Buttons, Image Views, and Image Buttons

1. One button control

1. Inheritance diagram

• Button is a subclass of TextView

2. Common attributes

Attributes	meaning
text	text content
textSize	Text font size, unit: sp
textColor	Text color, #ff0000 - red
background	Background color or background image
layout_height	Height, unit: dp (wrap_content, match_parent)
layout_weight	Width, unit: dp (wrap_content, match_parent)
onClick	Click event (used to bind event handling methods)

2. Image view

1. Inheritance diagram

• ImageView is a subclass of View

2. Common attributes

Attributes	meaning
layout_height	Height, unit: dp (wrap_content, match_parent)
layout_weight	Width, unit: dp (wrap_content, match_parent)
src	Source (used to set the image source)
background	Background (used to set the background image)
scaleType	Scaling type (fitXY)
tint	mask

3. Image button

1. Inheritance diagram

• ImageButton is a subclass of ImageView

2. Common attributes

Attributes	meaning
layout_height	Height, unit: dp (wrap_content, match_parent)
layout_weight	Width, unit: dp (wrap_content, match_parent)
src	Source (used to set the image source)
background	Background (used to set the background image)

4. Zoom in and out of images via buttons

1. Create an Android application

• Create an Android app viaEmpty Activity ZoomlamgeByButton
  
• Click the [finish] button
  

2. Prepare picture materials

• Add three pictures to the drawable file
  

3. String resource file

• String resource file -string.xml
  

<resources>
    <string name="app_name">通过按钮缩放图片</string>
    <string name=