow menu of the Action Bar is available for a call by pressing the hardware “menu” button. As a result, the same action menu pops up, like when you click on the overflow icon of the action bar, but at the bottom of the screen.


A long press on the action icon leads to the appearance of her name.


Context Action Bar (CAB), this is a temporary panel that closes a normal Action Bar application for the duration of the subtask. CABs are usually used to perform operations on selected data or text.

In previous versions of Android, a long press was usually used to open the context menu.
This behavior has changed in Android 3.0. A long press is now used for highlighting, combining the selection control function and contextual actions in a new element called the context action bar.
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- Reserve a long press for selection only. Do not use it for traditional context menus.
- If your application does not support multiple selection in the list, a long press should not do anything.
Source: https://habr.com/ru/post/215027/
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