回收商查看项目 onClick

Question

我已经在 Google 上搜索了许多关于如何获取在回收站视图中单击的项目的可能性，但它们似乎都不起作用。下面的代码应该可以工作，但我不明白为什么不能。在 android studio 中，getPosition() 方法被划掉了。我的想法已经用完了，有没有办法至少可以为点击回收站视图的名称敬酒？

ViewHolder

public class ShoppingListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    public CardView cv;
    public TextView name;
    public TextView description;
    Context context;

    public ShoppingListViewHolder(View itemView) {
        super(itemView);
        cv = (CardView) itemView.findViewById(R.id.cardView);
        name = (TextView) itemView.findViewById(R.id.title);
        description = (TextView) itemView.findViewById(R.id.description);
        itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("RecyclerView", "onClick：" + getPosition());
            }
        });
    }


    public void bindView(int position) {

    }

    @Override
    public void onClick(View v) {
        Log.d("TAG", "onClick " + getPosition() + " " + name);
    }

适配器

public class MainShoppingListViewActivity extends AppCompatActivity {

    List<Data> list = new ArrayList<>();
    RecyclerView recyclerView;
    ShoppingListViewAdapter adapter;
    Context context;
    EditText listName;
    Firebase ref;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_shoppinglist_view);

        Firebase.setAndroidContext(this);
        ref = new Firebase("https://shoppinglistshare.firebaseio.com/");

        // Getting the recycler view, using the Recycler View
        recyclerView = (RecyclerView) findViewById(R.id.shopping_list_recycler_view);
        // The setLayoutManager which contains the main container where the Recycler View is contained
        recyclerView.setLayoutManager(new LinearLayoutManager(MainShoppingListViewActivity.this));

        // Floating action bar initiated, background color is set and then onClickListener to act when the
        // button is pressed to which the createDialogBox(); method is called
        FloatingActionButton addFloat = (FloatingActionButton) findViewById(R.id.fab);
        addFloat.setBackgroundTintList(ColorStateList.valueOf(Color
                .parseColor("#3F51B5")));
        addFloat.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Click action
                createDialogBox();
            }
        });
    }

    /*
    * This method is used to add a new item to the Recycler View
    */
    public void addNewShoppingListItem(String val) {
        ref = new Firebase("https://shoppinglistshare.firebaseio.com/");

        adapter = new ShoppingListViewAdapter(list, MainShoppingListViewActivity.this);
        recyclerView.setAdapter(adapter);

        adapter.addItem(new Data(val, "Created by: Me"));
        ref.child("List Name: ").setValue(val);
    }

    /*
     * This method is used to add a new item to the Recycler View
    */
    public void removeShoppingListItem(String val) {
        adapter = new ShoppingListViewAdapter(list, MainShoppingListViewActivity.this);
        recyclerView.setAdapter(adapter);

        adapter.addItem(new Data(val, "Created by: Me"));
    }

    /*
     * This method is called inside the float action bar to create a dialog box when the floating action button is pressed.
    */
    public void createDialogBox() {

        // Alert Dialog Builder
        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        // Using Layout Inflater class and assigned to a variable and using getLayout
        LayoutInflater inflater = this.getLayoutInflater();

        // Inflate and set the layout for the dialog
        // Pass null as the parent view because its going in the dialog layout.
        // Using the view class to inflate the layout.
        View rootView = inflater.inflate(R.layout.custom_alert_dialog, null);
        listName = (EditText) rootView.findViewById(R.id.ShoppinglistName);

        // Using the AlertDialog Builder created above as "builder" to set the view.
        builder.setView(rootView)
                .setPositiveButton("Create", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        String val = listName.getText().toString();
                        if (!val.isEmpty()) {
                            addNewShoppingListItem(val);
                        } else {
                            Toast.makeText(MainShoppingListViewActivity.this, "Please enter a value", Toast.LENGTH_SHORT).show();
                        }
                    }
                })
                // Show the dialog
                .show();
    }
}

日志

FATAL EXCEPTION: main
Process: familyshopshare.com.familyshopshare, PID: 17889
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
    at android.widget.Toast.<init>(Toast.java:102)
    at android.widget.Toast.makeText(Toast.java:259)
    at familyshopshare.com.familyshopshare.ShoppingListViewHolder$1.onClick(ShoppingListViewHolder.java:33)
    at android.view.View.performClick(View.java:5198)
    at android.view.View$PerformClick.run(View.java:21147)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5417)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

Answer 1

做了一些小的改动，这是我得到的解决方案。我打算将 onClick 更改为另一种方法，而不是它所在的位置。如果有任何关于如何使代码更好的建议，请告诉我，任何建议都非常感谢:)

public class ShoppingListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

public CardView cv;
public TextView name;
public TextView description;
Context context;

public ShoppingListViewHolder(View itemView) {
    super(itemView);
    cv = (CardView) itemView.findViewById(R.id.cardView);
    name = (TextView) itemView.findViewById(R.id.title);
    description = (TextView) itemView.findViewById(R.id.description);
    itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Data test = new Data(name.getText().toString(), description.getText().toString());
            Toast.makeText(v.getContext(), "onClick " +  test.getName(), Toast.LENGTH_SHORT).show();
            Log.d("RecyclerView", "onClick is this：" + getAdapterPosition());
        }
    });
}

@Override
public void onClick(View v) {
    Toast.makeText(context, "onClick " + getAdapterPosition() + " " + name, Toast.LENGTH_SHORT).show();
}

}

Answer 2

有几种方法可以做到这一点。就个人而言，我喜欢在适配器类的 onBindViewHolder 中设置监听器（无论你有你的viewholder）：

@Override
public void onBindViewHolder(ViewHolder holder, int position) {

   holder.YourTargetObject.setOnClickListener(new View.onClickListener(){
      public void onClick(View view){
       //do something
      }
   });

}