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This article focuses on "how to design a user interface in Android". Friends who are interested may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to design a user interface in Android.

Activity is a basic component of the user interface of Android applications. But Activity itself does not provide a user interface (User Interface). From the program structure level, an Android application is an instance of class android.app.Application, and Application can contain multiple android.app.Activity instances. Each Activity comes with a Window class, which does not provide much functionality on the Android platform and can be used mainly to control the title bar (top of the screen). For example, you can use the following code to set UI full screen display:

RequestWindowFeature (Window.FEATURE_NO_TITLE); indow (). SetFlags (WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN)

Activty has no user interface by default, and if you need to display the user interface, you can call setContentView () to set the ContentView of Activity. ConentView describes specific UI components, such as text boxes, tags, list boxes, and picture boxes.

The user interface of Android actually refers to the design of ContentView. "View" is misleading at first, and "View" on other platforms generally refers to a concept similar to Form. On the Android platform, View is a UI component, which is equivalent to the Component,ViewGroup of other platforms and the Container of other platforms, as shown below:

With this correspondence, it is easy to apply your existing user interface design knowledge to Android user interface design.

In addition, a recommended method for Android user interface design is to use XML to describe UI, which is not the initiative of the Android platform. Java ME Polish,WPF,Silverlight and others all use XML to describe UI. The advantage of using XML to describe is to separate the user interface from the program logic, so that the change of the user interface does not affect the program logic, and the change of the program logic does not affect the user interface. In fact, it adopts the design of MVC mode. Activity is the ContentView of Controller,Activity in MVC and the View of MVC. If you don't want to use XML to describe UI, you can also use code to create UI, but this approach is cumbersome and increases the coupling between modules.

After understanding the View and ViewGroup of Android, the specific design of the user interface is not complicated. Generally speaking, ViewGroup defines the layout Layout of its sub-View, that is, the placement of other View (text boxes, labels and other controls or other ViewGroup) in the user interface. As shown in the figure above, this hierarchical relationship can be nested. Through nesting, you can define any user interface.

The basic layout in Android is as follows:

FrameLayout

The simplest layout object

Deliberately leave blank space on the screen, you can then fill in a separate object

For example: a picture you want to change

All child elements are nailed to the upper left corner of the screen

Cannot specify a location for a child element

LinearLayout

Align all child elements in one direction (vertical or horizontal)

All the child elements are stacked one by one

A vertical list will have only one child element per row (no matter how wide they are)

A horizontal list is just the height of a column (filled by the height of child elements)

TableLayout

Put child elements in rows and columns

Do not display rows, columns, or cell boundaries

Cells cannot span rows, as in HTML

AbsoluteLayout

Enables the child element to indicate the exact X / Y coordinates to be displayed on the screen

(0pc0) is the upper left corner

When you move down or right, the coordinate values increase.

Allow elements to overlap (but not recommended)

Note:

It is generally recommended not to use AbsoluteLayout unless you have a good reason to use it

Because it's quite strict and doesn't work well in different device displays.

RelativeLayout

Let child elements specify their position relative to other elements (specified through ID) or relative to the parent layout object

At this point, I believe you have a deeper understanding of "how to design the user interface in Android". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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