无法将自定义添加的方法调用到我的适配器中(扩展了RecyclerView.Adapter< MyAdapter.ViewHolder>) [英] Cant call a custom added method into my adapter (extends RecyclerView.Adapter<MyAdapter.ViewHolder>)
问题描述
预先感谢您,不要对我很刻薄,这是我的第一个问题.
Thank you in advance and dont be very hard with me, it is my first question.
我试图通过在适配器中声明一个名为 addItem(String newItem) 的方法,通过适配器向recyclerView添加新物品.然后,当浮动按钮被按下时,我尝试调用此方法,问题是当我按下 cntrl + space 时,该方法甚至都没有出现,如果我写下来,它会变成红色.我已经尝试过重建项目,并且没有任何变化.¿关于如何解决它的任何想法?
I was trying to add a new item to my recyclerView through the adapter by declaring a method in my adapter called addItem(String newItem) Then I tried to call this method when the floating button is clikced and the problem is that the method does not even appear when i hit cntrl+space and if i write it down it gets on red. I have already tried to rebuild the project and nothing changes. ¿Any ideas about how to solve it?
MainActivity类
MainActivity class
package com.example.sakur.recyclerviewapp;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
private FloatingActionButton mFloatingActionButton;
private List<String> recyclerItems = Collections.emptyList();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
recyclerItems = new ArrayList<>();
recyclerItems.add("First item");
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new MyAdapter(recyclerItems);
mRecyclerView.setAdapter(mAdapter);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.floating_action_button);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String itemNuevo = "New Card";
mAdapter.addItem(itemNuevo);
Snackbar.make(view, "Item added successfully", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
和MyAdapter类
and the MyAdapter class
package com.example.sakur.recyclerviewapp;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.Collections;
import java.util.List;
/**
* Created by Sakur on 19/12/2015.
*/
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private List<String> mDataset= Collections.emptyList();
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(List<String> myDataset) {
mDataset = myDataset;
}
public void addItem(String newItem){
mDataset.add(newItem);
notifyDataSetChanged();
}
// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_card, parent, false);
// set the view's size, margins, paddings and layout parameters
//...
ViewHolder vh = new ViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// - get element from your dataset at this position
// - replace the contents of the view with that element
holder.mTextView.setText(mDataset.get(position));
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mDataset.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView mTextView;
public ImageView mImageView;
public ViewHolder(View v) {
super(v);
mTextView = (TextView) v.findViewById(R.id.text_card);
}
}
}
推荐答案
addItem(String)
不是 RecyclerView.Adapter
的方法,而是您的MyAdapter
子类.显然, RecyclerView.Adapter
不知道您的 MyAdapter
和 addItem(String)
的存在.
addItem(String)
is not a method of RecyclerView.Adapter
, but of your MyAdapter
subclass. Obviously, RecyclerView.Adapter
has no knowledge of the existence neither of your MyAdapter
nor of your addItem(String)
.
您可以更改
private RecyclerView.Adapter mAdapter;
进入
private MyAdapter mAdapter;
或强制转换 mAdapter
.例如
if (mAdater instanceof MyAdapter) {
((MyAdapter) mAdapter).addItem(...);
}
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