Setting ListView item checked from Adapter
I have a ListView which displays 2 kinds of items. One of these kinds contains CheckedTextView. As an adapter I'm using custom adapter extending ArrayAdapter with data structure containing information about checked/unchecked states inside.
Some of the items are marked as selected (in my data structure) so of course I'd like the checkboxes to be marked when the ListView is created. I tried to do it on getView() method in adapter with CheckedTextView's setChecked() method but it doesn't work. I found information that it should be done on a ListView level with setItemChecked() and it does work but it doesn't make sense to me because to make it work I would have to loop all items in activity's onCreate() calling setItemChecked() for those selected. The list of items may be very long with only a few of them selected so it's a waste.
Why calling setChecked() in getView() isn't working? Is there a better way of doing this (I'm an Android newbie).
Below you have my checked item layout and the adapter.
Layout:
<?xml version="1.0" encoding="utf-8"?>
<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/text1"
android:layout_width="fill_parent"
android:layout_height="?android:attr/listPreferredItemHeight"
android:gravity="center_vertical"
android:textAppearance="@style/listViewItemText"
android:checkMark="?android:attr/listChoiceIndicatorMultiple"
android:paddingLeft="6dp"
android:paddingRight="6dp"
/>
Adapter:
package com.melog.re.droid.search;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.os.Parcel;
import android.os.Parcelable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckedTextView;
import android.widget.TextView;
import com.melog.re.droid.core.R;
import com.melog.re.droid.search.MultiCriterionValue.MultiCriterionSingleValue;
import com.melog.re.droid.search.MultiListAdapter.MultiChoiceItem;
public class MultiListAdapter extends ArrayAdapter<MultiChoiceItem> {
private static final int VIEW_TYPES_COUNT = 2;
public static final int VIEW_TYPE_GROUP = 0;
public static final int VIEW_TYPE_ITEM = 1;
private LayoutInflater mInflater;
public MultiListAdapter(Context context, int textViewResourceId, List<MultiChoiceItem> objects) {
super(context, textViewResourceId, objects);
mInflater = LayoutInflater.from(context);
}
@Override
public int getItemViewType(int position) {
MultiChoiceItem item = getItem(position);
return (item.children.size() == 0) ? VIEW_TYPE_ITEM : VIEW_TYPE_GROUP;
}
@Override
public int getViewTypeCount() {
return VIEW_TYPES_COUNT;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO: optymalizacja ViewHolder
MultiChoiceItem item = getItem(position);
int viewType = getItemViewType(position);
switch (viewType) {
case VIEW_TYPE_GROUP:
if (convertView == null) {
convertView = mInflater.inflate(R.layout.multi_choice_group_item, parent, false);
}
TextView groupLabel = (TextView) convertView.findViewById(android.R.id.text1);
groupLabel.setText(item.toString());
break;
case VIEW_TYPE_ITEM:
if (convertView == null) {
convertView = mInflater.inflate(R.layout.multi_choice_child_item, parent, false);
}
CheckedTextView itemLabel = (CheckedTextView) convertView.findViewById(android.R.id.text1);
itemLabel.setText(item.toString());
itemLabel.setChecked(item.selected);
break;
}
return convertView;
}
public static class MultiChoiceItem implements Parcelable {
public static final int CONTENTS_DESCR = 1;
public String label;
public String value;
public boolean selected = false;
public ArrayList<MultiChoiceItem> children = new ArrayList<MultiChoiceItem>();
public MultiChoiceItem(String l, String v, boolean sel) {
label = l;
value = v;
selected = sel;
}
public MultiChoiceItem(MultiCriterionSingleValue v) {
label = v.toString();
value = v.value;
}
public MultiChoiceItem(Parcel in) {
label = in.readString();
value = in.readString();
selected = (in.readInt() == 1);
}
@Override
public String toString() {
return label;
}
@Override
public int describeContents() {
return CONTENTS_DESCR;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(label);
dest.writeString(value);
dest.writeInt(selected ? 1 : 0);
}
public static final Parcelable.Creator<MultiChoiceItem> CREATOR = new Parcelable.Creator<MultiChoiceItem>() {
public MultiChoiceItem createFromParcel(Parcel in) {
return new MultiChoiceItem(in);
}
public MultiChoiceItem[] newArray(int size) {
return new MultiChoiceItem[size];
}
};
}
}
And a piece of acti开发者_开发百科vity's onCreate()
...
mAdapter = new MultiListAdapter(this, R.id.head, mItems);
setListAdapter(mAdapter);
final ListView listView = getListView();
listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
listView.setItemsCanFocus(false);
...
Edit:
Until finding a better solution I implemented the checking in the Activity:
...
int len = mListView.getCount();
for (int i = 0; i < len; i++) {
if (((MultiChoiceItem) mListView.getItemAtPosition(i)).selected) {
mListView.setItemChecked(i, true);
}
}
...
I thought that performance will be the only potential problem but I found another one - much more serious. The list has text filter enabled (mListView.setTextFilterEnabled(true)). Here's the failure scenario:
- I'm opening new list
- Im checking let's say 2-nd item
- I start typing to filter some items
- when the filtering is done, the 2-nd item is still checked even though it's not the one I checked
I assume that setItemChecked() marks a fixed position on the list checked while I need something that will mark the Item held on ths position - keeping the state even when the position on the list changes.
While performance issue could be (to some point) ignored - this new problem is really blocking me, so I would really appreciate any help with it.
If you use ListView.CHOICE_MODE_MULTIPLE
or CHOICE_MODE_SINGLE
the check states of the items will be overridden by ListView after getView
is being called. You have to use the following construct:
@Override
public View getView(int position, View convertView, ViewGroup parent) {
((ListView)parent).setItemChecked(position, true);
}
Another possiblity is to use ListView.CHOICE_MODE_NONE
and manage the check states by yourself.
Check out the steps First in item xml make the changes add single line in check box
`android:onClick="chatWithFriend"`
so when the click on cheackbox then create the one method in activity name
public void chatWithFriend(View view){}
here you will get the view of check box,
Now add the line in getView before return convert view
holder.checkbox.setTag(position);
Now u will get the position of the check box
I hope this will help you.
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