Dai un'occhiata a questo codice di esempio che dimostra la funzionalità. È un RecyclerView
che chiama notifyItemChanged(position, payload)
quando si fa clic sull'elemento nella posizione position
. È possibile verificare che onBindViewHolder(holder, position, payload)
sia stato chiamato cercando l'istruzione logcat.
Assicurarsi che si sta utilizzando almeno la versione 23.1.1
delle librerie di supporto, in questo modo:
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.android.support:recyclerview-v7:23.1.1'
compile 'com.android.support:cardview-v7:23.1.1'
}
HelloActivity.java
package com.formagrid.hellotest;
import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.CardView;
import android.support.v7.widget.DefaultItemAnimator;
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.TextView;
import java.util.List;
public class HelloActivity extends Activity {
private RecyclerView mRecyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
mRecyclerView.setAdapter(new HelloAdapter());
DefaultItemAnimator animator = new DefaultItemAnimator() {
@Override
public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder) {
return true;
}
};
mRecyclerView.setItemAnimator(animator);
}
private static class HelloAdapter extends RecyclerView.Adapter<HelloAdapter.HelloViewHolder> {
public class HelloViewHolder extends RecyclerView.ViewHolder {
public TextView textView;
public HelloViewHolder(CardView cardView) {
super(cardView);
textView = (TextView) cardView.findViewById(R.id.text_view);
}
}
@Override
public HelloViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
CardView cardView = (CardView) LayoutInflater.from(parent.getContext()).inflate(
R.layout.card_item, parent, false);
return new HelloViewHolder(cardView);
}
@Override
public void onBindViewHolder(HelloViewHolder holder, int position) {
bind(holder);
}
@Override
public void onBindViewHolder(HelloViewHolder holder, int position, List<Object> payload) {
Log.d("butt", "payload " + payload.toString());
bind(holder);
}
@Override
public int getItemCount() {
return 20;
}
private void bind(final HelloViewHolder holder) {
holder.textView.setText("item " + holder.getAdapterPosition());
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final int position = holder.getAdapterPosition();
Log.d("butt", "click " + position);
HelloAdapter.this.notifyItemChanged(position, "payload " + position);
}
});
}
}
}
activity_main.xml
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".HelloActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
card_item. xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="100dip"
android:layout_margin="5dip"
card_view:cardElevation="5dip">
<TextView
android:id="@+id/text_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.v7.widget.CardView>
fonte
2015-11-28 07:16:38
Ho appena testato il codice. C'è qualcosa di inutile nel mio test: il basic onBind (senza payload) non viene mai chiamato. Adesso perché? Ho appena chiamato notifyItemRangeChanged (index, mArrayList.size()); oppure notifyItemInserted (i); – Cocorico
ama il tag di registro immaturo +1 – styler1972