android – Recyclerview,我无法通过getChildAt(位置)获取项目视图.空对象引用

概述我在导航抽屉里面使用了recyclerView,我使用这个库 Twoway-view来获得点击和选择支持. 它工作得很好,我可以在每个位置的OnClick方法中更改文本和图标的颜色而没有问题： itemClickSupport.setOnItemClickListener(new ItemClickSupport.OnItemClickListener() { @Override 我在导航抽屉里面使用了recyclerVIEw,我使用这个库 Twoway-view来获得点击和选择支持.

它工作得很好,我可以在每个位置的OnClick方法中更改文本和图标的颜色而没有问题：

itemClickSupport.setonItemClickListener(new ItemClickSupport.OnItemClickListener() {        @OverrIDe        public voID onItemClick(RecyclerVIEw parent,VIEw vIEw,int position,long ID) {            TypedValue typedValue = new TypedValue();            MainActivity.this.gettheme().resolveAttribute(R.attr.colorAccent,typedValue,true);            final int color = typedValue.data;            //Todo Icon and text colors            for (int i = 0; i < drawerTitles.length; i++){                if (i == position){                    ImageVIEw imageVIEwDrawerIcon = (ImageVIEw) recyclerVIEwDrawer.getChildAt(i).findVIEwByID(R.ID.imageVIEwDrawerIcon);                    TextVIEw textVIEwDrawerTitle = (TextVIEw) recyclerVIEwDrawer.getChildAt(i).findVIEwByID(R.ID.textVIEwDrawerItemTitle);                    imageVIEwDrawerIcon.setcolorFilter(color);                    if(Build.VERSION.SDK_INT > 15){                        imageVIEwDrawerIcon.setimageAlpha(255);                    }else{                        imageVIEwDrawerIcon.setAlpha(255);                    }                    textVIEwDrawerTitle.setTextcolor(color);                    relativeLayout relativeLayoutDrawerItem = (relativeLayout) recyclerVIEwDrawer.getChildAt(i).findVIEwByID(R.ID.relativeLayoutDrawerItem);                    relativeLayoutDrawerItem.setFocusableIntouchMode(true);                }else{                    ImageVIEw imageVIEwDrawerIcon = (ImageVIEw) recyclerVIEwDrawer.getChildAt(i).findVIEwByID(R.ID.imageVIEwDrawerIcon);                    TextVIEw textVIEwDrawerTitle = (TextVIEw) recyclerVIEwDrawer.getChildAt(i).findVIEwByID(R.ID.textVIEwDrawerItemTitle);                    imageVIEwDrawerIcon.setcolorFilter(getResources().getcolor(R.color.md_text));                    if(Build.VERSION.SDK_INT > 15){                        imageVIEwDrawerIcon.setimageAlpha(138);                    }else{                        imageVIEwDrawerIcon.setAlpha(138);                    }                    textVIEwDrawerTitle.setTextcolor(getResources().getcolor(R.color.md_text));                    relativeLayout relativeLayoutDrawerItem = (relativeLayout) recyclerVIEwDrawer.getChildAt(i).findVIEwByID(R.ID.relativeLayoutDrawerItem);                    relativeLayoutDrawerItem.setFocusableIntouchMode(false);                }            }            //Todo Fragments (closedrawers before setfragment)            final Handler handler = new Handler();            handler.postDelayed(new Runnable() {                @OverrIDe                public voID run() {                    // Do something after some time                }            },250);            mDrawerLayout.closeDrawers();        }    });

问题是我想要访问该方法中的第一个项目,但在它之前(设置选择的第一个项目,使用不同的颜色等).

但是当我尝试获取OnClick方法之外的第一个项目时,我得到了崩溃(null引用)：

ImageVIEw imageVIEwDrawerIcon = (ImageVIEw) recyclerVIEwDrawer.getChildAt(0).findVIEwByID(R.ID.imageVIEwDrawerIcon);

所有代码：

// Setup RecyclerVIEw insIDe drawer    recyclerVIEwDrawer = (RecyclerVIEw) findVIEwByID(R.ID.recyclerVIEwDrawer);    recyclerVIEwDrawer.setHasFixedSize(true);    recyclerVIEwDrawer.setLayoutManager(new linearlayoutmanager(MainActivity.this));    ArrayList<DrawerItem> drawerItems = new ArrayList<>();    final String[] drawerTitles = getResources().getStringArray(R.array.drawer);    final TypedArray drawerIcons = getResources().obtainTypedArray(R.array.drawerIcons);    for (int i = 0; i < drawerTitles.length; i++) {        drawerItems.add(new DrawerItem(drawerTitles[i],drawerIcons.getDrawable(i)));    }    drawerIcons.recycle();    adapterDrawer = new DrawerAdapter(drawerItems);    recyclerVIEwDrawer.setAdapter(adapterDrawer);    // Here is the problem    ImageVIEw imageVIEwDrawerIcon2 = (ImageVIEw) recyclerVIEwDrawer.getChildAt(0).findVIEwByID(R.ID.imageVIEwDrawerIcon);    // RecyclerVIEw item Listener.    ItemClickSupport itemClickSupport = ItemClickSupport.addTo(recyclerVIEwDrawer);    itemClickSupport.setonItemClickListener(new ItemClickSupport.OnItemClickListener() {        @OverrIDe        public voID onItemClick(RecyclerVIEw parent,250);            mDrawerLayout.closeDrawers();        }    });

解决方法 在我的情况下,它的工作就像一个魅力

VIEw vIEwItem = recycleVIEw.getLayoutManager().findVIEwByposition(position);    VIEw icon = vIEwItem.findVIEwByID(R.ID.vIEw);

总结

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