当我单击循环视图的每个项目时，为什么此应用程序无法正常工作项目位置的Toast会出现，但是当我单击每个项目（cardview）以打开新的活动应用程序崩溃时。我不知道出了什么问题。
GalleryFragment.java
package com.example.kiran.cr7;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.CardView;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
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.AdapterView;
import android.widget.GridView;
import android.widget.Toast;
import java.util.ArrayList;
/** * A simple {@link Fragment} subclass. */ public class GalleryFragment extends Fragment implements Adapter.OnCardClickListner {
public GalleryFragment() {
// Required empty public constructor
}
private RecyclerView mrecycleview;
private CardView mcardview;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_gallery, container, false);
mrecycleview = (RecyclerView)view.findViewById(R.id.recycle_view);
mcardview = (CardView)view.findViewById(R.id.card_view);
//improve performance
mrecycleview.setHasFixedSize(true);
LinearLayoutManager manager = new LinearLayoutManager(view.getContext());
mrecycleview.setLayoutManager(manager);
ArrayList<Item> itemlist = dummies();
//set adapter // Adapter adapter = new Adapter(view.getContext(),itemlist); // mrecycleview.setAdapter(adapter); // adapter.setOnCardClickListner(this);
Adapter adapter = new Adapter(view.getContext(),itemlist);
mrecycleview.setAdapter(adapter);
adapter.setOnCardClickListner(this);
return view;
}
private ArrayList<Item> dummies() {
ArrayList<Item> list = new ArrayList<>();
for (int i = 0; i < 6; i++) {
if (i == 0) {
Item item = new Item();
item.id = i;
item.text = "RonaldoPhoto" + (i);
item.img = "http://wallpapercave.com/wp/sIggTrG.jpg";
list.add(item);
} else if (i == 1) {
Item item = new Item();
item.id = i;
item.text = "RonaldoPhoto" + (i);
item.img = "http://i2.wp.com/www.footballwood.com/wp-content/uploads/2015/01/Ronaldo-Best-Wallpapers.jpg";
list.add(item);
} else if (i == 2) {
Item item = new Item();
item.id = i;
item.text = "RonaldoPhoto" + (i);
item.img = "http://www.magazinefuse.com/wp-content/uploads/2015/09/7-i476725-1024x640.jpg";
list.add(item);
} else if (i == 3) {
Item item = new Item();
item.id = i;
item.text = "RonaldoPhoto" + (i);
item.img = "https://i.ytimg.com/vi/SwHv6xGGBBQ/maxresdefault.jpg";
list.add(item);
}else if (i == 4) {
Item item = new Item();
item.id = i;
item.text = "RonaldoPhoto" + (i);
item.img = "https://i.ytimg.com/vi/WrCfkR4Qcns/maxresdefault.jpg";
list.add(item);
}
else if (i == 5) {
Item item = new Item();
item.id = i;
item.text = "RonaldoPhoto" + (i);
item.img = "http://images.latinpost.com/data/images/full/101477/cristiano-ronaldo-real-madrid.jpg";
list.add(item);
}
}
return list;
}
@Override
public void OnCardClicked(View view, int position) {
Log.d("OnClick", "Card Position" + position);
Toast.makeText(getContext(),"click"+position,Toast.LENGTH_SHORT).show();
Intent in= new Intent(view.getContext(),Detail.class);
in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(in);
} }
Adapter.java
package com.example.kiran.cr7;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.widget.CardView;
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 android.widget.Toast;
import com.squareup.picasso.Picasso;
import java.util.ArrayList;
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder>{
private RecyclerView mRecyclerView;
private Context context;
private ArrayList<Item> itemlist;
OnCardClickListner onCardClickListner;
public Adapter(Context context, ArrayList<Item> itemlist){
this.context = context;
this.itemlist = itemlist;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.from(parent.getContext()).inflate(R.layout.cardview,parent,false);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recycle_view);
ViewHolder viewholder = new ViewHolder(view);
return viewholder;
}
//bind views with data
@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
final Item item = itemlist.get(position);
//get element form your dataset at this position
//replace the contents of the view with that element
Picasso.with(context)
.load(item.img)
.placeholder(R.drawable.fern)
.error(android.R.drawable.stat_notify_error)
.into(holder.cardimage);
holder.cardtext.setText(item.text);
holder.card_view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onCardClickListner.OnCardClicked(v,position);
Intent in = new Intent(v.getContext(), Detail.class);
in.putExtra("item",item);
in.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//context.startActivity(in);
}
});
}
@Override
public int getItemCount() {
if(itemlist != null){
return itemlist.size();
}
return 0;
}
//provide the reference to the views for each data item
//ViewHolder class
//since it is static it uses only single memory so protect memory leak : a design pattern for android
public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public CardView card_view;
public TextView cardtext;
public ImageView cardimage;
//connects which view belongs to which layout
public ViewHolder(View itemView) {
super(itemView);
card_view = (CardView)itemView.findViewById(R.id.card_view);
cardtext = (TextView)itemView.findViewById(R.id.cardtext);
cardimage = (ImageView)itemView.findViewById(R.id.cardimage);
}
@Override
public void onClick(View view) {
}
}
public interface OnCardClickListner {
void OnCardClicked(View view, int position);
}
public void setOnCardClickListner(OnCardClickListner onCardClickListner) {
this.onCardClickListner = onCardClickListner;
}
}
详细
package com.example.kiran.cr7;
import android.app.DownloadManager; import android.content.Context; import android.net.ConnectivityManager; import android.net.NetworkInfo; import android.net.Uri; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.View; import android.widget.ImageView; import android.widget.Toast;
import com.squareup.picasso.Picasso;
import java.util.ArrayList;
public class Detail extends AppCompatActivity implements Adapter.OnCardClickListner {
private ImageView detailimage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail);
detailimage = (ImageView)findViewById(R.id.detailimage);
}
@Override
public void OnCardClicked(View view, int position) {
Log.d("OnClick", "Card Position" + position);
if(getIntent().getSerializableExtra("item") != null){
Item i = (Item)getIntent().getSerializableExtra("item");
Picasso.with(this)
.load(i.img)
.placeholder(R.drawable.fern)
.error(android.R.drawable.stat_notify_error)
.into(detailimage);
}
} }
答案 0 :(得分：0)
您无需在detail.java活动中使用OnCardClicked。使用serializable从一个活动发送数据。使用OnCardClicked.onBindViewHolder将数据从一个活动发送到另一个活动。
package com.example.kiran.cr7;
import android.app.DownloadManager;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import com.squareup.picasso.Picasso;
public class Test extends Activity {
private ImageView detailimage;
private Button download;
DownloadManager downloadManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
download = (Button) findViewById(R.id.Download);
detailimage = (ImageView) findViewById(R.id.detailimage);
final Animation animAlpha = AnimationUtils.loadAnimation(this,R.anim.anim_alpha);
if (getIntent().getSerializableExtra("item") != null) {
final Item i = (Item) getIntent().getSerializableExtra("item");
Picasso.with(this)
.load(i.img)
.resize(500,600)
.placeholder(R.drawable.fern)
.error(android.R.drawable.stat_notify_error)
.into(detailimage);
ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected()) {
//Toast.makeText(Test.this, "Network Connection available", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(Test.this, "No Network Connection", Toast.LENGTH_LONG).show();
}
download.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
view.startAnimation(animAlpha);
downloadManager =(DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse(i.img);
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
Long reference = downloadManager.enqueue(request);
}
});
}
}
}