Question

我有一个自定义列表适配器，在文本视图中有一个问题，四个选项作为单选按钮中的答案。所有单选按钮都绑定在一个无线电组中。问题是我无法跟踪被检查的按钮。在滚动按钮时会随机检查。如何存储为特定

检查的单选按钮

公共类MCQAdapter扩展了ArrayAdapter {

public MCQAdapter(Activity context, ArrayList<MCQ> mcq) {
    super(context, 0, mcq);
}

@NonNull
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View listItemView = convertView;

    if (listItemView == null) {
        listItemView = LayoutInflater.from(getContext()).inflate(R.layout.activity_mcqlist, parent, false);
    }


    final MCQ currentContent = (MCQ) getItem(position);
    TextView content = (TextView) listItemView.findViewById(R.id.Question_Block);
    content.setText(currentContent.getQuestion());

    RadioGroup rg = (RadioGroup) listItemView.findViewById(R.id.Radio_Group);

    final RadioButton rb1 = (RadioButton) listItemView.findViewById(R.id.Option1_Block);
    rb1.setText(currentContent.getOptionA());

    final RadioButton rb2 = (RadioButton) listItemView.findViewById(R.id.Option2_Block);
    rb2.setText(currentContent.getOptionB());

    final RadioButton rb3 = (RadioButton) listItemView.findViewById(R.id.Option3_Block);
    rb3.setText(currentContent.getOptionC());

    final RadioButton rb4 = (RadioButton) listItemView.findViewById(R.id.Option4_Block);
    rb4.setText(currentContent.getOptionD());

    return listItemView;

}

}

public class MCQ {

String question,optionA,optionB,optionC,optionD,answer,userAnswer;

public MCQ(String quest,String a,String b,String c, String d,String ans){

    question = quest;
    optionA = a;
    optionB = b;
    optionC = c;
    optionD = d;
    answer = ans;

}

public String getQuestion(){
    return question;
}

public String getOptionA() {
    return optionA;
}

public String getOptionB() {
    return optionB;
}

public String getOptionC() {
    return optionC;
}

public String getOptionD() {
    return optionD;
}

public String getAnswer() {
    return answer;
}

public String getUserAnswer() {
    return userAnswer;
}

public void setUserAnswer(String userAnswer) {
    this.userAnswer = userAnswer;
}

}

public class PropertiesOfConstructionMaterail extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_properties_of_construction_materail);

    final ArrayList<MCQ> mcq = new ArrayList<MCQ>();

    //Creating Different Instance Of MCQ to genarte various questions for Properties of Consrtuction Material
    mcq.add(new MCQ("The property of material by which it can be beaten or rolled into thin plates, is called ?",
            "Malleability","Ductility","Plasticity","Elasticity","Malleability"));
    mcq.add(new MCQ("The property by which a body returns to its original shape after removal of the force, is called ?",
            "Plasticity","Elasticity","Ductility","Malleability","Elasticity"));
    mcq.add(new MCQ("The property of a material by which it can be drawn into smaller section due to tension, is called ?"
            ,"Plasticity","Ductility","Elasticity","Malleability","Ductility")); 

MCQAdapter adapter = new MCQAdapter(this,mcq);

    ListView listView = (ListView) findViewById(R.id.list);
    listView.setAdapter(adapter);
}

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_mcqlist"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.silen.civilengineeringmcq.MCQList"
android:orientation="vertical">

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/Question_Block"
    android:textSize="18dp"
    android:textStyle="bold"/>

<RadioGroup
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/Radio_Group">

    <RadioButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/Option1_Block"
        android:checked="false"/>

    <RadioButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/Option2_Block"
        android:checked="false"/>

    <RadioButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/Option3_Block"
        android:checked="false"/>

    <RadioButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/Option4_Block"
        android:checked="false"/>

</RadioGroup>

Answer 1

您应该在PoJo类（MCQ）周围创建一个包装器，将其命名为ViewModel，它将适配器中的当前状态存储起来。在你的情况下，状态是单选按钮的状态。

看起来像是：

class ViewModel extends MCQ {
    MCQ mcq;

    int radioButtonSelectedId;

    public ViewModel(MCQ mcq) {
        this.mcq = mcq;
        this.radioButtonSelectedId = R.id.Option1_Block;
    }

    public void setRadioButtonSelectedId(int id) {
        this.id = id;
    }

    public int getRadioButtonSelectedId() {
        return id;
    }

    //delegates to mcq getter/setter methods
}

您的getView方法：

public View getView(int position, View convertView, ViewGroup parent) {
//your logic above
    radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                viewModel.setRadioButtonSelectedId(checkedId);
            }
        });

    //same for other radio buttons
    rb1.setChecked(viewModel.getRadioButtonSelectedId() == R.id.Option1_Block);
//your logic below
}

正如我上面提到的，适配器中的数组列表将包含ViewModel的包装器，而不是MCQ类直接

final ArrayList<ViewModel> mcqList = new ArrayList<>();
MCQ mcq = new MCQ("The property of material by which it can be beaten or rolled into thin plates, is called ?",
        "Malleability","Ductility","Plasticity","Elasticity","Malleability")
mcqList.add(new ViewModel(mcq));

我认为你应该有一个选择

如何在ArrayAdapter中使用带有4个不同单选按钮的Radiogroup

1 个答案: