Checkbox unchecked when I scroll listview on Andro

问题:

I am new to Android development. I created a listview with a textbox and checkbox.

When I check the checkbox and scroll it down to check some other items in the list view, the older ones are unchecked.

How do I avoid this problem in a listview? Please guide me with my code.

Here is the code:

main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <TextView
        android:id="@+id/TextView01"
        android:layout_height="wrap_content"
        android:text="List of items"
        android:textStyle="normal|bold"
        android:gravity="center_vertical|center_horizontal"
        android:layout_width="fill_parent"/>

    <ListView
        android:id="@+id/ListView01"
        android:layout_height="250px"
        android:layout_width="fill_parent"/>

    <Button
        android:text="Save"
        android:id="@+id/btnSave"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

---

This is the XML page I used to create dynamic list row:

listview.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="wrap_content"
    android:gravity="left|center"
    android:layout_width="wrap_content"
    android:paddingBottom="5px"
    android:paddingTop="5px"
    android:paddingLeft="5px">

    <TextView
        android:id="@+id/TextView01"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textColor="#FFFF00"
        android:text="hi"/>

    <TextView
        android:text="hello"
        android:id="@+id/TextView02"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10px"
        android:textColor="#0099CC"/>

    <EditText
        android:id="@+id/txtbox"
        android:layout_width="120px"
        android:layout_height="wrap_content"
        android:textSize="12sp"
        android:layout_x="211px"
        android:layout_y="13px"/>

    <CheckBox
        android:id="@+id/chkbox1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

---

This is my activity class.

CustomListViewActivity.java:

public class CustomListViewActivity extends Activity {

    ListView lstView;
    static Context mContext;
    Button btnSave;

    private static class EfficientAdapter extends BaseAdapter {
        private LayoutInflater mInflater;

        public EfficientAdapter(Context context) {
            mInflater = LayoutInflater.from(context);

        }

        public int getCount() {
            return country.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            final ViewHolder holder;
            if (convertView == null) {
                convertView = mInflater.inflate(R.layout.listview, parent,
                        false);
                holder = new ViewHolder();
                holder.text = (TextView) convertView
                        .findViewById(R.id.TextView01);
                holder.text2 = (TextView) convertView
                        .findViewById(R.id.TextView02);
                holder.txt = (EditText) convertView.findViewById(R.id.txtbox);
                holder.cbox = (CheckBox) convertView.findViewById(R.id.chkbox1);

                convertView.setTag(holder);
            }
            else {
                holder = (ViewHolder) convertView.getTag();
            }

            holder.text.setText(curr[position]);
            holder.text2.setText(country[position]);
            holder.txt.setText("");
            holder.cbox.setChecked(false);

            return convertView;
        }

        public class ViewHolder {
            TextView text;
            TextView text2;
            EditText txt;
            CheckBox cbox;
        }
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        lstView = (ListView) findViewById(R.id.ListView01);
        lstView.setAdapter(new EfficientAdapter(this));
        btnSave = (Button)findViewById(R.id.btnSave);
        mContext = this;

        btnSave.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // I want to print the text which is in the listview one by one.
                // Later I will insert it in the database.
                //
                //            Toast.makeText(getBaseContext(), "EditText Value, checkbox value and other values", Toast.LENGTH_SHORT).show();
                for (int i = 0; i < lstView.getCount(); i++) {
                    View listOrderView;
                    listOrderView = lstView.getChildAt(i);
                    try{
                        EditText txtAmt = (EditText)listOrderView.findViewById(R.id.txtbox);
                        CheckBox cbValue = (CheckBox)listOrderView.findViewById(R.id.chkbox1);
                        if(cbValue.isChecked()== true){
                            String amt = txtAmt.getText().toString();
                            Toast.makeText(getBaseContext(), "Amount is :"+amt, Toast.LENGTH_SHORT).show();
                        }

                    }
                    catch (Exception e) {
                        // TODO: handle exception
                    }
                }

            }
        });
    }

    private static final String[] country = { "item1", "item2", "item3",
        "item4", "item5", "item6","item7", "item8", "item9",
        "item10", "item11", "item12" };

    private static final String[] curr = { "1", "2", "3", "4", "5", "6","7", "8", "9", "10", "11", "12" };
}

Please help me to solve this problem.

I have referred to this problem in many places. But I could not get proper answer to solve this problem.

Please provide me the code to avoid unchecking the checkbox while scrolling up and down.

回答1:

In the custom listview adapter call setChecked after calling setOnCheckedChangeListener.

This way you sever the link to the old listener from the recycled view.

回答2:

You can use the following adapter code to run a checkbox perfectly in a ListView.

A detailed demo is here: Listview With Checkbox Android

See the detailed demo link for deep information. It also shows how to send checked information to the next activity.

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;


public class CustomAdapter  extends BaseAdapter {

    private Context context;
    public static ArrayList<Model> modelArrayList;

    public CustomAdapter(Context context, ArrayList<Model> modelArrayList) {

        this.context = context;
        this.modelArrayList = modelArrayList;
    }

    @Override
    public int getViewTypeCount() {
        return getCount();
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    @Override
    public int getCount() {
        return modelArrayList.size();
    }

    @Override
    public Object getItem(int position) {
        return modelArrayList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final ViewHolder holder;

        if (convertView == null) {
            holder = new ViewHolder(); LayoutInflater inflater = (LayoutInflater) context
                     .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.lv_item, null, true);

            holder.checkBox = (CheckBox) convertView.findViewById(R.id.cb);
            holder.tvAnimal = (TextView) convertView.findViewById(R.id.animal);

            convertView.setTag(holder);
        }
        else {
            // The getTag returns the viewHolder object set as a tag to the view
            holder = (ViewHolder)convertView.getTag();
        }

        holder.checkBox.setText("Checkbox " + position);
        holder.tvAnimal.setText(modelArrayList.get(position).getAnimal());

        holder.checkBox.setChecked(modelArrayList.get(position).getSelected());

        holder.checkBox.setTag(R.integer.btnplusview, convertView);
        holder.checkBox.setTag( position);
        holder.checkBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                View tempview = (View) holder.checkBox.getTag(R.integer.btnplusview);
                TextView tv = (TextView) tempview.findViewById(R.id.animal);
                Integer pos = (Integer)  holder.checkBox.getTag();
                Toast.makeText(context, "Checkbox " + pos + " clicked!", Toast.LENGTH_SHORT).show();

                if (modelArrayList.get(pos).getSelected()){
                    modelArrayList.get(pos).setSelected(false);
                }
                else {
                    modelArrayList.get(pos).setSelected(true);
                }

            }
        });

        return convertView;
    }

    private class ViewHolder {

        protected CheckBox checkBox;
        private TextView tvAnimal;
    }
}

Model is

public class Model {

    private boolean isSelected;

    private String animal;

    public String getAnimal() {
        return animal;
    }

    public void setAnimal(String animal) {
        this.animal = animal;
    }

    public boolean getSelected() {
        return isSelected;
    }

    public void setSelected(boolean selected) {
        isSelected = selected;
    }
}

回答3:

In your getView() you have the following line

holder.cbox.setChecked(false);

which sets CheckBox unchecked every time getView() is called (when you scroll your list, for example)

回答4:

Blockquote

**In Side getView() Method just call like this>>

check.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton arg0, boolean arg1) 
            {

                if(check.isChecked())
                {
                    //checked
                    chkArray[position]=true;
                }
                else
                {   //uncheck
                  chkArray[position]=false;

                }
            }
        });

//check condition for checkboxes
        if(chkArray.length>0)
        {
            for (int i = 0; i < chkArray.length; i++) 
            {
                if(chkArray[position]!=null && chkArray[position])
                {
                    check.setChecked(true);
                }
            }
        }

回答5:

Consider:

holder.cbox.setChecked(false);

Remove this line. When you scrolled the list view every time, the getView() method is called.

回答6:

When we scroll items in listview it restores the value from adapter. That is why the checkbox unchecked. But if we update the adapter with latest value, it will remain checked. For that you need to use setOnClickListener().

All you need to do is update your adapter on checkbox click.You can refer to this link to get an idea

回答7:

I also got this problem before. Android does this to save space; only the items you currently see are loaded, and this is what I found out.

If you are on the bottom on your list, the id 1 is on maybe position 5. I searched on the web and found this out before.

But this will help you :D