<ListView
android:id="@+id/MainListView"
android:layout_width="match_parent"
android:layout_height="match_parent" />Requiere de un Adapter para especificar como se mostrarán los datos.
listView = findViewById(R.id.MainListView);
List<String> nameList = new ArrayList<String>();
nameList.add("Alan");
nameList.add("Andy");
nameList.add("Angel");
nameList.add("Eduardo");
nameList.add("Oscar");
ArrayAdapter<String> namesAdapter =
new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,nameList);
listView.setAdapter(namesAdapter);
Implementar onItemClick:
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
String name = nameList.get(position);
Toast.makeText(MainActivity.this,name,Toast.LENGTH_SHORT).show();
}
});Creamos una clase que herede de BaseAdapter, implementamos los métodos de la interface y en el método GetView llena una vista con un layout y se asignan los datos a la vista.
public class MyAdapter extends BaseAdapter {
private Context acitivityContext;
private int layoutId;
private List<String> nameList;
public MyAdapter(Context context,int layout, List<String> names)
{
this.acitivityContext = context;
this.layoutId = layout;
this.nameList = names;
}
@Override
public int getCount() {
return this.nameList.size();
}
@Override
public Object getItem(int position) {
return this.nameList.get(position);
}
@Override
public long getItemId(int id) {
return id;
}
@Override
public View getView(int position, View convertView, ViewGroup viewGroup) {
//Fill view with item layout
LayoutInflater layoutInflater = LayoutInflater.from(this.acitivityContext);
View viewInflate = layoutInflater.inflate(R.layout.item_layout,null);
//Set text by position to TextView
String name = nameList.get(position);
TextView nameTextView = viewInflate.findViewById(R.id.ItemTextView);
nameTextView.setText(name);
return viewInflate;
}
}<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#EFF0F1"
android:orientation="horizontal"
android:padding="20dp">
<TextView
android:id="@+id/ItemTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_weight="1"
android:textSize="20dp"
android:textStyle="bold" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="20dp"
android:src="@android:drawable/star_big_on" />
</LinearLayout> @Override
public View getView(int position, View convertView, ViewGroup viewGroup) {
//View holder pattern
ViewHolder holder;
//First time renderer is null
if(convertView == null){
//Fill view with item layout
LayoutInflater layoutInflater = LayoutInflater.from(this.acitivityContext);
convertView = layoutInflater.inflate(this.layoutId,null);
holder = new ViewHolder();
//Save reference in holder
holder.nameTextView = convertView.findViewById(R.id.ItemTextView);
convertView.setTag(holder);
}else{
//For example when scroll is up, recover reference
holder = (ViewHolder) convertView.getTag();
}
//Set text by position to TextView
String name = nameList.get(position);
holder.nameTextView.setText(name);
return convertView;
}
private static class ViewHolder {
private TextView nameTextView;
}Un GridView soporta adaptadores igual que un ListView, así que sería la misma forma de implementarlo
Se puede aplicar el context menu para cualquier elemento, en este ejemplo se realiza en un GridView
/**
* Set add layout to menu
* @param menu Menu
* @return is success
*/
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.action_bar_menu,menu);
return true;
}
/**
* Add item to name list
* @param item Menu item
* @return Is success
*/
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.addItem:
this.nameList.add("Added "+(++counter));
//Notify to adapter that data source changed
this.myAdapter.notifyDataSetChanged();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/**
* Set remove layout to menu
* @param menu Context menu
* @param v View
* @param menuInfo menu info
*/
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu,v,menuInfo);
//Set title
AdapterView.AdapterContextMenuInfo info =
(AdapterView.AdapterContextMenuInfo)menuInfo;
menu.setHeaderTitle(this.nameList.get(info.position));
//Set layout
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.context_menu,menu);
}
/**
* Remove name from list
* @param item Menu item
* @return Is success
*/
@Override
public boolean onContextItemSelected(MenuItem item) {
//Get item info
AdapterView.AdapterContextMenuInfo info =
(AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
switch (item.getItemId()){
case R.id.delete_item:
this.nameList.remove(info.position);
//Notify to adapter that data source changed
this.myAdapter.notifyDataSetChanged();
return true;
default:
return super.onContextItemSelected(item);
}
}NOTA: Es importante registrar la vista que tendra el Context Menu en el método OnCreate() de la siguiente forma registerForContextMenu(this.gridView);.
