How to group RadioButton from different LinearLayouts?
I was wondering if is possible to group each single RadioButton in a unique RadioGroup
maintaining the same structure. My structure look like this:
- LinearLayout_main
- LinearLayout_1
- RadioButton1
- LinearLayout_2
- RadioButton2
- LinearLayout_3
- RadioButton3
- LinearLayout_1
As you can see, now each RadioButton is a child of different LinearLayout. I tried using the structure below, but it doesn't work:
- Radiogroup
- LinearLayout_main
- LinearLayout_1
- RadioButton1
- LinearLayout_2
- RadioButton2
- LinearLayout_3
- RadioButton3
- LinearLayout_1
- LinearLayout_main
It seems that the good people at Google/Android assume that when you use RadioButtons, you don't need the flexibility that comes with every other aspect of the Android UI/layout system. To put it simply: they don't want you to nest layouts and radio buttons. Sigh.
So you gotta work around the problem. That means you must implement radio buttons on your own.
This really isn't too hard. In your onCreate(), set your RadioButtons with their own onClick() so that when they are activated, they setChecked(true) and do the opposite for the other buttons. For example:
class FooActivity {
RadioButton m_one, m_two, m_three;
@Override
protected void onCreate(Bundle savedInstanceState) {
...
m_one = (RadioButton) findViewById(R.id.first_radio_button);
m_two = (RadioButton) findViewById(R.id.second_radio_button);
m_three = (RadioButton) findViewById(R.id.third_radio_button);
m_one.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
m_one.setChecked(true);
m_two.setChecked(false);
m_three.setChecked(false);
}
});
m_two.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
m_one.setChecked(false);
m_two.setChecked(true);
m_three.setChecked(false);
}
});
m_three.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
m_one.setChecked(false);
m_two.setChecked(false);
m_three.setChecked(true);
}
});
...
} // onCreate()
}
Yeah, I know--way old-school. But it works. Good luck!
Use this class that I created. It will find all checkable children in your hierarchy.
import java.util.ArrayList;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Checkable;
import android.widget.LinearLayout;
public class MyRadioGroup extends LinearLayout {
private ArrayList<View> mCheckables = new ArrayList<View>();
public MyRadioGroup(Context context) {
super(context);
}
public MyRadioGroup(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public MyRadioGroup(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
public void addView(View child, int index,
android.view.ViewGroup.LayoutParams params) {
super.addView(child, index, params);
parseChild(child);
}
public void parseChild(final View child)
{
if(child instanceof Checkable)
{
mCheckables.add(child);
child.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
for(int i = 0; i < mCheckables.size();i++)
{
Checkable view = (Checkable) mCheckables.get(i);
if(view == v)
{
((Checkable)view).setChecked(true);
}
else
{
((Checkable)view).setChecked(false);
}
}
}
});
}
else if(child instanceof ViewGroup)
{
parseChildren((ViewGroup)child);
}
}
public void parseChildren(final ViewGroup child)
{
for (int i = 0; i < child.getChildCount();i++)
{
parseChild(child.getChildAt(i));
}
}
}
Well, I wrote this simple class.
Just use it like this:
// add any number of RadioButton resource IDs here
GRadioGroup gr = new GRadioGroup(this,
R.id.radioButton1, R.id.radioButton2, R.id.radioButton3);
or
GRadioGroup gr = new GRadioGroup(rb1, rb2, rb3);
// where RadioButton rb1 = (RadioButton) findViewById(R.id.radioButton1);
// etc.
You can call it in onCreate() of Activity for example. No matter which RadioButton you click, the others will become unchecked. Also, no matters, if some of RadioButtons are inside of some RadioGroup, or not.
Here's the class:
package pl.infografnet.GClasses;
import java.util.ArrayList;
import java.util.List;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewParent;
import android.widget.RadioButton;
import android.widget.RadioGroup;
public class GRadioGroup {
List<RadioButton> radios = new ArrayList<RadioButton>();
/**
* Constructor, which allows you to pass number of RadioButton instances,
* making a group.
*
* @param radios
* One RadioButton or more.
*/
public GRadioGroup(RadioButton... radios) {
super();
for (RadioButton rb : radios) {
this.radios.add(rb);
rb.setOnClickListener(onClick);
}
}
/**
* Constructor, which allows you to pass number of RadioButtons
* represented by resource IDs, making a group.
*
* @param activity
* Current View (or Activity) to which those RadioButtons
* belong.
* @param radiosIDs
* One RadioButton or more.
*/
public GRadioGroup(View activity, int... radiosIDs) {
super();
for (int radioButtonID : radiosIDs) {
RadioButton rb = (RadioButton)activity.findViewById(radioButtonID);
if (rb != null) {
this.radios.add(rb);
rb.setOnClickListener(onClick);
}
}
}
/**
* This occurs everytime when one of RadioButtons is clicked,
* and deselects all others in the group.
*/
OnClickListener onClick = new OnClickListener() {
@Override
public void onClick(View v) {
// let's deselect all radios in group
for (RadioButton rb : radios) {
ViewParent p = rb.getParent();
if (p.getClass().equals(RadioGroup.class)) {
// if RadioButton belongs to RadioGroup,
// then deselect all radios in it
RadioGroup rg = (RadioGroup) p;
rg.clearCheck();
} else {
// if RadioButton DOES NOT belong to RadioGroup,
// just deselect it
rb.setChecked(false);
}
}
// now let's select currently clicked RadioButton
if (v.getClass().equals(RadioButton.class)) {
RadioButton rb = (RadioButton) v;
rb.setChecked(true);
}
}
};
}
Here's my solution based on @lostdev solution and implementation of RadioGroup. It's a RadioGroup modified to work with RadioButtons (or other CompoundButtons) that are nested inside child layouts.
import android.content.Context;
import android.os.Build;
import android.support.annotation.IdRes;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CompoundButton;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import java.util.concurrent.atomic.AtomicInteger;
/**
* This class is a replacement for android RadioGroup - it supports
* child layouts which standard RadioGroup doesn't.
*/
public class RecursiveRadioGroup extends LinearLayout {
public interface OnCheckedChangeListener {
void onCheckedChanged(RecursiveRadioGroup group, @IdRes int checkedId);
}
/**
* For generating unique view IDs on API < 17 with {@link #generateViewId()}.
*/
private static final AtomicInteger sNextGeneratedId = new AtomicInteger(1);
private CompoundButton checkedView;
private CompoundButton.OnCheckedChangeListener childOnCheckedChangeListener;
/**
* When this flag is true, onCheckedChangeListener discards events.
*/
private boolean mProtectFromCheckedChange = false;
private OnCheckedChangeListener onCheckedChangeListener;
private PassThroughHierarchyChangeListener mPassThroughListener;
public RecursiveRadioGroup(Context context) {
super(context);
setOrientation(HORIZONTAL);
init();
}
public RecursiveRadioGroup(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public RecursiveRadioGroup(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
childOnCheckedChangeListener = new CheckedStateTracker();
mPassThroughListener = new PassThroughHierarchyChangeListener();
super.setOnHierarchyChangeListener(mPassThroughListener);
}
@Override
public void setOnHierarchyChangeListener(OnHierarchyChangeListener listener) {
mPassThroughListener.mOnHierarchyChangeListener = listener;
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
// checks the appropriate radio button as requested in the XML file
if (checkedView != null) {
mProtectFromCheckedChange = true;
setCheckedStateForView(checkedView, true);
mProtectFromCheckedChange = false;
setCheckedView(checkedView);
}
}
@Override
public void addView(View child, int index, ViewGroup.LayoutParams params) {
parseChild(child);
super.addView(child, index, params);
}
private void parseChild(final View child) {
if (child instanceof CompoundButton) {
final CompoundButton checkable = (CompoundButton) child;
if (checkable.isChecked()) {
mProtectFromCheckedChange = true;
if (checkedView != null) {
setCheckedStateForView(checkedView, false);
}
mProtectFromCheckedChange = false;
setCheckedView(checkable);
}
} else if (child instanceof ViewGroup) {
parseChildren((ViewGroup) child);
}
}
private void parseChildren(final ViewGroup child) {
for (int i = 0; i < child.getChildCount(); i++) {
parseChild(child.getChildAt(i));
}
}
/**
* <p>Sets the selection to the radio button whose identifier is passed in
* parameter. Using -1 as the selection identifier clears the selection;
* such an operation is equivalent to invoking {@link #clearCheck()}.</p>
*
* @param view the radio button to select in this group
* @see #getCheckedItemId()
* @see #clearCheck()
*/
public void check(CompoundButton view) {
if(checkedView != null) {
setCheckedStateForView(checkedView, false);
}
if(view != null) {
setCheckedStateForView(view, true);
}
setCheckedView(view);
}
private void setCheckedView(CompoundButton view) {
checkedView = view;
if(onCheckedChangeListener != null) {
onCheckedChangeListener.onCheckedChanged(this, checkedView.getId());
}
}
private void setCheckedStateForView(View checkedView, boolean checked) {
if (checkedView != null && checkedView instanceof CompoundButton) {
((CompoundButton) checkedView).setChecked(checked);
}
}
/**
* <p>Returns the identifier of the selected radio button in this group.
* Upon empty selection, the returned value is -1.</p>
*
* @return the unique id of the selected radio button in this group
* @attr ref android.R.styleable#RadioGroup_checkedButton
* @see #check(CompoundButton)
* @see #clearCheck()
*/
@IdRes
public int getCheckedItemId() {
return checkedView.getId();
}
public CompoundButton getCheckedItem() {
return checkedView;
}
/**
* <p>Clears the selection. When the selection is cleared, no radio button
* in this group is selected and {@link #getCheckedItemId()} returns
* null.</p>
*
* @see #check(CompoundButton)
* @see #getCheckedItemId()
*/
public void clearCheck() {
check(null);
}
/**
* <p>Register a callback to be invoked when the checked radio button
* changes in this group.</p>
*
* @param listener the callback to call on checked state change
*/
public void setOnCheckedChangeListener(RecursiveRadioGroup.OnCheckedChangeListener listener) {
onCheckedChangeListener = listener;
}
/**
* Generate a value suitable for use in {@link #setId(int)}.
* This value will not collide with ID values generated at build time by aapt for R.id.
*
* @return a generated ID value
*/
public static int generateViewId() {
for (; ; ) {
final int result = sNextGeneratedId.get();
// aapt-generated IDs have the high byte nonzero; clamp to the range under that.
int newValue = result + 1;
if (newValue > 0x00FFFFFF) newValue = 1; // Roll over to 1, not 0.
if (sNextGeneratedId.compareAndSet(result, newValue)) {
return result;
}
}
}
private class CheckedStateTracker implements CompoundButton.OnCheckedChangeListener {
@Override
public void onCheckedChanged(CompoundButton view, boolean b) {
if (mProtectFromCheckedChange) {
return;
}
mProtectFromCheckedChange = true;
if (checkedView != null) {
setCheckedStateForView(checkedView, false);
}
mProtectFromCheckedChange = false;
int id = view.getId();
setCheckedView(view);
}
}
private class PassThroughHierarchyChangeListener implements OnHierarchyChangeListener {
private OnHierarchyChangeListener mOnHierarchyChangeListener;
@Override
public void onChildViewAdded(View parent, View child) {
if (child instanceof CompoundButton) {
int id = child.getId();
if (id == View.NO_ID) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {
child.setId(generateViewId());
} else {
child.setId(View.generateViewId());
}
}
((CompoundButton) child).setOnCheckedChangeListener(childOnCheckedChangeListener);
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewAdded(parent, child);
}
} else if(child instanceof ViewGroup) {
// View hierarchy seems to be constructed from the bottom up,
// so all child views are already added. That's why we
// manually call the listener for all children of ViewGroup.
for(int i = 0; i < ((ViewGroup) child).getChildCount(); i++) {
onChildViewAdded(child, ((ViewGroup) child).getChildAt(i));
}
}
}
@Override
public void onChildViewRemoved(View parent, View child) {
if (child instanceof RadioButton) {
((CompoundButton) child).setOnCheckedChangeListener(null);
}
if (mOnHierarchyChangeListener != null) {
mOnHierarchyChangeListener.onChildViewRemoved(parent, child);
}
}
}
}
You can use it in your layout the same way as you would a regular RadioGroup with the exception that it works with nested RadioButton views as well:
<RecursiveRadioGroup
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:layout_marginBottom="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
<RadioButton
android:id="@+id/rbNotEnoughProfileInfo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Not enough profile information"/>
<RadioButton
android:id="@+id/rbNotAGoodFit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Not a good fit"/>
<RadioButton
android:id="@+id/rbDatesNoLongerAvailable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Dates no longer available"/>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical">
<RadioButton
android:id="@+id/rbOther"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Other"/>
<android.support.v7.widget.AppCompatEditText
android:id="@+id/etReason"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/tvMessageError"
android:textSize="15sp"
android:gravity="top|left"
android:hint="Tell us more"
android:padding="16dp"
android:background="@drawable/edit_text_multiline_background"/>
</LinearLayout>
</RecursiveRadioGroup>
Sigh.. Really blame that Android lacks such a basic functionality.
Adapted from @ScottBiggs answer, here's the possibly shortest way to do it with Kotlin:
var currentSelected = button1
listOf<RadioButton>(
button1, button2, button3, ...
).forEach {
it.setOnClickListener { _ ->
currentSelected.isChecked = false
currentSelected = it
currentSelected.isChecked = true
}
}