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我想編寫我自己的recyclerview slector算法。到目前爲止，除了處理第一個選擇之外，我成功地部分編寫了代碼。基本上我想設置背景爲藍色選擇的項目，白色在別處（與ListView的setSelection相同）。RecyclerView抽屜 - 設置選擇
所以，這個想法是：
- 設置在適配器的onCreateViewHolder方法的第一個元素藍色背景。
- 在ActivityMain，定義一個intance查看變量navMenuSelection存儲當前選擇
- 在recyclerView的onclick監聽器，設置點擊視圖藍，背景navMenuSelection，爲白色的背景，並更新navMenuSelection到點擊視圖
所有工作除外： 1.無法用第一個視圖初始化navMenuSelection。試圖用mDrawerLayout.getChildAt（0）在onPostCreate方法，但返回null
任何想法將不勝感激。
public class ActivityMain extends AppCompatActivity {
private View navMenuSelection = null; // Select current view
protected void onCreate(Bundle savedInstanceState) {
// ALL THE CODES TO DEFINE RECYCLERVIEW
mRecyclerView.addOnItemTouchListener(new RecycleTouchListener(this, new ClickListner() {
@Override
public void onClick(View view, int position) {
if(view != navMenuSelection){
setNavItemSelected(view);
removeNavItemSelected(navMenuSelection);
navMenuSelection = view;
mDrawerLayout.closeDrawers();
}
}
}));
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
mDrawerToggle.syncState();
navMenuSelection = mDrawerLayout.getChildAt(0);
}
@Override
public void onSaveInstanceState(Bundle savedInstanceState){
//savedInstanceState.put???("currselection", navMenuSelection); // HOW TO DO THAT
super.onSaveInstanceState(savedInstanceState);
}
public void setNavItemSelected(View v){
if(v!= null) {
v.setBackgroundColor(R.color.BLUE));
}
}
public void removeNavItemSelected(View v){
if(v!= null) {
v.setBackgroundColor(R.color.WHITE));
}
}
}
適配器類別（移動onClick事件後，適配器）
public class NavDrawerAdapter extends RecyclerView.Adapter<NavDrawerAdapter.ViewHolder> {
private String[] mNavTitles; // stores title
private int[] mIcons; // stores icon
private Context context;
private int oldpostion = 0;
public NavDrawerAdapter(Context context, String Titles[], int[] Icons){
this.context = context;
mNavTitles = Titles;
mIcons = Icons;
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView textView;
ImageView imageView;
public ViewHolder (View itemView) {
super(itemView);
textView = (TextView) itemView.findViewById(R.id.title);
imageView = (ImageView) itemView.findViewById(R.id.icon);
}
}
@Override
public NavDrawerAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.navdrawer_item,parent,false);
return new ViewHolder(v,viewType);
}
@Override
public void onBindViewHolder(NavDrawerAdapter.ViewHolder holder, final int position) {
holder.textView.setText(mNavTitles[position]);
holder.imageView.setImageResource(mIcons[position]);
if(position == 0) {
setNavItemSelected(holder.itemView);
}
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(position != oldpostion){
setNavItemSelected(v);
//removeNavItemSelected(OLD VIEW);
oldpostion = position;
}
}
});
}
@Override
public int getItemCount() {
return mNavTitles.length;
}
@Override
public int getItemViewType(int position) {
return 1;
}
public void setNavItemSelected(View v){
if(v!= null) {
v.setBackgroundColor(context.getResources().getColor(R.color.navdrawer_item_selected_bg));
TextView tview = (TextView) v.findViewById(R.id.title);
tview.setTextColor(context.getResources().getColor(R.color.navdrawer_item_selected_text));
}
}
public void removeNavItemSelected(View v){
if(v!= null) {
v.setBackgroundResource(R.drawable.list_selector_nav_drawer);
TextView tview = (TextView) v.findViewById(R.id.title);
tview.setTextColor(context.getResources().getColorStateList(R.color.list_selector_nav_drawer_text));
}
}
}
更好地把它放在recyclerview的適配器上。顯示適配器代碼 – Genevieve
right ur ..已將代碼移至適配器..但是，無法從位置獲取oldviewholder。 – abdfahim
顯示適配器的代碼 – Genevieve