鸿蒙开源三方组件--跨平台自适应布局yoga组件-开源-知优网

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介绍

yoga是facebook打造的一个跨IOS、Android、Window平台在内的布局引擎，兼容Flexbox布局方式，让界面更加简单。

Yoga官网：https://facebook.github.io/yoga/

官网上描述的特性包括：

完全兼容Flexbox布局，遵循W3C的规范
支持java、C#、Objective-C、C四种语言
底层代码使用C语言编写，性能不是问题
支持流行框架如React Native

目前在已开源的鸿蒙组件(https://gitee.com/openharmony-tpc/yoga)的功能现状如下：

native层和接口已经打通
支持自定义xml属性来控制布局(通过YogaLayout)
设置布局中不支持Image控件(onDrawCanvas暂不支持主动回调，所以yoga没办法扫描到它)，请使用Text控件替代
不支持VirtualYogaLayout

如何使用

首先我们在MainAbility中定义界面路由。

publicclassMainAbilityextendsAbility{
@Override
publicvoidonStart(Intentintent){
super.onStart(intent);
super.setMainRoute(MainAbilitySlice.class.getName());
addActionRoute("action.dydrawnode.slice",DynamicsDrawNodeSlice.class.getName());
addActionRoute("action.showrow.slice",ShowRowAbilitySlice.class.getName());
addActionRoute("action.inflate.slice",BenchmarkInflateAbilitySlice.class.getName());
}
}

然后我们来到MainAbilitySlice,其实就是做了一个向其他界面跳转的动作，并提前加载yoga的so库。

publicclassMainAbilitySliceextendsAbilitySlice{
static{
System.loadLibrary("yoga");
System.loadLibrary("yogacore");
System.loadLibrary("fb");
}
@Override
publicvoidonStart(Intentintent){
super.onStart(intent);
setUIContent(ResourceTable.Layout_main_layout);
Buttonbtn0=(Button)findComponentById(ResourceTable.Id_btn_1);
btn0.setClickedListener(component->{
Intentintent1=newIntent();
Operationoperation=newIntent.OperationBuilder()
.withAction("action.dydrawnode.slice")
.build();
intent1.setOperation(operation);
startAbilityForResult(intent1,1);
});
Buttonbtn2=(Button)findComponentById(ResourceTable.Id_btn_2);
btn2.setClickedListener(component->{
Intentintent1=newIntent();
Operationoperation=newIntent.OperationBuilder()
.withAction("action.showrow.slice")
.build();
intent1.setOperation(operation);
startAbilityForResult(intent1,1);
});
Buttonbtn1=(Button)findComponentById(ResourceTable.Id_btn_3);
btn1.setClickedListener(component->{
Intentintent1=newIntent();
Operationoperation=newIntent.OperationBuilder()
.withAction("action.inflate.slice")
.build();
intent1.setOperation(operation);
startAbilityForResult(intent1,1);
});
}
@Override
publicvoidonActive(){
super.onActive();
}
@Override
publicvoidonForeground(Intentintent){
super.onForeground(intent);
}
}

第一个演示界面

这里yoga向我们展示了动态布局的能力，效果图如下：

实现的代码如下：

publicclassDynamicsDrawNodeSliceextendsAbilitySlice{
privatestaticfinalintVIEW_WIDTH=200;
privatestaticfinalintVIEW_HEIGHT=200;
privateArrayList<Component>mViewList=newArrayList<>();
privateArrayList<YogaNode>mYogaNodeList=newArrayList<>();
privateint[][]colors=newint[][]{
newint[]{0xff6200ea,0xff651fff,0xff7c4dff,0xffb388ff},
newint[]{0xffd50000,0xffff1744,0xffff5252,0xffff8a80},
newint[]{0xffc51162,0xfff50057,0xffff4081,0xffff80ab},
newint[]{0xffaa00ff,0xffd500f9,0xffe040fb,0xffea80fc}
};
@Override
protectedvoidonStart(Intentintent){
super.onStart(intent);
PositionLayoutcontainer=newPositionLayout(this);
DisplayAttributesdisplayAttributes=DisplayManager.getInstance().getDefaultDisplay(this).get().getAttributes();
floatscreenWidth=displayAttributes.width;
floatscreenHeight=displayAttributes.height;
YogaNoderoot=newYogaNodeJNIFinalizer();
root.setWidth(screenWidth);
root.setHeight(screenHeight);
root.setFlexDirection(YogaFlexDirection.COLUMN);
createRowNodeAndView(root,0);
createRowNodeAndView(root,1);
createRowNodeAndView(root,2);
createRowNodeAndView(root,3);
root.calculateLayout(screenWidth,screenHeight);
for(inti=0;i<mViewList.size();i++){
Componentcomponent=mViewList.get(i);
YogaNodeyogaNode=mYogaNodeList.get(i);
YogaNodeyogaNodeOwner=yogaNode.getOwner();
component.setTranslationX(yogaNodeOwner.getLayoutX()+yogaNodeOwner.getLayoutX());
component.setTranslationY(yogaNodeOwner.getLayoutY()+yogaNodeOwner.getLayoutY());
component.setLeft((int)(yogaNodeOwner.getLayoutX()+yogaNode.getLayoutX()));
component.setTop((int)(yogaNodeOwner.getLayoutY()+yogaNode.getLayoutY()));
container.addComponent(component);
}
super.setUIContent(container);
}
privatevoidcreateRowNodeAndView(YogaNoderoot,intindex){
YogaNoderow=newYogaNodeJNIFinalizer();
row.setHeight(VIEW_HEIGHT);
row.setWidth(VIEW_WIDTH*4);
row.setFlexDirection(YogaFlexDirection.ROW);
row.setMargin(YogaEdge.ALL,20);
for(inti=0;i<4;i++){
YogaNodeyogaNode=newYogaNodeJNIFinalizer();
yogaNode.setWidth(VIEW_WIDTH);
yogaNode.setHeight(VIEW_HEIGHT);
Componentcomponent=createView(colors[index][i]);
row.addChildAt(yogaNode,i);
mYogaNodeList.add(yogaNode);
mViewList.add(component);
}
root.addChildAt(row,index);
}
privateComponentcreateView(intcolor){
Componentview=newComponent(this);
ShapeElementbackground=newShapeElement();
background.setRgbColor(convertColor(color));
view.setBackground(background);
ComponentContainer.LayoutConfiglayoutConfig=newAdaptiveBoxLayout.LayoutConfig(VIEW_WIDTH,VIEW_HEIGHT);
view.setLayoutConfig(layoutConfig);
returnview;
}
/**
*转换颜色
*@paramcolor
*@returnRgbColor
*/
publicRgbColorconvertColor(intcolor){
intcolorInt=color;
intred=(colorInt&0xff0000)>>16;
intgreen=(colorInt&0x00ff00)>>8;
intblue=(colorInt&0x0000ff);
returnnewRgbColor(red,green,blue);
}
}

代码中定义了一个root根布局，宽高为屏幕的宽高，接着定义了四个行布局，并向每个行布局里添加4个子布局，最重要的是在调用root.calculateLayout(screenWidth, screenHeight)后，便将每个子布局的位置给确定了下来，然后根据获取到的每个布局的参数，给每个Component设置位置。该演示只是借助yoga组件来确定每个Component位置，真正使渲染生效的还是基于鸿蒙的原生控件。

第二个演示界面

接下来展示如何使用yoga组件在xml里通过填写属性来控制item位置的能力，效果图如下：

代码如下：

<?xmlversion="1.0"encoding="utf-8"?>
<com.facebook.yoga.openharmony.YogaLayout
xmlns:ohos="http://schemas.huawei.com/res/ohos"
xmlns:yoga="http://schemas.huawei.com/apk/res-auto"
ohos:height="match_parent"
ohos:width="match_parent"
>
<com.facebook.yoga.openharmony.YogaLayout
ohos:height="60vp"
ohos:width="match_content"
yoga:yg_alignItems="center"
yoga:yg_flexDirection="row"
yoga:yg_marginHorizontal="15"
yoga:yg_marginStart="15"
yoga:yg_marginTop="50"
ohos:background_element="$graphic:item_element"
>
<Text
ohos:height="50vp"
ohos:width="50vp"
ohos:background_element="$media:icon"
yoga:yg_flex="0"
yoga:yg_marginStart="15"
/>
<Text
ohos:height="50vp"
ohos:width="220vp"
ohos:text="Hello.IamYoga!"
ohos:text_color="#000000"
yoga:yg_flex="1"
yoga:yg_marginStart="15"
ohos:text_size="20fp"
/>
</com.facebook.yoga.openharmony.YogaLayout>
<com.facebook.yoga.openharmony.YogaLayout
ohos:background_element="$graphic:item_element"
ohos:height="60vp"
ohos:width="match_content"
yoga:yg_alignItems="center"
yoga:yg_flexDirection="row"
yoga:yg_marginHorizontal="15"
yoga:yg_marginTop="20"
yoga:yg_marginStart="15"
>
<Text
ohos:height="50vp"
ohos:width="50vp"
ohos:background_element="$media:icon"
yoga:yg_flex="0"
yoga:yg_marginStart="15"
/>
<Text
ohos:height="50vp"
ohos:width="250vp"
ohos:text="Iamalayoutengine!"
ohos:text_color="#000000"
yoga:yg_flex="1"
yoga:yg_marginStart="15"
ohos:text_size="20fp"
/>
</com.facebook.yoga.openharmony.YogaLayout>
<com.facebook.yoga.openharmony.YogaLayout
ohos:background_element="$graphic:item_element"
ohos:height="60vp"
ohos:width="match_content"
yoga:yg_alignItems="center"
yoga:yg_flexDirection="row"
yoga:yg_marginHorizontal="15"
yoga:yg_marginTop="20"
>
<Text
ohos:height="50vp"
ohos:width="50vp"
ohos:background_element="$media:icon"
yoga:yg_flex="0"
yoga:yg_marginStart="15"
/>
<Text
ohos:height="50vp"
ohos:width="250vp"
ohos:text="Irunnatively."
ohos:text_color="#000000"
yoga:yg_flex="1"
yoga:yg_marginStart="15"
ohos:text_size="20fp"
/>
</com.facebook.yoga.openharmony.YogaLayout>
<com.facebook.yoga.openharmony.YogaLayout
ohos:background_element="$graphic:item_element"
ohos:height="60vp"
ohos:width="match_content"
yoga:yg_alignItems="center"
yoga:yg_flexDirection="row"
yoga:yg_marginHorizontal="15"
yoga:yg_marginTop="20"
>
<Text
ohos:height="50vp"
ohos:width="50vp"
ohos:background_element="$media:icon"
yoga:yg_flex="0"
/>
<Text
ohos:height="50vp"
ohos:width="200vp"
ohos:text="SoI\'mfast."
ohos:text_color="#000000"
yoga:yg_flex="1"
yoga:yg_marginStart="15"
ohos:text_size="20fp"
/>
</com.facebook.yoga.openharmony.YogaLayout>
<com.facebook.yoga.openharmony.YogaLayout
ohos:background_element="$graphic:item_element"
ohos:height="60vp"
ohos:width="match_content"
yoga:yg_alignItems="center"
yoga:yg_flexDirection="row"
yoga:yg_marginHorizontal="15"
yoga:yg_marginTop="20"
>
<Text
ohos:height="50vp"
ohos:width="50vp"
ohos:background_element="$media:icon"
yoga:yg_flex="0"
/>
<Text
ohos:height="50vp"
ohos:width="200vp"
ohos:text="Whoareyou?"
ohos:text_color="#000000"
yoga:yg_flex="1"
yoga:yg_marginStart="15"
ohos:text_size="20fp"
/>
</com.facebook.yoga.openharmony.YogaLayout>
</com.facebook.yoga.openharmony.YogaLayout>

这里YogaLayout其实可以看成FlexBox(详情请参考附录：FlexBox科普)，可以通过参数调节子布局位置，我们可以使用YogaLayout上的yoga:yg_alignItems="center"属性使得item居中显示，并通过yoga:yg_flexDirection="row"属性使得之item横向排列。子item也可以通过设置yoga:yg_flex="1"来调整自己的权重。更多属性的使用大家也可以下载项目亲自体验。

集成方式

自行编译工程entity、yoga、yoga_layout、fb生成libyoga.so、libfb.so、libyogacore.so。

将其添加到要集成的libs文件夹内，在entity的gradle内添加如下代码。

方式一：

通过library生成har包，添加har包到libs文件夹内。

在entry的gradle内添加如下代码：

implementationfileTree(dir:'libs',include:['*.jar','*.har'])

方式二：

allprojects{
repositories{
mavenCentral()
}
}
implementation'io.openharmony.tpc.thirdlib:yoga-layout:1.0.0'
implementation'io.openharmony.tpc.thirdlib:yoga-yoga:1.0.0'
implementation'io.openharmony.tpc.thirdlib:yoga-fb:1.0.0'

附录1：FlexBox科普

布局的传统解决方案，基于盒状模型，依赖display属性，position属性，float属性。它对于那些特殊布局非常不方便，比如，垂直居中就不容易实现。2009年，W3C提出了一种新的方案：flex。可以简便、完整、响应式地实现各种界面布局。目前，该方案已经得到了所有浏览器的支持。采用Flex布局的元素，称为Flex容器(flex container)，简称“容器”。它的所有子元素置动成为容器成员，称为Flex项目(flex item)，简称“项目”。

容器默认存在两根轴：水平的主轴(main axis)和垂直的交叉轴(cross axis)。主轴的开始位置(与边框的交叉点)叫main start，结束位置叫main end;交叉轴的开始位置叫cross start，结束位置叫cross end。项目默认沿主轴排列。单个项目占据的主轴空间叫main size，占据的交叉轴空间叫cross size。