LayoutInflater

Android一分钟

• 作用：把xml类型的布局转化成相应的View对象

  1. LayoutInflater inflater = getLayoutInflater(); //调用Activity的getLayoutInflater()
  2. LayoutInflater inflater = LayoutInflater.from(context);
  3. LayoutInflater localinflater =(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

• inflater.inflater

  • inflate(int resource, ViewGroup root, boolean attachToRoot)
    

  • inflate(int resource, ViewGroup root)//attachToRoot = true
    

  • If attachToRoot is set to true, then the layout file specified in the first parameter is inflated and attached to the ViewGroup specified in the second parameter.

    • 如果attachToRoot＝true，view对象将直接绑定到ViewGroup

  • When attachToRoot is false, the layout file from the first parameter is inflated and returned as a View.

    • 如果attachToRoot＝false，view对象将被填充并且返回该对象，但是不会绑定到ViewGroup上，需要手动addView()绑定

  • attachToRoot 必须设置为 false的情况，例如：

    • recyclerview

      • public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            LayoutInflater inflater = LayoutInflater.from(getActivity());
            View view = inflater.inflate(android.R.layout.list_item_recyclerView, parent, false);
            return new ViewHolder(view);
        }
        

      • 由于recyclerview会负责填充和绑带viewholder

    • Fragment

      • 由于FragmentManager负责add, remove and replace Fragments

        public View onCreateView(LayoutInflater inflater, ViewGroup parentViewGroup, Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.fragment_layout, parentViewGroup, false);
            return view;
        }
        

• 参考 https://www.bignerdranch.com/blog/understanding-androids-layoutinflater-inflate/

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