Java 如何将arraylist从适配器传递到片段?
实际上,我是从RecyclerAdapter在ArrayList中添加对象的,我已经编写了一个函数,用于在适配器中获取ArrayList。我是从MainActivity中的该函数获取ArrayList的。但每当我试图将该ArrayList从MainActivity传递到片段时,它都会给出NullPointer(空值) 帮帮我Java 如何将arraylist从适配器传递到片段?,java,android,android-fragments,arraylist,android-activity,Java,Android,Android Fragments,Arraylist,Android Activity,实际上,我是从RecyclerAdapter在ArrayList中添加对象的,我已经编写了一个函数,用于在适配器中获取ArrayList。我是从MainActivity中的该函数获取ArrayList的。但每当我试图将该ArrayList从MainActivity传递到片段时,它都会给出NullPointer(空值) 帮帮我 package com.example.codingmounrtain.addtocartbadgecount.adapter; import android.conte
package com.example.codingmounrtain.addtocartbadgecount.adapter;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.codingmounrtain.addtocartbadgecount.activity.MainActivity;
import com.example.codingmounrtain.addtocartbadgecount.ModelClasses.Movie;
import com.example.codingmounrtain.addtocartbadgecount.R;
import com.example.codingmounrtain.addtocartbadgecount.interfaces.AddorRemoveCallbacks;
import com.squareup.picasso.Picasso;
import java.util.ArrayList;
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyViewHolder> {
ArrayList<Movie> cartmovies = new ArrayList<>();
public interface Listener {
void onSelectMovie(int position);
}
Context context;
private final ArrayList<Movie> movies;
private final Listener listener;
public RecyclerAdapter(Context context, ArrayList<Movie> movies,Listener listener) {
this.context = context;
this.movies = movies;
this.listener = listener;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.row_layout,parent,false);
return new MyViewHolder(view);
}
@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
holder.productName.setText(movies.get(position).getTitle());
Picasso.with(context).load(movies.get(position).getPhoto()).centerCrop().resize(400,400).into(holder.productImage);
holder.productImage.setImageResource(movies.get(position).getPhoto());
holder.productImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
listener.onSelectMovie(position);
}
});
holder.addRemoveBt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(!movies.get(position).isAddedTocart())
{
Log.v("tej","tej");
movies.get(position).setAddedTocart(true);
Log.v("t","t");
holder.addRemoveBt.setText("Remove");
Movie movie = movies.get(position);
cartmovies.add(movie);
Log.v("t","t");
if(context instanceof MainActivity)
{
((AddorRemoveCallbacks)context).onAddProduct();
}
}
else
{
movies.get(position).setAddedTocart(false);
Movie movie = movies.get(position);
cartmovies.remove(movie);
holder.addRemoveBt.setText("Add");
((AddorRemoveCallbacks)context).onRemoveProduct();
}
}
});
}
public ArrayList<Movie> getArrayList(){
return cartmovies;
}
@Override
public int getItemCount() {
return movies.size();
}
class MyViewHolder extends RecyclerView.ViewHolder{
ImageView productImage;
TextView productName;
Button addRemoveBt;
public MyViewHolder(View itemView) {
super(itemView);
productImage=(ImageView) itemView.findViewById(R.id.productImageView);
productName=(TextView) itemView.findViewById(R.id.productNameTv);
addRemoveBt=(Button)itemView.findViewById(R.id.addButton);
}
}
}
package com.example.codingmounrtain.addtocartbadgecount.adapter;
导入android.content.Context;
导入android.support.v7.widget.RecyclerView;
导入android.util.Log;
导入android.view.LayoutInflater;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.Button;
导入android.widget.ImageView;
导入android.widget.TextView;
导入com.example.codingmounrtain.addtocartbadgecount.activity.MainActivity;
导入com.example.codingmounrtain.addtocartbadgecount.ModelClasses.Movie;
导入com.example.codingmounrtain.addtocartbadgecount.R;
导入com.example.codingmounrtain.addtocartbackcount.interfaces.AddorRemoveCallbacks;
导入com.squareup.picasso.picasso;
导入java.util.ArrayList;
公共类RecyclerAdapter扩展了RecyclerView.Adapter{
ArrayList=newArrayList();
公共接口侦听器{
无效选择电影(int位置);
}
语境;
私人电影;
私人最终倾听者;
公共回收器适配器(上下文、ArrayList电影、侦听器){
this.context=上下文;
这部电影=电影;
this.listener=listener;
}
@凌驾
公共MyViewHolder onCreateViewHolder(视图组父级,int-viewType){
View-View=LayoutInflater.from(parent.getContext()).flate(R.layout.row\u布局,parent,false);
返回新的MyViewHolder(视图);
}
@凌驾
公共无效onBindViewHolder(最终MyViewHolder,最终int位置){
holder.productName.setText(movies.get(position.getTitle());
毕加索.with(context).load(movies.get(position.getPhoto()).centerCrop().resize(400400).into(holder.productImage);
holder.productImage.setImageResource(movies.get(position.getPhoto());
holder.productImage.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
listener.onSelectMovie(位置);
}
});
holder.addRemoveBt.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图v){
如果(!movies.get(position).isAddedTocart())
{
Log.v(“tej”、“tej”);
movies.get(position).setAddedTocart(true);
对数v(“t”、“t”);
holder.addRemoveBt.setText(“删除”);
Movie=movies.get(位置);
添加(电影);
对数v(“t”、“t”);
if(MainActivity的上下文实例)
{
((AddorRemoveCallbacks)上下文);
}
}
其他的
{
movies.get(position).setAddedTocart(false);
Movie=movies.get(位置);
cartmovies.remove(电影);
holder.addRemoveBt.setText(“添加”);
((AddorRemoveCallbacks)上下文).onRemoveProduct();
}
}
});
}
公共ArrayList getArrayList(){
返回电影;
}
@凌驾
public int getItemCount(){
返回电影。大小();
}
类MyViewHolder扩展了RecyclerView.ViewHolder{
图像视图产品图像;
TextView产品名称;
按钮addRemoveBt;
公共MyViewHolder(查看项目视图){
超级(项目视图);
productImage=(ImageView)itemView.findViewById(R.id.productImageView);
productName=(TextView)itemView.findViewById(R.id.productNameTv);
addRemoveBt=(按钮)itemView.findViewById(R.id.addButton);
}
}
}
MainActivity.java
package com.example.codingmounrtain.addtocartbadgecount.activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import com.example.codingmounrtain.addtocartbadgecount.Converter;
import com.example.codingmounrtain.addtocartbadgecount.ModelClasses.Movie;
import com.example.codingmounrtain.addtocartbadgecount.R;
import com.example.codingmounrtain.addtocartbadgecount.adapter.RecyclerAdapter;
import com.example.codingmounrtain.addtocartbadgecount.fragment.CartFragment;
import com.example.codingmounrtain.addtocartbadgecount.fragment.SearchFragment;
import com.example.codingmounrtain.addtocartbadgecount.interfaces.AddorRemoveCallbacks;
import java.util.ArrayList;
import java.util.Iterator;
public class MainActivity extends AppCompatActivity implements AddorRemoveCallbacks,RecyclerAdapter.Listener{
ArrayList<Movie> cartmovies = new ArrayList<>();
ArrayList<Movie> movies = new ArrayList<>();
RecyclerView mRecyclerView;
RecyclerAdapter mAdapter;
private static int cart_count=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("MovieShop");
getSupportActionBar().show();
movies.add(new Movie("Stree","A town is held in the grip of terror by tales of a mysterious woman who calls men by their name and then abducts them, leaving their clothes behind.","Rajkummar Rao","Shraddha Kapoor","Amar Kaushik",4.0f,R.drawable.stree));
movies.add(new Movie("Nun","When a young nun at a cloistered abbey in Romania takes her own life, a priest with a haunted past and a novitiate on the threshold of her final vows are sent by the Vatican to investigate. ","Demián Bichir","Taissa Farmiga","Corin Hardy",2.5f,R.drawable.nun));
movies.add(new Movie("Savita Damodar Paranjpe","The lives of a married couple are turned upside down when hard truths come to light.","Subodh Bhave","Trupti Madhukar Toradmal","Swapna Waghmare Joshi",3.5f,R.drawable.savita));
movies.add(new Movie("TC GN"," A recently retired professional is cheated of a large sum of money through a digital fraud. ","Sachin Khedekar","Iravati Harshe","Girish Jayant Joshi",3.0f,R.drawable.tcgn));
movies.add(new Movie("MI","Ethan Hunt and the IMF team join forces with CIA assassin August Walker to prevent a disaster of epic proportions.","Tom Cruise","Rebecca Ferguson","Christopher McQuarrie",4.0f,R.drawable.mi));
movies.add(new Movie("Searching","After David Kim (John Cho)'s 16-year-old daughter goes missing, a local investigation is opened and a detective is assigned to the case. ","John Cho","Debra Messing","Aneesh Chaganty",2.5f,R.drawable.searching));
movies.add(new Movie("SURYA"," Indian Telugu-language action film written and directed by Vakkantham Vamsi in his directorial debut. ","Allu Arjun","Anu Emmanuel","Vakkantham Vamsi",3.5f,R.drawable.surya));
movies.add(new Movie("TC GN"," A recently retired professional is cheated of a large sum of money through a digital fraud. ","Sachin Khedekar","Iravati Harshe","Girish Jayant Joshi",3.0f,R.drawable.tcgn));
mRecyclerView = findViewById(R.id.recyclerview);
mRecyclerView.setHasFixedSize(true);
GridLayoutManager mLayoutManager = new GridLayoutManager(this,2);
mRecyclerView.setLayoutManager(mLayoutManager);
// specify an adapter (see also next example)
mAdapter = new RecyclerAdapter(this, movies,this);
mRecyclerView.setAdapter(mAdapter);
}
@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);
MenuItem menuItem = menu.findItem(R.id.cart_action);
menuItem.setIcon(Converter.convertLayoutToImage(MainActivity.this,cart_count,R.drawable.ic_shopping_cart_white_24dp));
MenuItem menuItem2 = menu.findItem(R.id.search_action);
menuItem2.setIcon(R.drawable.ic_search_black_24dp);
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();
cartmovies = mAdapter.getArrayList();
Movie movie = null;
Iterator<Movie> iter = cartmovies.iterator();
while ( iter .hasNext() == true )
{
movie = iter.next();
Log.v("tejjjj",movie.getTitle());
}
// cartmovies.get(0).getTitle();
if(id==R.id.cart_action){
Bundle bundle = new Bundle();
bundle.putSerializable("catmovies",cartmovies);
Fragment fragment = new CartFragment();
fragment.setArguments(bundle);
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.contentLayout, fragment)
.addToBackStack("MainActivity")
.commit();
}
if(id==R.id.search_action){
Bundle bundle = new Bundle();
// bundle.putString("query", editSearch.getText().toString());
bundle.putSerializable("movies",movies);
Fragment fragment = new SearchFragment();
fragment.setArguments(bundle);
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.contentLayout, fragment)
.addToBackStack("MainActivity")
.commit();
// search(searchStr, movies);
}
return super.onOptionsItemSelected(item);
}
@Override
public void onAddProduct() {
cart_count++;
Log.v("stej",""+cart_count);
invalidateOptionsMenu();
Snackbar.make((CoordinatorLayout)findViewById(R.id.parentlayout), "Movie added to cart !!", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
@Override
public void onRemoveProduct() {
cart_count--;
Log.v("tej",""+cart_count);
invalidateOptionsMenu();
Snackbar.make((CoordinatorLayout)findViewById(R.id.parentlayout), "Movie removed from cart !!", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
@Override
public void onSelectMovie(int position) {
Movie movie = movies.get(position);
// Toast.makeText(this, "selected movie: " + movie.getTitle(), Toast.LENGTH_SHORT).show();
Intent intent = new Intent(this, DetailActivity.class);
intent.putExtra("title",movie.getTitle());
intent.putExtra("director",movie.getDirector());
intent.putExtra("actors",movie.getActors());
intent.putExtra("actresses",movie.getActresses());
intent.putExtra("info",movie.getDescription());
intent.putExtra("photo",movie.getPhoto());
intent.putExtra("rating",movie.getRating());
startActivity(intent);
}
}
package com.example.codingmounrtain.addtocartbadgecount.fragment;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import com.example.codingmounrtain.addtocartbadgecount.ModelClasses.Movie;
import com.example.codingmounrtain.addtocartbadgecount.R;
import com.example.codingmounrtain.addtocartbadgecount.activity.DetailActivity;
import com.example.codingmounrtain.addtocartbadgecount.adapter.MovieListAdapter;
import com.example.codingmounrtain.addtocartbadgecount.adapter.RecyclerAdapter;
import java.util.ArrayList;
import java.util.Iterator;
import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.Unbinder;
public class CartFragment extends Fragment implements View.OnClickListener, MovieListAdapter.Listener {
@BindView(R.id.recyclerView)
RecyclerView recyclerView;
Unbinder unbinder;
MovieListAdapter adapter;
RecyclerAdapter madapter;
ArrayList<Movie> movies = new ArrayList<>();
ArrayList<Movie> movies1 = new ArrayList<>();
public CartFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
LinearLayout layout = (LinearLayout) inflater.inflate(R.layout.fragment_cart, null);
unbinder = ButterKnife.bind(this, layout);
adapter = new MovieListAdapter(getActivity(),movies,this);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 1));
((AppCompatActivity) getActivity()).getSupportActionBar().setTitle("Movie Cart");
// movies1 =(ArrayList<Movie>) savedInstanceState.getParcelable("movies");
// buttonSearch.setOnClickListener(this);
return layout;
}
@Override
public void onResume() {
super.onResume();
getList();
}
@Override
public void onDestroyView() {
super.onDestroyView();
unbinder.unbind();
}
void getList(){
Bundle bundle = getArguments();
movies1 =(ArrayList<Movie>) bundle.getSerializable("cartmovies");
Iterator<Movie> iter = movies1.iterator();
Movie movie = null;
while(iter.hasNext() == true){
movie = iter.next();
movies.add(movie);
adapter.notifyDataSetChanged();
}
}
@Override
public void onClick(View view) {
}
@Override
public void onSelectMovie(int position) {
Movie movie = movies.get(position);
Intent intent = new Intent(getActivity(),DetailActivity.class);
intent.putExtra("title",movie.getTitle());
intent.putExtra("director",movie.getDirector());
intent.putExtra("actors",movie.getActors());
intent.putExtra("actresses",movie.getActresses());
intent.putExtra("info",movie.getDescription());
intent.putExtra("photo",movie.getPhoto());
intent.putExtra("rating",movie.getRating());
startActivity(intent);
}
}
package com.example.codingmounrtain.addtocartbadgecount.activity;
导入android.content.Intent;
导入android.os.Bundle;
导入android.support.design.widget.CoordinatorLayout;
导入android.support.design.widget.Snackbar;
导入android.support.v4.app.Fragment;
导入android.support.v7.app.AppActivity;
导入android.support.v7.widget.GridLayoutManager;
导入android.support.v7.widget.RecyclerView;
导入android.support.v7.widget.Toolbar;
导入android.util.Log;
导入android.view.Menu;
导入android.view.MenuItem;
导入com.example.codingmounrtain.addtocartbadgecount.Converter;
导入com.example.codingmounrtain.addtocartbadgecount.ModelClasses.Movie;
导入com.example.codingmounrtain.addtocartbadgecount.R;
导入com.example.codingmounrtain.addtocartbadgecount.adapter.RecyclerAdapter;
导入com.example.codingmounrtain.addtocartbadgecount.fragment.CartFragment;
导入com.example.codingmounrtain.addtocartbadgecount.fragment.SearchFragment;
导入com.example.codingmounrtain.addtocartbackcount.interfaces.AddorRemoveCallbacks;
导入java.util.ArrayList;
导入java.util.Iterator;
公共类MainActivity扩展AppCompatActivity实现AddorRemoveCallbacks、RecyclerAdapter.Listener{
ArrayList=newArrayList();
ArrayList电影=新建ArrayList();
回收视图mRecyclerView;
回收器适配器;
私有静态int cart_计数=0;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar Toolbar=(Toolbar)findViewById(R.id.Toolbar);
设置支持操作栏(工具栏);
getSupportActionBar().setTitle(“MovieShop”);
getSupportActionBar().show();
电影。添加(新电影(“
public class MyModel implements Serializable {
private ArrayList<Data> datas;
public MyModel(ArrayList<Data> datas) {
this.datas = datas
}
}
Bundle bundle = new Bundle();
bundle.putSerializable();
myFragment.setArguments(bundle);
public ArrayList<Object> getArrayList() {
return yourArrayList;
}
getSupportFragmentManager().beginTransaction()
.add(containerId, YourFragment.getInstance(yourArrayList), tag)
.commitAllowingStateLoss();
public static YourFragment getInstance( ArrayList<Object> yourArrayList) {
Bundle bundle = new Bundle();
bundle.putParcelableArrayList(Constants.YOUR_LIST,yourArrayList);
YourFragment yourFragment = new YourFragment();
yourFragment.setArguments(bundle);
return yourFragment;
}
if (getArguments()!=null && getArguments().containsKey(Constants.YOUR_LIST) && getArguments().getParcelableArrayList(Constants.YOUR_LIST) != null){
ArrayList<Object> yourlist = getArguments().getParcelableArrayList(Constants.YOUR_LIST);
}