如何确定Android中可以勾选的复选框数量？

Question

嗨，我在列表视图中有复选框我有八个选择，我希望用户只能选中四个，然后锁定复选框，除非他取消选中一个。

这是我的主线：

public class Ch2 extends Activity implements OnItemClickListener{
    ListView lv;
    ArrayAdapter<Model> adapter;
    List<Model> list = new ArrayList<Model>();
    int num;

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.activity_ch2);

        lv = (ListView) findViewById(R.id.listView2);
        adapter = new cusCh2(this,getModel());
        lv.setAdapter(adapter);
        lv.setOnItemClickListener(this);
    }

    @Override
    public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) {
        TextView label = (TextView) v.getTag(R.id.label);
        final CheckBox checkbox = (CheckBox) v.getTag(R.id.check);
        checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){

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

                    Toast.makeText(getApplicationContext(),"hi",Toast.LENGTH_LONG);

                     // disable checkbox
                }
            }
        });
        Toast.makeText(v.getContext(), label.getText().toString()+" "+isCheckedOrNot(checkbox), Toast.LENGTH_LONG).show();

    }

    private String isCheckedOrNot(CheckBox checkbox) {
        if(checkbox.isChecked()) {
            num++;
            if (num == 4) {
                checkbox.setEnabled(false);

            }
            return "is checked";

        } else
            return "is not checked";
    }


    private List<Model> getModel() {
        list.add(new Model("a"));
        list.add(new Model("b"));
        list.add(new Model("c"));
        list.add(new Model("d"));
        list.add(new Model("e"));
        list.add(new Model("f"));
        list.add(new Model("m"));
        list.add(new Model("o"));
        return list;
    }

这是我的 ArrayAdapter

public class cusCh2  extends ArrayAdapter<Model> {

    private final List<Model> list;
    private final Activity context;
    boolean checkAll_flag = false;
    boolean checkItem_flag = false;


    public cusCh2(Activity context, List<Model> list) {
        super(context, R.layout.row, list);
        this.context = context;
        this.list = list;
    }

    static class ViewHolder {
        protected TextView text;
        protected CheckBox checkbox;


    }

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



    ViewHolder viewHolder = null;
    if (convertView == null) {
        LayoutInflater inflator = context.getLayoutInflater();
        convertView = inflator.inflate(R.layout.row, null);
        viewHolder = new ViewHolder();
        viewHolder.text = (TextView) convertView.findViewById(R.id.label);
        viewHolder.checkbox = (CheckBox) convertView.findViewById(R.id.check);
        final ViewHolder finalViewHolder = viewHolder;
        final ViewHolder finalViewHolder1 = viewHolder;
        final ViewHolder finalViewHolder2 = viewHolder;
        viewHolder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                int getPosition = (Integer) buttonView.getTag();  // Here we get the position that we have set for the checkbox using setTag.
                list.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state.

            }
        });
        convertView.setTag(viewHolder);
        convertView.setTag(R.id.label, viewHolder.text);
        convertView.setTag(R.id.check, viewHolder.checkbox);
    } else {
        viewHolder = (ViewHolder) convertView.getTag();
    }
    viewHolder.checkbox.setTag(position); // This line is important.

    viewHolder.text.setText(list.get(position).getName());
    viewHolder.checkbox.setChecked(list.get(position).isSelected());

    return convertView;
}
}

这是我的模特

public class Model {

    private String name;
    private boolean selected;

    public Model(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public boolean isSelected() {
        return selected;
    }

    public void setSelected(boolean selected) {
        this.selected = selected;
    }

我当然有 row.xml 文件

如我所说，我想让我的用户最多可以勾选四个框。

我尝试的解决方案：

    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        int getPosition = (Integer) buttonView.getTag();  // Here we get the position that we have set for the checkbox using setTag.
        list.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state.
        if(!isChecked){
            num++;

            if(num>3){
               finalViewHolder.checkbox.setChecked(false);}
            if(!isChecked){
                num--;
                if(num<3){
                    finalViewHolder.checkbox.setChecked(true);}
            }


        }
    }
});

它作为停止检查工作，但是当我滚动列表时，我丢失了我已经检查过的内容。

编辑 2：

      viewHolder.checkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

               int getPosition = (Integer) buttonView.getTag();  // Here we get the position that we have set for the checkbox using setTag.
              list.get(getPosition).setSelected(buttonView.isChecked()); // Set the value of checkbox to maintain its state.

               Toast toast=  Toast.makeText(getContext(), String.valueOf(getPosition), Toast.LENGTH_SHORT);

                if (isChecked) {
                    num++;
                    l.add(String.valueOf(getPosition));
                    if(l.size() > 3){    
                        finalViewHolder.checkbox.setChecked(false);
                    }         
                    toast.setGravity(Gravity.TOP|Gravity.CENTER_HORIZONTAL, 0, 0);
                    toast.show();
                }

                    else if(!isChecked){
                    finalViewHolder.checkbox.setChecked(true);
                    }

            }

        });

同样，当我滚动时，我丢失了我已经检查过的内容

编辑 2：

   viewHolder.checkbox.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                int getPosition = (Integer) v.getTag();  // Here we get the position that we have set for the checkbox using setTag.
                list.get(getPosition).setSelected(finalViewHolder.checkbox.isChecked()); // Set the value of checkbox to maintain its state.
                Toast toast=  Toast.makeText(getContext(), String.valueOf(getPosition), Toast.LENGTH_SHORT);

                if (finalViewHolder.checkbox.isChecked()) {

                    l.add(String.valueOf(getPosition));
                    toast.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL, 0, 0);
                    toast.show();

                    if (l.size() > 4) {
                        finalViewHolder.checkbox.setChecked(false);
                    }


                    if (!finalViewHolder.checkbox.isChecked()) {
                        finalViewHolder.checkbox.setChecked(true);

                    }

                }
            }

        }
    );

希望有人能帮帮我，谢谢

Answer 1

这是因为当您滚动列表时，调用 getView 时 setOnCheckedChangeListener 将是 called.evrytime...而不是在 checkBox

上使用 onClickListener

   checkbox.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {

                    if (checkbox.isChecked()) {

                    } else if (!checkbox.isChecked()) {

                        }
                    }

                }
            });

Answer 2

您可以使用存储选中的列表 items.You 可以将选中的项目放入 OnCheckChangelistner/OnClicklistner 中的列表。如果用户取消选中该项目并且它已经在列表中而不是将其从 list.And 始终检查列表的大小以计算 items.You 可以根据需要选择列表类型，例如：- 列表或任何存储 ID 的内容。

        holder.cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            // TODO Auto-generated method stub
               Log.e("checked : ", "Clicked on Checkbox: " +contactList.get(position).getName() +" is " + isChecked);




              ContactPhone cp = contactList.get(position);
              if(isChecked){
                  cp.setState(isChecked);
                  addToSelected(cp);

              }else{
                  cp.setState(isChecked);
                  removeSelected(cp);
              }

              if(selected_contats.size() > 4){

               }else{

                   }
               }

        }
    });

就是这样...

Answer 3

好的伙计们，谢谢你们的宝贵时间，我找到了我的解决方案

即使你写checkbox.setChecked(false)的问题；即使不使用我的 Arraylist，android 仍然算作已检查，成为增加曾经检查过或未检查过的内容，当成为 setChecked(false) 时，我使用 make list 删除最后一项来停止此操作；现在它工作正常此解决方案代码

     viewHolder.checkbox.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                int getPosition = (Integer) v.getTag();  

                if (finalViewHolder.checkbox.isChecked()) {

                    l.add(getItem(getPosition).getName());
                    Toast toast=  Toast.makeText(getContext(),String.valueOf(l.size()), Toast.LENGTH_SHORT);
                    toast.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL, 0, 0);
                    toast.show();

                    if (l.size() > 4) {
                        finalViewHolder.checkbox.setChecked(false);
                        l.remove(getItem(getPosition).getName());



                    }

                }
                   else if (!finalViewHolder.checkbox.isChecked()) {
                        l.remove(getItem(getPosition).getName());

                    }

                list.get(getPosition).setSelected(finalViewHolder.checkbox.isChecked());
            }

        }
    );

如何确定Android中可以勾选的复选框数量？

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