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📜  Android-UI控件

📅  最后修改于: 2021-01-05 04:55:32             🧑  作者: Mango

输入控件是应用程序用户界面中的交互式组件。 Android提供了可在UI中使用的多种控件，例如按钮，文本字段，搜索栏，复选框，缩放按钮，切换按钮等等。

UI控件

UI元素

View是一个对象，它在屏幕上绘制一些用户可以与之交互的对象，而ViewGroup是一个对象，该对象包含其他View(和ViewGroup)对象，以便定义用户界面的布局。

您可以在XML文件中定义布局，该XML文件提供类似于HTML的易于阅读的结构。例如，带有文本视图和按钮的简单垂直布局如下所示：

Android UI控件

Android提供了许多UI控件，可让您为应用构建图形用户界面。

Sr.No. UI Control & Description
1 TextView

This control is used to display text to the user.
2 EditText

EditText is a predefined subclass of TextView that includes rich editing capabilities.
3 AutoCompleteTextView

The AutoCompleteTextView is a view that is similar to EditText, except that it shows a list of completion suggestions automatically while the user is typing.
4 Button

A push-button that can be pressed, or clicked, by the user to perform an action.
5 ImageButton

An ImageButton is an AbsoluteLayout which enables you to specify the exact location of its children. This shows a button with an image (instead of text) that can be pressed or clicked by the user.
6 CheckBox

An on/off switch that can be toggled by the user. You should use check box when presenting users with a group of selectable options that are not mutually exclusive.
7 ToggleButton

An on/off button with a light indicator.
8 RadioButton

The RadioButton has two states: either checked or unchecked.
9 RadioGroup

A RadioGroup is used to group together one or more RadioButtons.
10 ProgressBar

The ProgressBar view provides visual feedback about some ongoing tasks, such as when you are performing a task in the background.
11 Spinner

A drop-down list that allows users to select one value from a set.
12 TimePicker

The TimePicker view enables users to select a time of the day, in either 24-hour mode or AM/PM mode.
13 DatePicker

The DatePicker view enables users to select a date of the day.

创建UI控件

输入控件是应用程序用户界面中的交互式组件。 Android提供了可在UI中使用的多种控件，例如按钮，文本字段，搜索栏，复选框，缩放按钮，切换按钮等等。

如上一章所述，视图对象可能具有唯一的ID，该ID将在树中唯一地标识视图。 XML标记内的ID的语法是-

android:id="@+id/text_id"

要创建UI控件/视图/小部件，您将必须在布局文件中定义视图/小部件，并为其分配唯一的ID，如下所示：

然后最终创建Control对象的实例并从布局中捕获它，请使用以下命令-

TextView myText = (TextView) findViewById(R.id.text_id);