android – 如何在自定义ListView适配器中处理RadioGroup的onCheckedChangeListener
作者：互联网
我正在开发一个具有自定义布局的列表视图的应用程序,如下所示：
它在RadioGroup中有4个RadioButtons和一个TextView.实际上,它将显示为问题(TextView)和答案(RadioButtons)列表.上面的视图在我的自定义适配器中膨胀,该适配器扩展了ArrayAdapter< Question>.
问题是,我应该如何在自定义适配器中维护RadioButton的状态？按下/选中RadioButton并向下滚动列表时,适配器会自动回收视图,并且RadioButton状态将丢失.
>那么,任何人都可以指导任何关于此的链接/信息吗？
>或者我应该如何实施问题答案清单？
第一条遵循：
http://www.vogella.de/articles/AndroidListView/article.html
上面的链接使用CheckBox,类似的方式我想使用RadioGroup(RadioButtons)而不是CheckBoxes.
解决方法:
它很容易适应该教程,因此您可以使用RadioGroup而不是CheckBox.贝娄就是一个例子(我使用了一个带有4个RadioButton的RadioGroup).首先,您必须修改Model类,以便它可以保存新数据：
public class Model {
String question; // hold the question
int current = NONE; // hold the answer picked by the user, initial is NONE(see below)
public static final int NONE = 1000; // No answer selected
public static final int ANSWER_ONE_SELECTED = 0; // first answer selected
public static final int ANSWER_TWO_SELECTED = 1; // second answer selected
public static final int ANSWER_THREE_SELECTED = 2; // third answer selected
public static final int ANSWER_FOUR_SELECTED = 3; // forth answer selected
public Model(String question) {
this.question = question;
}
}
然后修改getView()方法以根据模型设置视图：
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
ViewHolder holder = null;
if (v == null) {
v = inflater.inflate(R.layout.the_row, parent, false);
holder = new ViewHolder(v);
v.setTag(holder);
holder.group
.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
public void onCheckedChanged(RadioGroup group,
int checkedId) {
Integer pos = (Integer) group.getTag(); // To identify the Model object i get from the RadioGroup with getTag()
// an integer representing the actual position
Model element = list.get(pos);
switch (checkedId) { //set the Model to hold the answer the user picked
case R.id.answer0:
element.current = Model.ANSWER_ONE_SELECTED;
break;
case R.id.answer1:
element.current = Model.ANSWER_TWO_SELECTED;
break;
case R.id.answer2:
element.current = Model.ANSWER_THREE_SELECTED;
break;
case R.id.answer3:
element.current = Model.ANSWER_FOUR_SELECTED;
break;
default:
element.current = Model.NONE; // Something was wrong set to the default
}
}
});
} else {
holder = (ViewHolder) v.getTag();
}
holder.group.setTag(new Integer(position)); // I passed the current position as a tag
holder.t.setText(list.get(position).question); // Set the question body
if (list.get(position).current != Model.NONE) {
RadioButton r = (RadioButton) holder.group.getChildAt(list
.get(position).current);
r.setChecked(true);
} else {
holder.group.clearCheck(); // This is required because although the Model could have the current
// position to NONE you could be dealing with a previous row where
// the user already picked an answer.
}
return v;
}
然后是ViewHolder类：
class ViewHolder {
TextView t = null;
RadioGroup group;
ViewHolder(View v) {
t = (TextView) v.findViewById(R.id.textView1);
group = (RadioGroup) v.findViewById(R.id.group_me);
}
}
带有RadioGroup的xml布局：
<?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="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<RadioGroup
android:id="@+id/group_me"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<RadioButton
android:id="@+id/answer0"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="false"
android:text="Ans0" />
<RadioButton
android:id="@+id/answer1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="false"
android:text="Ans1" />
<RadioButton
android:id="@+id/answer2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="false"
android:text="Ans2" />
<RadioButton
android:id="@+id/answer3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="false"
android:text="Ans3" />
</RadioGroup>
</LinearLayout>
标签：android,android-listview,radio-button,android-arrayadapter,custom-adapter 来源： https://codeday.me/bug/20190713/1447337.html