Android 中的滚动视图
在安卓中，ScrollView 是一个视图组，用于制作可垂直滚动的视图。滚动视图只包含一个直接子视图。为了在滚动视图中放置多个视图，需要将一个视图组(如线性布局)作为直接子视图，然后我们可以在其中定义多个视图。滚动视图仅支持垂直滚动，因此为了创建水平滚动视图，使用了水平滚动视图。
滚动视图的 XML 属性
继承属性:
从框架布局
从视图
来自视图组
方法
这个例子演示了使用 Kotlin 在安卓系统中创建一个 ScrollView 的步骤。
第一步:创建新项目
- 单击文件，然后单击新建= >新建项目。
- 为项目模板选择“空活动”。
- 选择语言作为 Kotlin。
- 根据您的需要选择最小的软件开发工具包。
第二步:修改字符串. xml
在 strings.xml 文件中添加一些字符串，在应用程序中显示这些字符串。
kt
<resources>
<string name="app_name">gfgapp_scrollview</string>
<string name="scrolltext">Kotlin is a statically typed,
general-purpose programming language developed
by JetBrains, that has built world-class IDEs
like IntelliJ IDEA, PhpStorm, Appcode, etc.
It was first introduced by JetBrains in 2011
and a new language for the JVM. Kotlin is
object-oriented language, and a “better language”
than Java, but still be fully interoperable
with Java code. Kotlin is sponsored by Google,
announced as one of the official languages for
Android Development in 2017\.
Advantages of Kotlin language:
Easy to learn – Basic is almost similar to java.
If anybody worked in java then easily understand
in no time. Kotlin is multi-platform – Kotlin is
supported by all IDEs of java so you can write
your program and execute them on any machine
which supports JVM. It’s much safer than Java.
It allows using the Java frameworks and libraries
in your new Kotlin projects by using advanced
frameworks without any need to change the whole
project in Java. Kotlin programming language,
including the compiler, libraries and all the
tooling is completely free and open source and
available on github. Here is the link for
Github https://github.com/JetBrains/kotlin
Applications of Kotlin language:
You can use Kotlin to build Android Application.
Kotlin can also compile to JavaScript, and making
it available for the frontend. It is also designed
to work well for web development and server-side
development.Kotlin is a statically typed, general-purpose
programming language developed by JetBrains that
has built world-class IDEs like IntelliJ IDEA,
PhpStorm, Appcode, etc. It was first introduced
by JetBrains in 2011.Kotlin is object-oriented
language and a better language than Java, but still
be fully interoperable with Java code. A constructor
is a special member function that is invoked when
an object of the class is created primarily to initialize
variables or properties. A class needs to have a constructor
and if we do not declare a constructor, then the compiler
generates a default constructor.
Kotlin has two types of constructors –
Primary Constructor
Secondary Constructor
A class in Kotlin can have at most one primary
constructor, and one or more secondary constructors.
The primary constructor
initializes the class, while the secondary
constructor is used
to initialize the class and introduce some extra logic.
Explanation:
When we create the object add for the class then
the values 5 and 6
passes to the constructor. The constructor
parameters a and b
initialize with the parameters 5 and 6 respectively.
The local variable c contains the sum of variables.
In the main, we access the property of
constructor using ${add.c}.
Explanation:
Here, we have initialized the constructor
parameters with some
default values emp_id = 100 and emp_name = “abc”.
When the object emp is created we passed the values for
both the parameters so it prints those values.
But, at the time of object emp2 creation,
we have not passed
the emp_name so initializer block uses
the default values and
print to the standard output.</string>
</resources>
