I am using a recyclerView inside my navigation drawer and I am using this library Twoway-view to get click and selection support.
It works perfectly and I can change the color of the text and the icons without problems inside OnClick method for each position:
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();
}
});
The problem is that I want to access to the first item like in that method, but before it (to set the first item selected, with different color, etc).
But I get a crash (null reference) when I try to get the first item outside OnClick method:
ImageView imageViewDrawerIcon = (ImageView) recyclerViewDrawer.getChildAt(0).findViewById(R.id.imageViewDrawerIcon);
All code:
// 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, 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();
}
});
A LayoutManager is responsible for measuring and positioning item views within a RecyclerView as well as determining the policy for when to recycle item views that are no longer visible to the user.
In my case it,is work like a charm
View viewItem = recycleView.getLayoutManager().findViewByPosition(position);
View icon = viewItem.findViewById(R.id.view);
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