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This article will explain in detail how to achieve RadioGroup multi-line display in Android. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

Example:

Import android.content.Context;import android.content.res.TypedArray;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.view.accessibility.AccessibilityEvent;import android.view.accessibility.AccessibilityNodeInfo;import android.widget.CompoundButton;import android.widget.LinearLayout;import android.widget.RadioButton;public class RadioGroup extends LinearLayout {/ / holds the checked id; the selection is empty by default private int mCheckedId =-1; / / tracks children radio buttons checked state private CompoundButton.OnCheckedChangeListener mChildOnCheckedChangeListener / / when true, mOnCheckedChangeListener discards events private boolean mProtectFromCheckedChange = false; private OnCheckedChangeListener mOnCheckedChangeListener; private PassThroughHierarchyChangeListener mPassThroughListener; / * {@ inheritDoc} * / public RadioGroup (Context context) {super (context); setOrientation (VERTICAL); init ();} / * * {@ inheritDoc} * / public RadioGroup (Context context, AttributeSet attrs) {super (context, attrs); mCheckedId = View.NO_ID; final int index = VERTICAL; setOrientation (index); init () } private void init () {mChildOnCheckedChangeListener = new CheckedStateTracker (); mPassThroughListener = new PassThroughHierarchyChangeListener (); super.setOnHierarchyChangeListener (mPassThroughListener);} / * * {@ inheritDoc} * / @ Override public void setOnHierarchyChangeListener (OnHierarchyChangeListener listener) {/ / the user listener is delegated to our pass-through listener mPassThroughListener.mOnHierarchyChangeListener = listener;} / * * {@ inheritDoc} * / @ Override protected void onFinishInflate () {super.onFinishInflate () / / checks the appropriate radio button as requested in the XML file if (mCheckedId! =-1) {mProtectFromCheckedChange = true; setCheckedStateForView (mCheckedId, true); mProtectFromCheckedChange = false; setCheckedId (mCheckedId);} @ Override public void addView (final View child, int index, ViewGroup.LayoutParams params) {if (child instanceof RadioButton) {child.setOnTouchListener (new OnTouchListener () {@ Override public boolean onTouch (View v, MotionEvent event) {(RadioButton) child) .setChecked (true) CheckRadioButton ((RadioButton) child); if (mOnCheckedChangeListener! = null) {mOnCheckedChangeListener.onCheckedChanged (RadioGroup.this, child.getId ());} return true;}});} else if (child instanceof LinearLayout) {int childCount = ((LinearLayout) child). GetChildCount (); for (int I = 0; I < childCount; iTunes +) {View view = (LinearLayout) child) .getChildAt (I) If (view instanceof RadioButton) {final RadioButton button = (RadioButton) view; button.setOnTouchListener (new OnTouchListener () {@ Override public boolean onTouch (View v, MotionEvent event) {button.setChecked (true); checkRadioButton (button); if (mOnCheckedChangeListener! = null) {mOnCheckedChangeListener.onCheckedChanged (RadioGroup.this, button.getId ());} return true;}}) } super.addView (child, index, params);} private void checkRadioButton (RadioButton radioButton) {View child; int radioCount = getChildCount (); for (int I = 0; I < radioCount; iTunes +) {child = getChildAt (I); if (child instanceof RadioButton) {if (child = = radioButton) {/ / do nothing} else {(RadioButton) child) .setChecked (false) } else if (child instanceof LinearLayout) {int childCount = ((LinearLayout) child). GetChildCount (); for (int j = 0; j < childCount; jungle +) {View view = ((LinearLayout) child) .getChildAt (j); if (view instanceof RadioButton) {final RadioButton button = (RadioButton) view; if (button = = radioButton) {/ / do nothing} else {button.setChecked (false) } / *

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 ()}.

* * @ param id the unique id of the radio button to select in this group * @ see # getCheckedRadioButtonId () @ see # clearCheck () * / public void check (int id) {/ / don't even bother if (id! =-1 & & (id = = mCheckedId)) {return;} if (mCheckedId! =-1) {setCheckedStateForView (mCheckedId, false);} if (id! =-1) {setCheckedStateForView (id, true);} setCheckedId (id) } private void setCheckedId (int id) {mCheckedId = id;} private void setCheckedStateForView (int viewId, boolean checked) {View checkedView = findViewById (viewId); if (checkedView! = null & & checkedView instanceof RadioButton) {((RadioButton) checkedView) .setChecked (checked);}} / * *

Returns the identifier of the selected radio button in this group. * Upon empty selection, the returned value is-1.

* * @ return the unique id of the selected radio button in this group * @ attr ref android.R.styleable#RadioGroup_checkedButton * @ see # check (int) * @ see # clearCheck () * / public int getCheckedRadioButtonId () {return mCheckedId;} / * *

Clears the selection. When the selection is cleared, no radio button * in this group is selected and {@ link # getCheckedRadioButtonId ()} returns * null.

* * @ see # check (int) * @ see # getCheckedRadioButtonId () * / public void clearCheck () {check (- 1);} / * *

Register a callback to be invoked when the checked radio button * changes in this group.

* * @ param listener the callback to call on checked state change * / public void setOnCheckedChangeListener (OnCheckedChangeListener listener) {mOnCheckedChangeListener = listener;} / * * {@ inheritDoc} * / @ Override public LayoutParams generateLayoutParams (AttributeSet attrs) {return new RadioGroup.LayoutParams (getContext (), attrs);} / * * {@ inheritDoc} * / @ Override protected boolean checkLayoutParams (ViewGroup.LayoutParams p) {return p instanceof RadioGroup.LayoutParams } @ Override protected LinearLayout.LayoutParams generateDefaultLayoutParams () {return new LayoutParams (LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);} @ Override public void onInitializeAccessibilityEvent (AccessibilityEvent event) {super.onInitializeAccessibilityEvent (event); event.setClassName (RadioGroup.class.getName ());} @ Override public void onInitializeAccessibilityNodeInfo (AccessibilityNodeInfo info) {super.onInitializeAccessibilityNodeInfo (info); info.setClassName (RadioGroup.class.getName ()) } public static class LayoutParams extends LinearLayout.LayoutParams {/ * * {@ inheritDoc} * / public LayoutParams (Context c, AttributeSet attrs) {super (c, attrs);} / * * {@ inheritDoc} * / public LayoutParams (int w, int h) {super (w, h);} / * * {@ inheritDoc} * / public LayoutParams (int w, int h, float initWeight) {super (w, h, initWeight) } / * * {@ inheritDoc} * / public LayoutParams (ViewGroup.LayoutParams p) {super (p); / * * {@ inheritDoc} * / public LayoutParams (MarginLayoutParams source) {super (source);} / *

Fixes the child's width to * {@ link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} and the child's * height to {@ link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} * when not specified in the XML file.

* * @ param a the styled attributes set * @ param widthAttr the width attribute to fetch * @ param heightAttr the height attribute to fetch * / @ Override protected void setBaseAttributes (TypedArray a, int widthAttr, int heightAttr) {if (a.hasValue (widthAttr)) {width = a.getLayoutDimension (widthAttr, "layout_width");} else {width = WRAP_CONTENT;} if (a.hasValue (heightAttr)) {height = a.getLayoutDimension (heightAttr, "layout_height") } else {height = WRAP_CONTENT;}} / *

Interface definition for a callback to be invoked when the checked * radio button changed in this group.

* / public interface OnCheckedChangeListener {/ *

Called when the checked radio button has changed. When the * selection is cleared, checkedId is-1.

* * @ param group the group in which the checked radio button has changed * @ param checkedId the unique identifier of the newly checked radio button * / void onCheckedChanged (RadioGroup group, int checkedId);} private class CheckedStateTracker implements CompoundButton.OnCheckedChangeListener {public void onCheckedChanged (CompoundButton buttonView, boolean isChecked) {/ / prevents from infinite recursion if (mProtectFromCheckedChange) {return;} mProtectFromCheckedChange = true; if (mCheckedId! =-1) {setCheckedStateForView (mCheckedId, false);} mProtectFromCheckedChange = false Int id = buttonView.getId (); setCheckedId (id);}} / *

A pass-through listener acts upon the events and dispatches them * to another listener. This allows the table layout to set its own internal * hierarchy change listener without preventing the user to setup his.

* / private class PassThroughHierarchyChangeListener implements ViewGroup.OnHierarchyChangeListener {private ViewGroup.OnHierarchyChangeListener mOnHierarchyChangeListener; / * * {@ inheritDoc} * / public void onChildViewAdded (View parent, View child) {if (parent = = RadioGroup.this & & child instanceof RadioButton) {int id = child.getId (); / / generates an id if it's missing if (id = = View.NO_ID) {id = child.hashCode (); child.setId (id) } ((RadioButton) child) .setOnCheckedChangeListener (mChildOnCheckedChangeListener);} if (mOnHierarchyChangeListener! = null) {mOnHierarchyChangeListener.onChildViewAdded (parent, child);}} / * * {@ inheritDoc} * / public void onChildViewRemoved (View parent, View child) {if (parent = = RadioGroup.this & & child instanceof RadioButton) {(RadioButton) child) .setOnCheckedChangeListener (null);} if (mOnHierarchyChangeListener! = null) {mOnHierarchyChangeListener.onChildViewRemoved (parent, child) This is the end of the article on "how to achieve RadioGroup multi-line display by Android". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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