custom checkbox difficulty in android

问题

how to modify this imageCheckBoxAdapter code in order to maintain status of checkBox when scrolled(that is all the checkboxes which are checked should remain checked even after scrolling. Also the checked variables need to be stored in an array)?

class imageCheckBoxAdapter extends ArrayAdapter<String>
{
private final Context context;
private final ArrayList<String> values;
private final Map< String, SmbFile> obj;
static ArrayList<Boolean> checks=new ArrayList<Boolean>();
public imageCheckBoxAdapter(Context context,ArrayList<String> values,Map< String, SmbFile>obj) 
{
    super(context, R.layout.row_checkbox, values);
    this.context = context;
    this.values = values;
    this.obj=obj;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View rowView = inflater.inflate(R.layout.row_checkbox, parent, false);
    TextView textView = (TextView) rowView.findViewById(R.id.text1_check);
    textView.setText(values.get(position));
    ImageView imageView = (ImageView) rowView.findViewById(R.id.icon_image_check);
    try
    {
        if((obj.get(values.get(position)).isFile()))
        {
            imageView.setImageResource(R.drawable.view_file_icon);
        }
        else
        {
            imageView.setImageResource(R.drawable.view_folder_icon);
        }
    }
    catch (SmbException e) 
    {
        Toast.makeText(context,"Network error",Toast.LENGTH_SHORT).show();
        Log.d("id1", "error1");
        e.printStackTrace();
    }
    return rowView;
}
}

row_checkbox.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:padding="5dp" >
    <CheckBox
    android:id="@+id/checkBox1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:checked="false" />
 <ImageView
    android:id="@+id/icon_image_check"
    android:layout_width="50px"
    android:layout_height="50px"
    android:layout_marginLeft="5px"
    android:layout_marginRight="20px"
    android:layout_marginTop="5px"
    android:src="@drawable/view_file_icon" >
    </ImageView>
 <TextView
    android:id="@+id/text1_check"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@+id/label"
    android:textSize="30px" 
    android:typeface="sans">
    </TextView> 
</LinearLayout>

回答1:

class imageCheckBoxAdapter extends ArrayAdapter<String> implements View.onClickListener
{
    private final Context context;
    private final ArrayList<String> values;
    private final Map< String, SmbFile> obj;
    private ArrayList<Boolean> checks=new ArrayList<Boolean>();

    public imageCheckBoxAdapter(Context context,ArrayList<String> values,Map< String, SmbFile>obj) 
    {
        super(context, R.layout.row_checkbox, values);
        this.context = context;
        this.values = values;
        this.obj=obj;

        for (int i = 0; i < values.size(); i++) {
            checks.add(i, false);
        }
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View rowView = inflater.inflate(R.layout.row_checkbox, parent, false);
        TextView textView = (TextView) rowView.findViewById(R.id.text1_check);
        CheckBox chk = (CheckBox) rowView.findViewById(R.id.checkBox1);
        textView.setText(values.get(position));
        ImageView imageView = (ImageView) rowView.findViewById(R.id.icon_image_check);
        try
        {
            if((obj.get(values.get(position)).isFile()))
            {
                imageView.setImageResource(R.drawable.view_file_icon);
            }
            else
            {
                imageView.setImageResource(R.drawable.view_folder_icon);
            }
        }
        catch (SmbException e) 
        {
            Toast.makeText(context,"Network error",Toast.LENGTH_SHORT).show();
            Log.d("id1", "error1");
            e.printStackTrace();
        }

        chk.setTag(Integer.valueOf(position));

        // Set a listener for the checkbox
        chk.setOnClickListener(this);

        //Sets the state of CB, since we have the list of checked CB
        chk.setChecked(checks.get(position));

        return rowView;
    }

    @Override
    public void onClick(View view) {
        Integer index = (Integer)view.getTag();
        boolean state = checks.get(index.intValue());

        checks.set(index.intValue(), !state);
    }
}

回答2:

I think your need to store value in an array. For each checkBox, you set a changeListener to store the checkBox associated.

回答3:

I recently read, not sure where already, a similar case someone asked about.

If I understand correctly, this may be because the CheckBox control is not databound in the DataRepeaterItem, and when scrolling the checkboxes lose their state.

You can try using Viewstate to maintain checked value. I'll try finding that post, it seemed informative.

回答4:

I think you can save the position of the checkbox in the list by using the View.setTag method make a reference of your checkbox in the getView like this:

CheckBox chk = (CheckBox) rowView.findViewById(R.id.checkBox1);

Since CheckBoxes are indirect subclasses of View, it also has an attribute View.setTag like this:

chk.setTag(Integer.valueOf(position));

Then set an OnCheckedChangeListener to your chk like:

chk.setOnCheckedChangeListener(new OnCheckedChangeListener {
    public void onCheckedChanged(CompoundButton buttonView, boolean state) {
           Integer int = (Integer)buttonView.getTag();

           checks.set(int.intValue(), !boolean)
    }
});

Since the boolean arraylist size is same to the values size, the specified position corresponds the exact location of the checkbox

Then add this snippet to your getView method:

if (checks.get(position)) {
  chk.setChecked(checks.get(position));
  // do some stuff if wanted..
} else {
  chk.setChecked(checks.get(position));
  // do some stuff if wanted..
}

We did the snippet because when listview is scrolled upward or downward getView is called for the unseen row item. And to update the row item if already checked or not.

来源：https://stackoverflow.com/questions/10214271/custom-checkbox-difficulty-in-android