Android getting value from selected radiobutton

问题:

I have a piece of code with three RadioButtons within a RadioGroup. I want to set an onCheckedListener that will show the value of the RadioButton in a Toast. However what I have gotten so far is not working. How do I get the value of the RadioButton and display it in a Toast? Thank you in advance, this is my code:

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.Toast;

public class MainActivity extends Activity {

    RadioGroup rg;

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

        RadioGroup rg = (RadioGroup) findViewById(R.id.radioGroup1);
        final String value =
            ((RadioButton)findViewById(rg.getCheckedRadioButtonId()))
            .getText().toString();

        rg.setOnCheckedChangeListener(new OnCheckedChangeListener() {
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                Toast.makeText(getBaseContext(), value, Toast.LENGTH_SHORT).show();
            }
        });
    }
}

XML file:

<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <RadioGroup
        android:id="@+id/radioGroup1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="152dp" >

        <RadioButton
            android:id="@+id/radio0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Choose 1" />

         <RadioButton
            android:id="@+id/radio1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Choose 2" />

         <RadioButton
            android:id="@+id/radio2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Choose 3" />
     </RadioGroup>
 </RelativeLayout>

回答1:

Tested and working. Check this

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MyAndroidAppActivity extends Activity {

  private RadioGroup radioGroup;
  private RadioButton radioButton;
  private Button btnDisplay;

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    addListenerOnButton();

  }

  public void addListenerOnButton() {

    radioGroup = (RadioGroup) findViewById(R.id.radio);
    btnDisplay = (Button) findViewById(R.id.btnDisplay);

    btnDisplay.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

                // get selected radio button from radioGroup
            int selectedId = radioGroup.getCheckedRadioButtonId();

            // find the radiobutton by returned id
            radioButton = (RadioButton) findViewById(selectedId);

            Toast.makeText(MyAndroidAppActivity.this,
                radioButton.getText(), Toast.LENGTH_SHORT).show();

        }

    });

  }
}

xml

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

        <RadioButton
            android:id="@+id/radioMale"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radio_male" 
            android:checked="true" />

        <RadioButton
            android:id="@+id/radioFemale"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radio_female" />

    </RadioGroup>

回答2:

In case, if you want to do some job on the selection of one of the radio buttons (without having any additional OK button or something), your code is fine, updated little.

public class MainActivity extends Activity {

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

        RadioGroup rg = (RadioGroup) findViewById(R.id.radioGroup1);

        rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() 
        {
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                switch(checkedId){
                    case R.id.radio0:
                        // do operations specific to this selection
                        break;
                    case R.id.radio1:
                        // do operations specific to this selection
                        break;
                    case R.id.radio2:
                        // do operations specific to this selection
                        break;
                }   
            }
        });
    }
}

回答3:

radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
       @Override
       public void onCheckedChanged(RadioGroup group, int checkedId)
       {
           radioButton = (RadioButton) findViewById(checkedId);
           Toast.makeText(getBaseContext(), radioButton.getText(), Toast.LENGTH_SHORT).show();
       }
   }
   );

回答4:

For anyone who is populating programmatically and looking to get an index, you might notice that the checkedId changes as you return to the activity/fragment and you re-add those radio buttons. One way to get around that is to set a tag with the index:

    for(int i = 0; i < myNames.length; i++) {
        rB = new RadioButton(getContext());
        rB.setText(myNames[i]);
        rB.setTag(i);
        myRadioGroup.addView(rB,i);
    }

Then in your listener:

    myRadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            RadioButton radioButton = (RadioButton) group.findViewById(checkedId);
            int mySelectedIndex = (int) radioButton.getTag();
        }
    });

回答5:

just use getCheckedRadioButtonId() function to determine wether if anything is checked, if -1 is return, you can avoid toast appear

回答6:

mRadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
    @Override
    public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {
        RadioButton radioButton = (RadioButton)group.findViewById(checkedId);
    }
});

回答7:

int genid=gender.getCheckedRadioButtonId();
RadioButton radioButton = (RadioButton) findViewById(genid);
String gender=radioButton.getText().toString();

Hope this works. You can convert your output to string in the above manner. gender.getCheckedRadioButtonId(); - gender is the id of RadioGroup.

回答8:

Radiogroup rgteam;
String team;
rgteam.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {
            RadioButton rb= (RadioButton) findViewById(checkedId);
            team = rb.getText().toString();
        }
    });

回答9:

Thanks a lot to Chris.

This is my solution:

RadioGroup radgroup_opcionesEventos = null;


 private static String[] arrayEventos = {
            "Congestión", "Derrumbe", "Accidente"
    };
@Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        radgroup_opcionesEventos = (RadioGroup)findViewById(R.id.rg_opciones_evento);
        int i=0;//a.new.ln
        for(String evento : arrayEventos) {
            //RadioButton nuevoRadio = crearRadioButton(evento);//a.old.ln
            RadioButton nuevoRadio = crearRadioButton(evento,i);//a.new.ln
            radgroup_opcionesEventos.addView(nuevoRadio,i);
        }

        RadioButton primerRadio = (RadioButton) radgroup_opcionesEventos.getChildAt(0);
        primerRadio.setChecked(true);
}

private RadioButton crearRadioButton(String evento, int n)
    {
        //RadioButton nuevoRadio = new RadioButton(this);//a.old.ln
        RadioButton nuevoRadio = new RadioButton(getApplicationContext());//a.new.ln

        LinearLayout.LayoutParams params = new RadioGroup.LayoutParams(
                RadioGroup.LayoutParams.WRAP_CONTENT,
                RadioGroup.LayoutParams.WRAP_CONTENT);
        nuevoRadio.setLayoutParams(params);
        nuevoRadio.setText(evento);
        nuevoRadio.setTag(evento);
        return nuevoRadio;
    }


@Override
    protected void onResume()
    {
        radgroup_opcionesEventos.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                RadioButton radioButton = (RadioButton) group.findViewById(checkedId);
                //int mySelectedIndex = (int) radioButton.getTag();
                String mySelectedIndex = radioButton.getTag().toString();
            }
        });
        super.onResume();
    }

回答10:

RadioGroup in XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent">
<RadioGroup
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">
    <RadioButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Java"/>

    </RadioGroup>
</RelativeLayout>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="150dp"
        android:layout_marginLeft="100dp"
        android:textSize="18dp"
        android:text="Select Your Course"
        android:textStyle="bold"
        android:id="@+id/txtView"/>
<RadioGroup
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:id="@+id/rdGroup"
    android:layout_below="@+id/txtView">
    <RadioButton
        android:id="@+id/rdbJava"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:layout_marginLeft="100dp"
        android:text="Java"
        android:onClick="onRadioButtonClicked"/>
    <RadioButton
        android:id="@+id/rdbPython"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:layout_marginLeft="100dp"
        android:text="Python"
        android:onClick="onRadioButtonClicked"/>
    <RadioButton
        android:id="@+id/rdbAndroid"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:layout_marginLeft="100dp"
        android:text="Android"
        android:onClick="onRadioButtonClicked"/>
    <RadioButton
        android:id="@+id/rdbAngular"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:layout_marginLeft="100dp"
        android:text="AngularJS"
        android:onClick="onRadioButtonClicked"/>
</RadioGroup>
    <Button
        android:id="@+id/getBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="100dp"
        android:layout_below="@+id/rdGroup"
        android:text="Get Course" />
</RelativeLayout>

MainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    RadioButton android, java, angular, python;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        android = (RadioButton)findViewById(R.id.rdbAndroid);
        angular = (RadioButton)findViewById(R.id.rdbAngular);
        java = (RadioButton)findViewById(R.id.rdbJava);
        python = (RadioButton)findViewById(R.id.rdbPython);
        Button btn = (Button)findViewById(R.id.getBtn);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String result = "Selected Course: ";
                result+= (android.isChecked())?"Android":(angular.isChecked())?"AngularJS":(java.isChecked())?"Java":(python.isChecked())?"Python":"";
                Toast.makeText(getApplicationContext(), result, Toast.LENGTH_SHORT).show();
            }
        });
    }
    public void onRadioButtonClicked(View view) {
        boolean checked = ((RadioButton) view).isChecked();
        String str="";
        // Check which radio button was clicked
        switch(view.getId()) {
            case R.id.rdbAndroid:
                if(checked)
                str = "Android Selected";
                break;
            case R.id.rdbAngular:
                if(checked)
                str = "AngularJS Selected";
                break;
            case R.id.rdbJava:
                if(checked)
                str = "Java Selected";
                break;
            case R.id.rdbPython:
                if(checked)
                str = "Python Selected";
                break;
        }
        Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT).show();
    }
}

回答11:

I have had problems getting radio buttons id's as well when the RadioButtons are dynamically generated. It does not seem to work if you try to manually set the ID's using RadioButton.setId(). What worked for me was to use View.getChildAt() and View.getParent() in order to iterate through the radio buttons and determine which one was checked. All you need is to first get the RadioGroup via findViewById(R.id.myRadioGroup) and then iterate through it's children. You'll know as you iterate through which button you are on, and you can simply use RadioButton.isChecked() to determine if that is the button that was checked.