我有一个带有多个复选框的 ListView（每个列表项一个）。创建包含来自选定复选框的信息的数组的最佳方法是什么。
例如，这是一个列表。
Item 1 "Ham" Checked
Item 2 "Turkey" NotChecked
Item 3 "Bread" Checked
我想创建一个包含“火腿”和“火鸡”的数组
问问题
4146 次
2 回答
2
您可以创建一个 ArrayList，然后用户检查的任何项目将它们添加到 arraylist。
下面的代码片段完全符合您的要求。
package com.windrealm.android;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class PlanetsActivity extends Activity
{
private ListView mainListView;
private Planet[] planets;
private ArrayAdapter<Planet> listAdapter;
private Button check;
private Context context;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
context = PlanetsActivity.this;
check = (Button) findViewById(R.id.check);
// Find the ListView resource.
mainListView = (ListView) findViewById(R.id.mainListView);
// When item is tapped, toggle checked properties of CheckBox and
// Planet.
mainListView
.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
@Override
public void onItemClick(AdapterView<?> parent, View item,
int position, long id)
{
Planet planet = listAdapter.getItem(position);
planet.toggleChecked();
PlanetViewHolder viewHolder = (PlanetViewHolder) item
.getTag();
viewHolder.getCheckBox().setChecked(planet.isChecked());
}
});
// Create and populate planets.
planets = (Planet[]) getLastNonConfigurationInstance();
if (planets == null)
{
planets = new Planet[]
{ new Planet("Mercury"), new Planet("Venus"), new Planet("Earth"),
new Planet("Mars"), new Planet("Jupiter"),
new Planet("Saturn"), new Planet("Uranus"),
new Planet("Neptune"), new Planet("Ceres"),
new Planet("Pluto"), new Planet("Haumea"),
new Planet("Makemake"), new Planet("Eris") };
}
ArrayList<Planet> planetList = new ArrayList<Planet>();
planetList.addAll(Arrays.asList(planets));
// Set our custom array adapter as the ListView's adapter.
listAdapter = new PlanetArrayAdapter(this, planetList);
mainListView.setAdapter(listAdapter);
check.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View view)
{
for (int i = 0; i < listAdapter.getCount(); i++)
{
Planet planet = listAdapter.getItem(i);
if (planet.isChecked())
{
//Add this item in ArrayList
Toast.makeText(context,
planet.getName() + " is Checked!!",
Toast.LENGTH_SHORT).show();
}
}
}
});
}
/** Holds planet data. */
private static class Planet
{
private String name = "";
private boolean checked = false;
public Planet()
{
}
public Planet(String name)
{
this.name = name;
}
public Planet(String name, boolean checked)
{
this.name = name;
this.checked = checked;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public boolean isChecked()
{
return checked;
}
public void setChecked(boolean checked)
{
this.checked = checked;
}
public String toString()
{
return name;
}
public void toggleChecked()
{
checked = !checked;
}
}
/** Holds child views for one row. */
private static class PlanetViewHolder
{
private CheckBox checkBox;
private TextView textView;
public PlanetViewHolder()
{
}
public PlanetViewHolder(TextView textView, CheckBox checkBox)
{
this.checkBox = checkBox;
this.textView = textView;
}
public CheckBox getCheckBox()
{
return checkBox;
}
public void setCheckBox(CheckBox checkBox)
{
this.checkBox = checkBox;
}
public TextView getTextView()
{
return textView;
}
public void setTextView(TextView textView)
{
this.textView = textView;
}
}
/** Custom adapter for displaying an array of Planet objects. */
private static class PlanetArrayAdapter extends ArrayAdapter<Planet>
{
private LayoutInflater inflater;
public PlanetArrayAdapter(Context context, List<Planet> planetList)
{
super(context, R.layout.simplerow, R.id.rowTextView, planetList);
// Cache the LayoutInflate to avoid asking for a new one each time.
inflater = LayoutInflater.from(context);
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
// Planet to display
Planet planet = (Planet) this.getItem(position);
// The child views in each row.
CheckBox checkBox;
TextView textView;
// Create a new row view
if (convertView == null)
{
convertView = inflater.inflate(R.layout.simplerow, null);
// Find the child views.
textView = (TextView) convertView
.findViewById(R.id.rowTextView);
checkBox = (CheckBox) convertView.findViewById(R.id.CheckBox01);
// Optimization: Tag the row with it's child views, so we don't
// have to
// call findViewById() later when we reuse the row.
convertView.setTag(new PlanetViewHolder(textView, checkBox));
// If CheckBox is toggled, update the planet it is tagged with.
checkBox.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
CheckBox cb = (CheckBox) v;
Planet planet = (Planet) cb.getTag();
planet.setChecked(cb.isChecked());
}
});
}
// Reuse existing row view
else
{
// Because we use a ViewHolder, we avoid having to call
// findViewById().
PlanetViewHolder viewHolder = (PlanetViewHolder) convertView
.getTag();
checkBox = viewHolder.getCheckBox();
textView = viewHolder.getTextView();
}
// Tag the CheckBox with the Planet it is displaying, so that we can
// access the planet in onClick() when the CheckBox is toggled.
checkBox.setTag(planet);
// Display planet data
checkBox.setChecked(planet.isChecked());
textView.setText(planet.getName());
return convertView;
}
}
public Object onRetainNonConfigurationInstance()
{
return planets;
}
}
于 2012-06-16T20:43:09.337 回答
2
如果您将 ListView 的内置复选框方法与 setChoiceMode() 一起使用，则只需调用 getCheckedItemIds ()或getCheckedItemPositions()。
public class Example extends Activity implements OnClickListener {
ListView mListView;
String[] array = new String[] {"Ham", "Turkey", "Bread"};
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_checked, array);
mListView = (ListView) findViewById(R.id.list);
mListView.setAdapter(adapter);
mListView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(this);
}
public void onClick(View view) {
SparseBooleanArray positions = mListView.getCheckedItemPositions();
int size = positions.size();
for(int index = 0; index < size; index++) {
Log.v("Example", "Checked: " + array[positions.keyAt(index)]);
}
}
}
如果适配器绑定到游标，那么这将变得更加实用。
于 2012-06-16T20:44:37.710 回答