如何在 Android 中计算 ListView 上的选中项

Question

亲爱的 Stackers，你好，

我遇到了一个小问题，希望您能帮我解决这个问题。让我们切入正题。

我的代码应该做什么？ -> 我的代码应该设置一个带有 CheckBoxes 的 ListView，然后我应该能够选中框，然后计算按下按钮后选中了多少个框。然后我应该将对象传递给下一个 Activity，但这不应该是这个问题的一部分，我只是为了上下文添加这个，它可能对解决方案很重要。

我的代码没有做什么？ -> 我的代码不计算盒子。 listView.getCheckedItemIds().length)); 仅行 returns 0.

在重新阅读 ListView、List、Adapter、View 等文档并尝试了一些不同的方法（和教程，一些来自 Whosebug 的方法）之后，我不确定如何处理这个或从哪里开始

这是代码 ------------------> 主要 Class <----------------

     package com.example.christian.listviewwithcheckbox_model;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
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;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends Activity implements AdapterView.OnItemClickListener {

    int checkCounter = 0;

    ListView listView;
    ArrayAdapter<Model> adapter;
    List<Model> list = new ArrayList<Model>();
    private Button mButton;
    private TextView mCounter;

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

        listView = (ListView) findViewById(R.id.my_list);
        adapter = new MyAdapter(this, getModel());
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(this);


        mCounter = (TextView) findViewById(R.id.counter_text);

        mButton = (Button) findViewById(R.id.count_button);
        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int count = 0;
                int size = list.size();
                for (int i=0; i<size; i++){
                    if (list.get(i).isSelected()){
                        count++;
                    }
                }
                mCounter.setText(String.format("%d", count));
            }
        });
    }



    @Override
    public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) {
        TextView label = (TextView) v.getTag(R.id.label);
        CheckBox checkbox = (CheckBox) v.getTag(R.id.check);
        Toast.makeText(v.getContext(), label.getText().toString() + " " + isCheckedOrNot(checkbox), Toast.LENGTH_LONG).show();
    }

    private String isCheckedOrNot(CheckBox checkbox) {
        if (checkbox.isChecked()) {
            return "is checked";
        } else {
             return "is not checked";
        }
    }

    private List<Model> getModel() {
        list.add(new Model("Linux"));
        list.add(new Model("Windows7"));
        list.add(new Model("Suse"));
        list.add(new Model("Eclipse"));
        list.add(new Model("Ubuntu"));
        list.add(new Model("Solaris"));
        list.add(new Model("Android"));
        list.add(new Model("iPhone"));
        list.add(new Model("Java"));
        list.add(new Model(".Net"));
        list.add(new Model("PHP"));
        list.add(new Model("Linux"));
        list.add(new Model("Windows7"));
        list.add(new Model("Suse"));
        list.add(new Model("Eclipse"));
        list.add(new Model("Ubuntu"));
        list.add(new Model("Solaris"));
        list.add(new Model("Android"));
        list.add(new Model("iPhone"));
        list.add(new Model("Java"));
        list.add(new Model(".Net"));
        list.add(new Model("PHP"));
        list.add(new Model("Linux"));
        list.add(new Model("Windows7"));
        list.add(new Model("Suse"));
        list.add(new Model("Eclipse"));
        list.add(new Model("Ubuntu"));
        list.add(new Model("Solaris"));
        list.add(new Model("Android"));
        list.add(new Model("iPhone"));
        list.add(new Model("Java"));
        list.add(new Model(".Net"));
        list.add(new Model("PHP"));
        return list;
    }
}

----------------> 适配器 class <-------------------- --

    package com.example.christian.listviewwithcheckbox_model;

import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;

import java.util.List;

public class MyAdapter extends ArrayAdapter<Model> {

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

    public MyAdapter(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(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);
            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;
} }

--------------------> 型号 class <---------------- -----

    package com.example.christian.listviewwithcheckbox_model;

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;
    }
}

好吧，那是我的问题，很抱歉在上一个帖子之后这么快就打开了一个帖子，但此时我遇到了一些麻烦，需要一个解决方案。提前谢谢你，祝你有美好的一天。伊欧墨

编辑：问题已由 Hoang Nguyen 和 Hardy 解决，非常感谢上面的代码已经更新并显示了现在的工作代码。

Answer 1

您使用自定义复选框，因此无法使用方法getCheckedItemIds()，请参考doc and ListView Mode

对于您的问题，可以像这样轻松更改按钮点击方法：

    mButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            int count = 0;
            int size = list.size();
            for (int i=0; i<size; i++){
                if (list.get(i).isSelected()){
                    count++;
                }
            }
            mCounter.setText(String.format("%d", count));
        }
    });

Answer 2

把你的下面几行

  convertView.setTag(viewHolder);
        convertView.setTag(R.id.label, viewHolder.text);
        convertView.setTag(R.id.check, viewHolder.checkbox);

以上

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.
            }
        });

因此您的代码最终将如下所示：-

 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);

        convertView.setTag(viewHolder);
        convertView.setTag(R.id.label, viewHolder.text);
        convertView.setTag(R.id.check, viewHolder.checkbox);
    } else {
        viewHolder = (ViewHolder) convertView.getTag();
    }
       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.
            }
        });

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