如何在android中的ListView arrayadapter上选择/取消选择单选按钮

Question

我在列表视图适配器中使用单选按钮，我想要的是选择/取消选择我单击的单选按钮。

Answer 1

将您的单选按钮状态保存在列表中，或者如果在这种情况下只有一个选择，您可以将特定位置保存在 int 变量中，然后在选择时更新变量的值，然后执行adapter.notifyDataSetChanged()。您需要在getView 中编写代码以反映更改。

粗略的例子：（我现在对listview（检查recyclerview）很老了，但是你的adpater应该是这样的）

Adapter{
 int selectedPosition = -1;  // initially nothing selected  

 getView(..,..., int position){

   if(selectedPosition==position){
   holder.radioButton.setChecked(true);
   }else{
   holder.radioButton.setChecked(false);
   }

   holder.radioButton.setTag(position);

   holder.radioButton.onClick(){
   selectedPosition = (Integer)holder.radioButton.getTag();
   notifyDataSetChanged();
   }  

 )


static class Holder {
    RadioButton radioButton;
}

Answer 2

给radionButton添加一个clickListener，这样如果你点击radionButton，如果它被选中，它将取消选择。 （默认情况下，如果不勾选，点击会勾选）

radioButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                if (radioButton.isChecked()) {
                radioButton.setChecked(false);
                }
            }
        });

Answer 3

在这一步首先我们得到Button和ListView的引用。之后我们为问题创建一个字符串数组，然后设置一个adapter 来填充ListView 中的数据。最后，我们在Button 上执行setOnClickListener 事件，因此每当用户点击Button 时，选择的问题答案都会使用Toast 显示。

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

ListView simpleList;
String[] questions;
Button submit;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// get the string array from string.xml file
questions = getResources().getStringArray(R.array.questions);
// get the reference of ListView and Button
simpleList = (ListView) findViewById(R.id.simpleListView);
submit = (Button) findViewById(R.id.submit);
// set the adapter to fill the data in the ListView
CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), questions);
simpleList.setAdapter(customAdapter);
// perform setOnClickListerner event on Button
submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String message = "";
// get the value of selected answers from custom adapter
for (int i = 0; i < CustomAdapter.selectedAnswers.size(); i++) {
message = message + "\n" + (i + 1) + " " + CustomAdapter.selectedAnswers.get(i);
}
// display the message on screen with the help of Toast.
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show();
}
});
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}
}


In this step we create a custom adapter class and extends BaseAdapter in this class. In this step we firstly set the data in the list and then perform setOnCheckedChangeListener event on RadioButton.


import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CompoundButton;
import android.widget.RadioButton;
import android.widget.TextView;

import java.util.ArrayList;


public class CustomAdapter extends BaseAdapter {
Context context;
String[] questionsList;
LayoutInflater inflter;
public static ArrayList<String> selectedAnswers;

public CustomAdapter(Context applicationContext, String[] questionsList) {
this.context = context;
this.questionsList = questionsList;
// initialize arraylist and add static string for all the questions
selectedAnswers = new ArrayList<>();
for (int i = 0; i < questionsList.length; i++) {
selectedAnswers.add("Not Attempted");
}
inflter = (LayoutInflater.from(applicationContext));
}

@Override
public int getCount() {
return questionsList.length;
}

@Override
public Object getItem(int i) {
return null;
}

@Override
public long getItemId(int i) {
return 0;
}

@Override
public View getView(final int i, View view, ViewGroup viewGroup) {
view = inflter.inflate(R.layout.list_items, null);
// get the reference of TextView and Button's
TextView question = (TextView) view.findViewById(R.id.question);
RadioButton yes = (RadioButton) view.findViewById(R.id.yes);
RadioButton no = (RadioButton) view.findViewById(R.id.no);
// perform setOnCheckedChangeListener event on yes button
yes.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
// set Yes values in ArrayList if RadioButton is checked
if (isChecked)
selectedAnswers.set(i, "Yes");
}
});
// perform setOnCheckedChangeListener event on no button
no.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
// set No values in ArrayList if RadioButton is checked
if (isChecked)
selectedAnswers.set(i, "No");

}
});
// set the value in TextView
question.setText(questionsList[i]);
return view;
}
}

Answer 4

radiogroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                // Radio button
                RadioButton rb1=(RadioButton)findViewById(R.id.rdb1);
                if (rb1.isChecked()){
                    Toast.makeText(MainActivity.this, "1 option selected", Toast.LENGTH_LONG).show();
                }
                else{
                    Toast.makeText(MainActivity.this, "2 option selected", Toast.LENGTH_LONG).show();

                }
            }
        });