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https://github.com/evant/yield-layout

Combine layouts in Android, opposite of how <include/> works.
https://github.com/evant/yield-layout

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Combine layouts in Android, opposite of how <include/> works.

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README 

        
YieldLayout

============



Have you ever had to create two almost-identical layout files because they had a few minor differences? Sure, you can fix it with `` but then you start ending up with layouts all over the place.



YieldLayout to the rescue! It works opposite of `` so you can combine one layout around another instead of inside it. After it does it's magic, you will have 0 extra views in your layout hierarchy, just like ``, so it's like it was never there.



![preview](https://raw.githubusercontent.com/evant/yield-layout/master/images/preview.png)



## Usage



You can create a layout file that has places to yield content.



```xml



    



    



    



    



    



```



Then you can create another file that uses that layout, filling in the yields.



```xml



    



    



```



By default child views are matched against `Yield`s in the order they are defined. However, if you

give your child views explicit id's, they will be matched against the `Yield` id's.



```xml



    

    



    

    



```



### ListViews



If you want to use this in a list adapter, you can't use the `YieldLayout` directly because it will try to add it's layout to it's parent which a listview doesn't allow. Instead, you can use `YieldLayoutInflater` which will return the final view to add instead of the `YieldLayout`.



```java

@Override

public View getView(int position, View convertView, ViewGroup parent) {

    if (convertView == null) {

        int layout = getItemViewType(position) == 0 ? R.layout.list_item_1 : R.layout.list_item_2;  

        convertView = YieldLayoutInflater.from(mContext).inflate(layout, parent, false);

    }

    return convertView;

}

```



Or if you are changeing the outer layout instead of the child views,



```java

@Override

public View getView(int position, View convertView, ViewGroup parent) {

    if (convertView == null) {

        int layout = getItemViewType(position) == 0 ? R.layout.layout_1 : R.layout.layout_2;  

        convertView = YieldLayoutInflater.from(mContext).inflate(R.layout.list_item, layout, parent, false);

    }

    return convertView;

}

```



### Different numbers of children



You may be wondering what happens if you don't specify as many child views for `YieldLayout` as there are `Yield`s. Too many children is an error because there is no way to know where to put the extra ones. Too few, however, will simply cause the extra `Yield`s to be removed.



Sometimes, however, you may depend on the `Yield` to correctly layout your views. For example,



```xml



    



    



```



If there is no matching child for `footer`, then it will be removed, and `content` won't lay out correctly. To fix this, you can add



```xml

    

```



which will keep the `Yield` view even if it's not replaced. Note that in this case, the `Yield` view will always have a size of 0.



### Layout Preview



The layout preview in Android Studio will show `Yield` placholder views so that you can see how they fit in your layout. If you define your `yield_layout` for your `YieldLayout`, that will correctly show as well.



If you are setting your `yield_layout` dynamically, you would think you could preview it by setting `tools:yield_layout` in your xml. Unfortunately, the `tools` namespace doesn't work with custom attributes. To get around this, you can set `app:tools_yield_layout` instead which will give an equivalent result.