当我们滚动列表时，自定义 ListView 中的 Android 单选按钮会更改其状态

Question

我是初学者，遇到一个问题，我正在创建一个包含两个 RadioButton 和一个 TextView 的 ListView。一切顺利，但是当我设置 RadioButton 并滚动它时，先前 RadioButton 的值会改变它们的值或显着失去它们的状态。我一直在努力解决这个问题。我应该做哪些改变来克服这个问题？

主 Activity .java

public class MainActivity extends Activity {

     private ListView listView1;
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            Option weather_data[] = new Option[]
                    {
                        new Option("Heading1"),
                        new Option("Heading12"),
                        new Option("Heading3"),
                        new Option("Heading4"),
                        new Option("Heading5"),
                        new Option("Heading6"),
                        new Option("Heading7"),
                        new Option("Heading8"),
                        new Option("Heading9"),
                        new Option("Heading10")
                    };
            RadioGroupAdapter adapter = new RadioGroupAdapter(this, 
                            R.layout.listitem, weather_data);
                    listView1 = (ListView)findViewById(R.id.list);
                    listView1.setAdapter(adapter);
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            getMenuInflater().inflate(R.menu.activity_main, menu);
            return true;
        }
    }

选项.java

public class Option {
     public String title;
        public Option(){
            super();
        }

        public Option( String title) {
            super();
            this.title = title;
        }
    }

RadioGroupAdapter.java

public class RadioGroupAdapter extends ArrayAdapter<Option> {

    Context context;
    int layoutResourceId;
    Option data[] = null;

    public RadioGroupAdapter(Context context, int layoutResourceId,
            Option[] data) {
        super(context, layoutResourceId, data);
        this.layoutResourceId = layoutResourceId;
        this.context = context;
        this.data = data;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row = convertView;
        MatrixHolder holder = null;

        if (row == null) {
            LayoutInflater inflater = ((Activity) context).getLayoutInflater();
            row = inflater.inflate(layoutResourceId, parent, false);

            holder = new MatrixHolder();
            holder.txtTitle = (TextView) row.findViewById(R.id.heading);
            holder.group = (RadioGroup) row.findViewById(R.id.radio_group1);
            final RadioButton[] rb = new RadioButton[2];
            for(int i=0; i<2; i++){
                rb[i]  = new RadioButton(context);
                //rb[i].setButtonDrawable(R.drawable.single_radio_chice);
                rb[i].setId(i);
                RadioGroup.LayoutParams params = new RadioGroup.LayoutParams(
                        0, LayoutParams.WRAP_CONTENT);
                params.weight=1.0f;
                params.setMargins(5, 0, 5, 10);
                holder.group.addView(rb[i],params); //the RadioButtons are added to the radioGroup instead of the layout
            }
            row.setTag(holder);
        } else {
            holder = (MatrixHolder) row.getTag();
        }

        Option option = data[position];
        holder.txtTitle.setText(option.title);
        return row;
    }

    static class MatrixHolder {
        TextView txtTitle;
        RadioGroup group;
        int position;
    }
}

列表项.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:weightSum="100" >

    <TextView
        android:id="@+id/heading"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="left"
        android:padding="10dp"
        android:textSize="18sp"
        android:textStyle="bold"
        android:layout_weight="50" />

    <RadioGroup
        android:id="@+id/radio_group1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical|center_horizontal"
        android:orientation="horizontal"
        android:layout_weight="50" >
    </RadioGroup>

</LinearLayout>

Answer 1

您需要为每个项目保存 RadioButton 的状态，因此在滚动时在 getView() 方法中，它首先会检查每个 RadioButton 的状态。

第 1 步:- 您需要创建一个 Pojo 类(Setter 和 Getter)来保存 RadioButton 的状态。

有关更多详细信息，请访问以下链接

http://amitandroid.blogspot.in/2013/03/android-listview-with-checkbox-and.html

这个例子是一个带有 CheckBox 的 ListView，你需要根据你的要求把它改成 RadioButton。