Android button with shadow

Mastering Shadows in Android

Jan 9, 2018 · 6 min read

If we want to create better apps, I believe that we need to follow material design guideline.In general terms, Material design is a three-dimensional environment containing light, material, and cast shadows. Light and Shadow are important for us if we want to follow material design guideline in our application development process.

I will try to explain following topics in this article.

• 3D in Android
• Depth
• Z value, elevation and Translation Z
• Light
• Button state (Pressed and Resting)
• Outline
• Custom Outline with ViewOutlineProvider

Before deep dive into shadow and light, I want to show you what our environment is.

What is 3D?

The material environmen t is a 3D space, which means all objects have x, y, and z dimensions. The z-axis is perpendicularly aligned to the plane of the display, with the positive z-axis extending towards the viewer. In Material Design world, every object has 1 dp thickness.

What is Depth in Android?

Material design differs from other design guides because It has depth. We can say that depth defines view’s importance level in user interface. We can think there is a paper layer in our desk. If we put another paper on it, our eyes will perceive that it has a depth.

Let’s imagine it with an app screenshot from the material design guideline.

Let’s see our elements in the screen.

• Screen (Surface layer — 0 depth)
• Cardviews
• Appbar Layout
• Floating Action Button

Every element has a priority to another. Cardviews can scroll in its recyclerview. So we can say that our first layer is scrollable content. The second layer is appbar layout. The third layer (Top layer) is the floating action button.

So how do we define the order? How do we make the user feel the depth? Answer: Z- value.

What is Z-value in Android?

The Z value for a view has two components:

• Elevation: The static component.
• Translation Z: The dynamic component used for animations.

I always wonder that what is the difference between elevation and translation.

Elevation is static. So you don’t change it dynamically. If you want to animate your view in Z-axis (like pressing and resting) you need to use translation-Z attribute.

Translation Z is dynamic. In your empty project, If you create a button and press it, you will see that shadow gets bigger with an animation. Actually, elevation value is not changing. Translation Z property is changing. Android is using default state list animator changes translation Z property of the view.

Z-Value = Elevation + TranslationZ

What if we change the value of Z of two views that intersect. Does Android handle the order on the screen? Yes. Let me show you that with a diagram that I designed.

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Android button with shadow

September 06, 2017

One of the important UI components in applications is Button. Button can be used to provide actions for user to perform and attach user events to back end behavior.

This post gives details about using and styling android button with examples.

Adding Button to Layout

Android user interface is defined in layout xml file. You can add Button element and set attributes to xml manually. Or using android studio layout design tool, you can add button component from palette to layout and set attributes.

Button Attributes

Button is a subclass of TextView and inherits attributes from TextView and View classes. Below are some of the important button attributes which can be used to defined desired button look and behavior.

• background : to set background to either color or a drwable.
• onClick : to set method that needs to be run when a button is clicked.
• minHeight : to define minimum height of button
• minWidth : to define minimum width of button.
• stateListAnimator : to define animation when button state changes.
• focusable : to indicate whether keystroke should work
• clickable : to indicate whether button is clickable or not
• gravity : to set button text alignment.
• textAppearance : to set text style.

Enabling and disabling Button

You can use enabled attribute to enable and disable button by setting it to true or false. A button can be enabled or disabled in program by calling setEnabled method as shown below.

Button Drawable

You can make button display image and text using drawableTop, drawableBottom, drawableRight, and drawableLeft attributes below screen shot shows output of setting them.

Android Image Button

Android provides ImageButton which can be used to make an image as button. To set an image, you can use src attribute of ImageButton. You can even use different images to be shown in different button states by defining xml drawable selector as shown below.

Xml drawable selector example

Handling Button Clicks

Button clicks can be handled in two ways. First one is by setting onClick attribute of Button in layout xml. Second one is by assigning on click listener to button in activity or fragment.

To set onClick attribute, first define a public void method with View as argument in activity or fragment and use the method name as value to set onClick attribute as shown below.

Below code shows handling button clicks using on click listener.

Android Button Design and Styles

You can apply styles and themes to change look and feel of buttons. Android platform provides pre-defined material styles. Read material styles and compatibility post to learn about android material styles. Below screen shot shows buttons styled with different material styles.

Applying theme or style to button.

Button Styles Customization

You can change the default colors of material styles applied to button by setting colorAccent attribute at application level and colorButtonNormal attribute at widget level to the desired colors. Attribute colorControlHighlight is used to set color for button when it is in pressed state.

Once you define custom style, you can apply it to buttons using theme attribute. Below is an example of custom theme.

Rounded Corner Button

You can define inset as shown below to create rounded corner button and save the drwable xml in res/drawable folder. You can increase or decrease corners element’s radius attribute to adjust button corner radius.

Then define style setting the background attribute to the xml drawable and apply it to button using style attribute.

Button Elevation and Shadow

You can set elevation and translationZ attributes to draw shadow of button.

Button Shadow Animation Customization

You can define different shadow properties for different states of button and animate the transition by defining selector. You can apply the animator to button using stateListAnimator property.

Notice that stateListAnimator set to null in the above (elevation and translationZ) example. This was done to remove default animator applied using stateListAnimator attribute in material themes for button. In order for elevation and translationZ to work, stateListAnimator needs to be set to null.

To customize the animation, meaning animating shadow transition between button states, you need to define selector as shown below in res/animator folder and set stateListAnimator property of custom theme to the defined animator.

Below is an example of state animator.

Apply the below custom theme, which is using state animator, to a button using style or theme attribute.

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Android app development tutorials and web app development tutorials with programming examples and code samples.

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Как создать тень для кнопки

Как вы можете видеть на картинке, я хочу, чтобы тень за Button . Я создал Button с закругленными углами. Но проблема в том, что я не могу создать тень за этой Button . Как я могу это достичь?

Используйте этот подход, чтобы получить желаемый вид.
Button_selector.xml:

И в вашем XML-макете:

Для Android версии 5.0 и выше

Попробуйте Elevation для других видов.

Ниже версии 5.0,

Для всех просмотров,

Если вы нацеливаете устройства до Lollipop, вы можете использовать Shadow-Layout , так как это легко, и вы можете использовать его в разных типах макетов.

Добавьте теневой макет в файл Gradle :

В верхней части xml-макета, где у вас есть кнопка, добавьте вверху :

Он предоставит пользовательские атрибуты.

Затем вы помещаете вокруг себя макет тени. Button :

Затем вы можете настроить параметры app: в соответствии с вашей теневой тенью.

Здесь моя кнопка с тэгом «cw_button_shadow.xml» под возможностью рисования

Моя кнопка xml, размер вашей высоты и веса

Я пробовал код сверху и сделал свою собственную тень, которая немного ближе к тому, чего я пытаюсь достичь. Может быть, это тоже поможет другим.

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arvkmr / Round_white_button_drop_shadow.xml

This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters

xml version = » 1.0 » encoding = » utf-8 » ?>

selector xmlns : android = » http://schemas.android.com/apk/res/android » >

item >

layer-list >

item >

shape android : shape = » oval » >

gradient

android : startColor = » #FF000000 «

android : endColor = » #00000000 «

android : gradientRadius = » 31dp «

android : type = » radial «

/>

shape >

item >

item android : top = » 4dp » android : left = » 4dp » android : right = » 4dp » android : bottom = » 4dp » >

shape android : shape = » oval » >

size android : width = » 55dp «

android : height = » 55dp »/>

solid android : color = » @android:color/white »/>

shape >

item >

layer-list >

item >

selector >

You can’t perform that action at this time.

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Теневые тени ImageButton на Android

Эта платформа для Android используется для включения тени на ImageButton . Он используется в XAML путем установки ImageButton.IsShadowEnabled Свойства BIND в true , а также ряда дополнительных необязательных свойств, которые могут быть привязаны для управления тенью.

Кроме того, его можно использовать в C# с помощью API-интерфейса Fluent:

Тень рисуется как часть ImageButton фона, а фон рисуется только в том случае, если BackgroundColor свойство задано. Таким образом, тень не будет отображаться, если ImageButton.BackgroundColor свойство не задано.

ImageButton.On Метод указывает, что эта платформа будет запускаться только в Android. ImageButton.SetIsShadowEnabled Метод в Xamarin.Forms.PlatformConfiguration.AndroidSpecific пространстве имен используется для управления включением тени на ImageButton . Кроме того, можно вызвать следующие методы для управления тенью тени:

• SetShadowColor — Задает цвет тени. Цвет по умолчанию — Color.Default .
• SetShadowOffset — Задает смещение тени. Смещение изменяет направление, в котором происходит приведение тени, и указывается как Size значение. Size Значения структуры выражаются в единицах, не зависящих от устройства, где первое значение равно расстоянию слева (отрицательное значение) или правому (положительное значение), а второе значение равно расстоянию выше (отрицательное значение) или ниже (положительное значение). Значение этого свойства по умолчанию равно (0,0, 0,0), что приводит к приведению тени вокруг каждой стороны ImageButton .
• SetShadowRadius — задает радиус размытия, используемый для визуализации тени. Значение радиуса по умолчанию — 10,0.

Состояние тени можно запрашивать путем вызова GetIsShadowEnabled GetShadowColor методов,, GetShadowOffset и GetShadowRadius .

В результате тень может быть включена в ImageButton :

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