RecyclerView高度隨Item自適應 GridLayoutManager和LinearLayoutManager都適用

標籤：布局

ScrollView嵌套RecyclerView時，android:layout_height=”wrap_content”並不起作用，RecyclerView會填充剩餘的整個螢幕空間，也就相當於android:layout_height=”match_parent”，通過重寫GridLayoutManager或LinearLayoutManager 的onMeasure方法進行可重設RecyclerView的高度。

這裡只給出GridLayoutManager的例子，LinearLayoutManager類似

a.設定LayoutManager

rvPhotos.setLayoutManager(new PhotoLayoutManage(this, 3));

b.RecyclerView的Adapter
Adapter中定義變數item中的height

private int itemHeight;public int getItemHeight(){ return itemHeight;}

在Adapter的ViewHolder構造方法中設定item項顯示後的高度

itemView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {                @Override                public boolean onPreDraw() {                    itemHeight=convertView.getMeasuredHeight();                    return true;                }            });

c.自訂GridLayoutManager重寫onMeasure方法

public class PhotoLayoutManage extends GridLayoutManager{        // RecyclerView高度隨Item自適應        public PhotoLayoutManage(Context context,int spanCount) {            super(context,spanCount);        }        @Override        public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, final int widthSpec,final int heightSpec) {            try {                 //不能使用   View view = recycler.getViewForPosition(0);                 //measureChild(view, widthSpec, heightSpec);                  // int measuredHeight  view.getMeasuredHeight();  這個高度不準確                    if(adapter!=null&&adapter.getItemHeight()>0) {                                               int measuredWidth = View.MeasureSpec.getSize(widthSpec);                        int measuredHeight = adapter.getItemHeight()+rvPhotos.getPaddingBottom()+rvPhotos.getPaddingTop();                        int line = adapter.getItemCount() / getSpanCount();                        if (adapter.getItemCount() % getSpanCount() > 0) line++;                        setMeasuredDimension(measuredWidth, measuredHeight * line);                    }else{                        super.onMeasure(recycler,state,widthSpec,heightSpec);                    }            }catch (Exception e){                super.onMeasure(recycler,state,widthSpec,heightSpec);            }        }    }

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RecyclerView高度隨Item自適應 GridLayoutManager和LinearLayoutManager都適用