java - 获取recyclerview中的按钮状态

Question

我正在使用回收 View ，并且我尝试仅在选定状态上设置按钮一次。

button 1 : when clicked set is as true .
button2 : when clicked set `button 1` to `false` state and then set `button 2` to `true`
button3: when clicked set `button 2` to `false` state and then set `button 3` to `true`

我的问题是如何让上一个按钮 View 将其设置为 false ？

public class MyCustomAdapterPackages extends RecyclerView.Adapter<MyCustomAdapterPackages.CustomViewHolderPackages> {


    private ArrayList<Packages> packages;
    private Context mContext;
int id=-1;
    public MyCustomAdapterPackages(Context context, ArrayList<Packages> packages) {
            this.packages = packages;
            this.mContext = context;

    }

    @Override
    public CustomViewHolderPackages onCreateViewHolder(ViewGroup viewGroup, int i) {
             View view = LayoutInflater.from(mContext).inflate(R.layout.package_row_item, null);
            CustomViewHolderPackages viewHolder = new CustomViewHolderPackages(view);
            return viewHolder;
    }

    @Override
    public void onBindViewHolder(final MyCustomAdapterPackages.CustomViewHolderPackages holder, final int position) {

            final Packages pa = packages.get(position);



            holder.PackageButton.setText(pa.getPackageName());
        holder.PackagePrice.setText(String.valueOf(pa.getPackagePrice()));
            holder.PackageButton.setBackground(ContextCompat.getDrawable(mContext, R.drawable.tab_bg_selector));


        holder.PackageButton.setId(position);
        holder.PackageButton.setTag(id);


            View.OnClickListener clickListener = new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {




                        if(id<0){
                            view.setSelected(true);
                            id=view.getId();
                        }
                        else{

                           if(((Button)holder.getTag(id)).isSelected()) {
                               view.findViewById(id).setSelected(false);
                               view.setSelected(true);
                               id=view.getId();
                           }
                            else{
                              id=view.getId();
                               view.setSelected(true);
                           }

                        }


                    }
            };

            //Handle click event on both title and image click
            holder.PackageButton.setOnClickListener(clickListener);
           // holder.PackagePrice.setOnClickListener(clickListener);

            holder.PackageButton.setTag(packages.get(position));
         //   holder.PackagePrice.setTag(packages.get(position));
     //   holder.viewGroup.addView(ll);
    }


    @Override
    public int getItemCount() {
            return (null != packages ? packages.size() : 0);
    }

    public class CustomViewHolderPackages extends RecyclerView.ViewHolder {


            protected Button PackageButton;
            protected TextView PackagePrice;

            public CustomViewHolderPackages(View view) {
                    super(view);
                    this.PackageButton = (Button) view.findViewById(R.id.PackageButton);
                    this.PackagePrice = (TextView) view.findViewById(R.id.PackagePrice);

            }

    }

}

日志错误:

Process: hesham.bestdealsoft.topline.elitedishes, PID: 15922
                                                                                     java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.view.View.isSelected()' on a null object reference
                                                                                         at hesham.bestdealsoft.topline.elitedishes.MyCustomAdapterPackages$1.onClick(MyCustomAdapterPackages.java:75)
                                                                                         at android.view.View.performClick(View.java:4848)
                                                                                         at android.view.View$PerformClick.run(View.java:20262)
                                                                                         at android.os.Handler.handleCallback(Handler.java:815)
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:104)
                                                                                         at android.os.Looper.loop(Looper.java:194)
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:5637)
                                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                                         at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959)
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754)

Answer 1

我找到了解决方案

我应该首先将回收 View 实例从外部类传递到我的自定义适配器

内部回收 View 适配器很薄，我可以通过它在回收 View 中的位置获取任何 View 并将其转换到 View 持有者，然后可以使用持有者做任何事情

这里是代码:

外部类:

        mRecyclerView2 = (RecyclerView) findViewById(R.id.list_Fragment);
    mRecyclerView2.setHasFixedSize(true);
    mLayoutManager = new LinearLayoutManager(this);
    mRecyclerView2.setLayoutManager(mLayoutManager);
    mAdapter2 = new MyCustomAdapterPackages(this, PackagesList,mRecyclerView2);
    mRecyclerView2.setAdapter(mAdapter2);
    mAdapter2.notifyDataSetChanged();

在客户适配器类中:

@Override
    public void onBindViewHolder(final MyCustomAdapterPackages.CustomViewHolderPackages holder, final int position) {

            final Packages pa = packages.get(position);



            holder.PackageButton.setText(pa.getPackageName());
        holder.PackagePrice.setText(String.valueOf(pa.getPackagePrice()));
            holder.PackageButton.setBackground(ContextCompat.getDrawable(mContext, R.drawable.tab_bg_selector));


        holder.PackageButton.setId(position);
        holder.PackageButton.setTag(id);


            View.OnClickListener clickListener = new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {



                        if(id<0){ // first time or default 
                            view.setSelected(true);
                            id=view.getId(); 
                        }
                        else{
                            CustomViewHolderPackages row = (CustomViewHolderPackages)mRecyclerView.findViewHolderForAdapterPosition(id); 

                           if( row.PackageButton.isSelected()) {
                               row.PackageButton.setSelected(false); // previous view 
                               view.setSelected(true); // current view
                               id=view.getId();
                           }
                            else{
                              id=view.getId();
                               view.setSelected(true);
                           }

                        }


                    }
            };

            //Handle click event
            holder.PackageButton.setOnClickListener(clickListener);

    }