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[英]How to call a MainActivity method from ViewHolder in RecyclerView.Adapter?
[英]Cant call a custom added method into my adapter (extends RecyclerView.Adapter<MyAdapter.ViewHolder>)
提前谢谢你,不要对我太苛刻,这是我的第一个问题。
我试图通过在我的适配器中声明一个名为addItem(String newItem)的方法,通过适配器向我的 recyclerView 添加一个新项目然后我尝试在点击浮动按钮时调用此方法,问题是该方法甚至没有当我点击cntrl+space时出现,如果我把它写下来,它会变成红色。 我已经尝试重建项目,但没有任何变化。 ¿关于如何解决它的任何想法?
主活动类
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
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);
}
}
}
addItem(String)
不是RecyclerView.Adapter
的方法,而是MyAdapter
子类的方法。 显然, RecyclerView.Adapter
不知道您的MyAdapter
和addItem(String)
。
你可以改变
private RecyclerView.Adapter mAdapter;
进入
private MyAdapter mAdapter;
或投mAdapter
。 例如
if (mAdater instanceof MyAdapter) {
((MyAdapter) mAdapter).addItem(...);
}
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