Common Style

0.4 cn

All of weex tags share some common style rules

Box Model

Weex box model based on the CSS box model, all of weex elements can be considered as boxes. The term "box model" is used when talking about design and layout. The box model is essentially a box that wraps around every HTML element. It consists of margins, borders, paddings, and the actual content.

you can use the definition below in weex box model.

• width: length type, default value 0
• height: length type, default value 0
• padding: length type, default value 0, (space around content, between element content and the element border)
  • padding-left: length type, default value 0
  • padding-right: length type, default value 0
  • padding-top: length type, default value 0
  • padding-bottom: length type, default value 0
• margin: length type, default value 0, (space around elements, outside the border)
  • margin-left: length type, default value 0
  • margin-right: length type, default value 0
  • margin-top: length type, default value 0
  • margin-bottom: length type, default value 0

• border

  • border-style: values solid | dashed | dotted, default value solid
    • border-left-style: values solid | dashed | dotted, default value solid
    • border-top-style: values solid | dashed | dotted, default value solid
    • border-right-style: values solid | dashed | dotted, default value solid
    • border-bottom-style: values solid | dashed | dotted, default value solid
  • border-width: length type, non-negative, default value 0 DO NOT use border-width:1. There is a default viewport <viewport width="750">, if the actual width of a device is 720px, then border-width:1 will be border-width:0.96. As weex do not support sub-pixel, this border would not be rendered.
    • border-left-width: length type, non-negative, default value 0
    • border-top-width: length type, non-negative, default value 0
    • border-right-width: length type, non-negative, default value 0
    • border-bottom-width: length type, non-negative, default value 0
  • border-color: color type, default value #000000
    • border-left-color: color type, default value #000000
    • border-top-color: color type, default value #000000
    • border-right-color: color type, default value #000000
    • border-bottom-color: color type, default value #000000
  • border-radius: length type, default value 0, (rounded borders to elements , default value is 0 meaning right angle )

  Although the the default overflow style is overflow:hidden in android, a view will not be clipped by its parents' border-radius. This only happens on Android, it works fine on iOS.

  • border-bottom-left-radius: length type, non-negative, default value 0
  • border-bottom-right-radius: length type, non-negative, default value 0
  • border-top-left-radius: length type, non-negative, default value 0
  • border-top-right-radius: length type, non-negative, default value 0

Notes: The rule of border-radius for a specific corner such as border-top-left-radius is not currently supported for component <image> and <text>.

Weex box model uses border-box as the default value of box-sizing, meaning the width and height properties includes content, padding and border, but not the margin.

example:

<template>
  <div>
    <image src="..." style="width: 400; height: 200; margin-left: 20;"></image>
  </div>
</template>

Flexbox

Weex box style model based on the CSS flexbox, ensures that elements behave predictably and the page layout can accommodates to different screen sizes and different display devices.

Flexbox consists of flex containers and flex items. If a weex element can containing other elements, it is a flex container.

Notice that the old version of flexbox specification has differences with the new ones, such as whether or not to support wrapping. This is described at w3c's working drafts, and you should notice the differences among them. Also notice that the old version is only supported below the 4.4 version of android.

Flex container

Flexbox is the default and only style model in Weex, so you don't have to add display: flex; in a container.

• flex-direction: values row | column, default value column

The flex-direction property specifies the direction of the flexible items inside the flex container. Default value is column (top-to-bottom).

• justify-content: values flex-start | flex-end | center | space-between, default value flex-start

The justify-content property horizontally aligns the flexible container's items when the items do not use all available space on the main-axis. Default value is flex-start meaning the flex items are positioned at the beginning of the container. flex-end means the items are positioned at the end of the container. center means the items are positioned at the center of the container. space-between means the items are positioned with space between the lines.

• align-items: values stretch | flex-start | center | flex-end, default value stretch

The align-items property vertically aligns the flexible container's items when the items do not use all available space on the cross-axis. Default value is stretch meaning the items are stretched to fit the container. flex-start means the items are positioned at the top of the container; flex-end means the items are positioned at the bottom of the container; center means items are positioned at the center of the container (vertically).

Flex item

• flex: number type, default value 0

the flex property specifies the length of the flex item, relative to the rest of the flex items inside the same container. If all of the flex items set flex: 1, they will have equal width or height on direction of flex container's flex-direction. If there are two flex items, with one setting flex: 1, and the other setting flex: 2, the first one will take 1/3 container space, and the second one will take 2/3 container space. If all of flex items don't set flex, they will be aligned depending on the container's justify-content property.

Examples

a list of images with equal scales align at the vertical axis:

<template>
  <div style="width: 300; height: 100;">
    <image src="..." style="flex: 1;"></image>
    <image src="..." style="flex: 1;"></image>
    <image src="..." style="flex: 1;"></image>
  </div>
</template>

a image with fixed width aligns with a stretched text:

<template>
  <div style="width: 300; height: 100;">
    <image src="..." style="width: 100; height: 100;"></image>
    <text style="flex: 1;">...</text>
  </div>
</template>

mixed direction alignment:

<template>
  <div style="width: 100;">
    <image src="..." style="width: 100; height: 100;"></image>
    <div style="flex-direction: row;">
      <text style="flex: 2; font-size: 32;">title</text>
      <text style="flex: 1; font-size: 16;">$100</text>
    </div>
  </div>
</template>

one text align left , the other float right:

<template>
<div style="flex-direction: row; justify-content: space-between;">
   <text>WEEX</text>
   <text>2016-05-08</text>
</div>
</template>

Position

we can use properties below to control placement of weex tag

• position: values relative | absolute | fixed | sticky, default value relative

relative means the item is positioned relative to its normal position. absolute means the item is positioned relative to its container. fixed keeps the elements position fixed when the page is scrolling. sticky keeps elements positioned inside the viewport as "stuck" at the top or "relative" at its original place depending on whether does it about to scroll out of the view.

• top: number type, default value 0, upward offset value
• bottom: number type, default value 0, downward offset value
• left: number type, default value 0, leftward offset value
• right: number type, default value 0, rightward offset value

Examples

<template>
  <div style="flex-direction: column;">
    <div style="height: 3000;">
      <image src="..." style="top: 50; left: 50; ..."></image>
    </div>
    <div style="height: 3000;">
      <image src="..." style="position: sticky; ..."></image>
    </div>
    <div style="height: 3000;">
      <image src="..." style="position: absolute; top: 50; left: 50; ..."></image>
    </div>
  </div>
</template>

Other Common Style

• opacity
• background-color

Type of Style Value

• length type
• number type
• color type (The list of color keywords.)
• enumerated type

Simple Step

These up-to-down steps may help you to plan the whole style of weex pages.

1. overall style: divide the whole page to different parts
2. flex alignment: align boxes in every part of page
3. position box: place box, set offset
4. element specific style: set styles for certain element if needed