![]() ![]()
(since it is invisible) for a flatter and more efficient layout hierarchy. Useless leaf - A layout that has no children or no background can often be removed.Padding etc, it can be replaced with a merge tag which is slightly more efficient. ImageView and a TextView can be more efficiently handled as a compound drawable.įrameLayout is the root of a layout and does not provide background or Use compound drawables - A LinearLayout which contains an.The Layoutopt tool and has much greater functionality. ![]() Tool on your layout files to search for possible view hierarchy optimizations. It is always good practice to run the lint #Automatically roll down the listview android studio how to#More information about double taxation and how to prevent it, see This phenomenon is called double taxation. In some complex layouts, the system may waste effort measuring the same UIĮlement more than once. It is just oneĮxample of how each layout has appropriate uses and you should carefully consider whether using LinearLayout design, which can slow down the speed of measurement. Most of the difference is due to the use of layout_weight in the The benefits, as small as they might seem, are multiplied several times because this Layout hierarchy for the layout in figure 1, RelativeLayout, you can see that the layout becomes a two-level hierarchy. The layout shallow and wide, rather than narrow and deep. The performance might improve by flattening the layout-make Revise your layoutīecause the layout performance above slows down due to a nested LinearLayout, For example, figure 2 shows the layout for theįigure 2. The layout hierarchy of the selected component. #Automatically roll down the listview android studio windows#Choose yourĬomponent from the Windows tab, and click Hierarchy View to view Hierarchy Viewer shows a list of availableĭevices and their running components. Conceptual layout for an item in a ListView. Times-such as this one-are optimized as the performanceįigure 1. It is especially important that layouts that will be inflated multiple ![]() This layout shows a small bitmap image on the left and two stacked items Layout and Draw performance, helping you identify potential issues.įor example, figure 1 shows a layout that's used as an item in a ListView. The traffic lights on each block represent its Measure, Hierarchy Viewer works by allowing you to select running processes on a connected device orĮmulator, then display the layout tree. You to analyze your layout while your application is running. The Android SDK tools include a tool called Hierarchy Viewer that allows In this lesson you'll learn to use Hierarchy Viewer and Lint to examine and optimize your Is inflated repeatedly, such as when used in a ListView or GridView. This is particularly important when the layout LinearLayout that use the layout_weight parameter can be especiallyĮxpensive as each child needs to be measured twice. Furthermore, nesting several instances of Lead to an excessively deep view hierarchy. For example, using nested instances of LinearLayout can However, each widget and layout you add to your application requires initialization, First, specify an id for the ListView, and then set the width Both the height and the height are set to match_parent, so the Android Listview occupies the entire layout space.It is a common misconception that using the basic layout structures leads to the most efficient #Automatically roll down the listview android studio code#Then modify The code in activity_main.xml is as follows: Īdding the Android Listview control to the layout is quite simple. However, compared to the several controls introduced earlier, the usage of Android Listview is relatively more complicated, so we will use it separately Use one section to explain the Android Listview in great detail.įirst, create a new ListViewTest project, and let ADT automatically help us create a good activity. I believe you are actually using this control every day, such as viewing the mobile contact list, flipping through the latest news on Weibo, and so on. Android Listview allows users to Refers to the way of sliding up and down to scroll the data outside the screen to the screen, while the original data on the screen will scroll out of the screen. When there is a large amount of data to be displayed in the sequence, you can use Android Listview to achieve it. Since the screen space of mobile phones is relatively limited, there is not much content that can be displayed on the screen at one time. Improve the efficiency of Android Listview:Īndroid ListView can definitely be called one of the most commonly used controls in Android, and almost all applications will use it. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |