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如何使RadioGroup支持RadioButton任意嵌套

在实际的项目中,我们经常都是RadioButtonRadioGroup一起配合使用。RadioGroup是单选组合框,可以容纳多个RadioButton的容器。在没有RadioGroup的情况下,RadioButton可以全部都选中;当多个RadioButtonRadioGroup包含的情况下,RadioButton只可以选中一个。并用setOnCheckedChangeListener来对单选按钮进行监听。

RadioButton和RadioGroup的关系:

  • RadioButton表示单个圆形单选框,而RadioGroup是可以容纳多个RadioButton的容器。
  • 每个RadioGroup中的RadioButton同时只能有一个被选中。
  • 不同的RadioGroup中的RadioButton互不相干,即如果组A中有一个选中了,组B中依然可以有一个被选中。
  • 一般情况下,一个RadioGroup中至少有2个RadioButton。
  • 一般情况下,一个RadioGroup中的RadioButton默认会有一个被选中,并建议您将它放在RadioGroup中的起始位置。

实际使用的问题:

如何使RadioGroup支持RadioButton任意嵌套

device-2017-02-17-161810.png

如何使RadioGroup支持RadioButton任意嵌套

device-2017-02-17-161658.png

众所周知,RadioGroup只能够通过设置radioGroup.setOrientation()实现纵向或者横向排列,并且只能是一列或者一行,并且RadioGroup中还只能直接放RadioButton,但在实际项目中我们大都是需要实现上面的效果,所以简单的封装了一个,取名为:XRadioGroup

XRadioGroup的实现

RadioGroup源码分析

本着求知好学的心态,首先研究一下RadioGroup的实现代码,为什么不能实现上面的效果(源码中省略了部分代码)。

public class RadioGroup extends LinearLayout {  /**  * {@inheritDoc}  */ public RadioGroup(Context context) {     super(context);     setOrientation(VERTICAL);     init(); }  @Override public void addView(View child, int index, ViewGroup.LayoutParams params) {     if (child instanceof RadioButton) {         final RadioButton button = (RadioButton) child;         if (button.isChecked()) {             mProtectFromCheckedChange = true;             if (mCheckedId != -1) {                 setCheckedStateForView(mCheckedId, false);             }             mProtectFromCheckedChange = false;             setCheckedId(button.getId());         }     }      super.addView(child, index, params); }  /**  * <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 id the unique id of the radio button to select in this group  *  * @see #getCheckedRadioButtonId()  * @see #clearCheck()  */ public void check(@IdRes 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(@IdRes int id) {     mCheckedId = id;     if (mOnCheckedChangeListener != null) {         mOnCheckedChangeListener.onCheckedChanged(this, mCheckedId);     } }  private void setCheckedStateForView(int viewId, boolean checked) {     View checkedView = findViewById(viewId);     if (checkedView != null && checkedView instanceof RadioButton) {         ((RadioButton) checkedView).setChecked(checked);     } }  /**  * <p>Clears the selection. When the selection is cleared, no radio button  * in this group is selected and {@link #getCheckedRadioButtonId()} returns  * null.</p>  *  * @see #check(int)  * @see #getCheckedRadioButtonId()  */ public void clearCheck() {     check(-1); }  /**  * <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(OnCheckedChangeListener listener) {     mOnCheckedChangeListener = listener; }  /**  * <p>This set of layout parameters defaults the width and the height of  * the children to {@link #WRAP_CONTENT} when they are not specified in the  * XML file. Otherwise, this class ussed the value read from the XML file.</p>  *  * <p>See  * {@link android.R.styleable#LinearLayout_Layout LinearLayout Attributes}  * for a list of all child view attributes that this class supports.</p>  *  */ public static class LayoutParams extends LinearLayout.LayoutParams {     /**      * {@inheritDoc}      */     public LayoutParams(Context c, AttributeSet attrs) {         super(c, attrs);     }  /**  * <p>Interface definition for a callback to be invoked when the checked  * radio button changed in this group.</p>  */ public interface OnCheckedChangeListener {     /**      * <p>Called when the checked radio button has changed. When the      * selection is cleared, checkedId is -1.</p>      *      * @param group the group in which the checked radio button has changed      * @param checkedId the unique identifier of the newly checked radio button      */     public void onCheckedChanged(RadioGroup group, @IdRes 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);     } }  /**  * <p>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.</p>  */ 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 = View.generateViewId();                 child.setId(id);             }             ((RadioButton) child).setOnCheckedChangeWidgetListener(                     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).setOnCheckedChangeWidgetListener(null);         }          if (mOnHierarchyChangeListener != null) {             mOnHierarchyChangeListener.onChildViewRemoved(parent, child);         }     }   } }

源码中可以发现RadioGroup是继承至LinearLayout,因为LinearLayout的特性缘故,所以RadioGroup也就只能够使其子类实现纵向或横向排列。再看为什么只能够直接包裹RadioButton,在public void addView(View child, int index, ViewGroup.LayoutParams params)方法中可以发现只判断了直接子类,所以要是RadioGroup中包含了其他ViewGroup,即使ViewGroup中包含了RadioButton也不会处理。现在问题就清楚了,需要解决的就是让ViewGroup中的RadioButton也能够被同时处理。

XRadioGroup源码分析

public class XRadioGroup 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;  public XRadioGroup(Context context) {     super(context);     init(); }  public XRadioGroup(Context context, AttributeSet attrs) {     super(context, attrs);     init(); }  public XRadioGroup(Context context, AttributeSet attrs, int defStyleAttr) {     super(context, attrs, defStyleAttr);     init(); }  @TargetApi(Build.VERSION_CODES.LOLLIPOP) public XRadioGroup(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {     super(context, attrs, defStyleAttr, defStyleRes);     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);     } }  private void setViewState(View child) {     if (child instanceof RadioButton) {         final RadioButton button = (RadioButton) child;         if (button.isChecked()) {             mProtectFromCheckedChange = true;             if (mCheckedId != -1) {                 setCheckedStateForView(mCheckedId, false);             }             mProtectFromCheckedChange = false;             setCheckedId(button.getId());         }     } else if (child instanceof ViewGroup) {         ViewGroup view = (ViewGroup) child;         for (int i = 0; i < view.getChildCount(); i++) {             setViewState(view.getChildAt(i));         }     } }  @Override public void addView(View child, int index, ViewGroup.LayoutParams params) {     setViewState(child);     super.addView(child, index, params); }  /**  * <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 id the unique id of the radio button to select in this group  * @see #getCheckedRadioButtonId()  * @see #clearCheck()  */ public void check(@IdRes 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(@IdRes int id) {     mCheckedId = id;     if (mOnCheckedChangeListener != null) {         mOnCheckedChangeListener.onCheckedChanged(this, mCheckedId);     } }  private void setCheckedStateForView(int viewId, boolean checked) {     View checkedView = findViewById(viewId);     if (checkedView != null && checkedView instanceof RadioButton) {         ((RadioButton) 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(int)  * @see #clearCheck()  */ @IdRes public int getCheckedRadioButtonId() {     return mCheckedId; }  /**  * <p>Clears the selection. When the selection is cleared, no radio button  * in this group is selected and {@link #getCheckedRadioButtonId()} returns  * null.</p>  *  * @see #check(int)  * @see #getCheckedRadioButtonId()  */ public void clearCheck() {     check(-1); }  /**  * <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(OnCheckedChangeListener listener) {     mOnCheckedChangeListener = listener; }  /**  * {@inheritDoc}  */ @Override public LayoutParams generateLayoutParams(AttributeSet attrs) {     return new XRadioGroup.LayoutParams(getContext(), attrs); }  /**  * {@inheritDoc}  */ @Override protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {     return p instanceof XRadioGroup.LayoutParams; }  @Override protected LinearLayout.LayoutParams generateDefaultLayoutParams() {     return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); }  @Override public CharSequence getAccessibilityClassName() {     return XRadioGroup.class.getName(); }  /**  * <p>This set of layout parameters defaults the width and the height of  * the children to {@link #WRAP_CONTENT} when they are not specified in the  * XML file. Otherwise, this class ussed the value read from the XML file.</p>  * <p/>  * <p>See  * {@link  LinearLayout Attributes}  * for a list of all child view attributes that this class supports.</p>  */ 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);     }      /**      * <p>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.</p>      *      * @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;         }     } }  /**  * <p>Interface definition for a callback to be invoked when the checked  * radio button changed in this group.</p>  */ public interface OnCheckedChangeListener {     /**      * <p>Called when the checked radio button has changed. When the      * selection is cleared, checkedId is -1.</p>      *      * @param group     the group in which the checked radio button has changed      * @param checkedId the unique identifier of the newly checked radio button      */     public void onCheckedChanged(XRadioGroup group, @IdRes 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);     } }  /**  * <p>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.</p>  */ private class PassThroughHierarchyChangeListener implements         ViewGroup.OnHierarchyChangeListener {     private ViewGroup.OnHierarchyChangeListener mOnHierarchyChangeListener;      /**      * {@inheritDoc}      */     public void onChildViewAdded(View parent, View child) {         setListener(child);          if (mOnHierarchyChangeListener != null) {             mOnHierarchyChangeListener.onChildViewAdded(parent, child);         }     }      /**      * {@inheritDoc}      */     public void onChildViewRemoved(View parent, View child) {         removeListener(child);          if (mOnHierarchyChangeListener != null) {             mOnHierarchyChangeListener.onChildViewRemoved(parent, child);         }     } }  /**  * 设置监听  *  * @param child  */ private void setListener(View child) {     if (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);     } else if (child instanceof ViewGroup) {         ViewGroup view = (ViewGroup) child;         for (int i = 0; i < view.getChildCount(); i++) {             setListener(view.getChildAt(i));         }     } }   /**  * 移除监听  *  * @param child  */ private void removeListener(View child) {     if (child instanceof RadioButton) {         ((RadioButton) child).setOnCheckedChangeListener(null);     } else if (child instanceof ViewGroup) {         ViewGroup view = (ViewGroup) child;         for (int i = 0; i < view.getChildCount(); i++) {             removeListener(view.getChildAt(i));         }     }   } }

public void addView(View child, int index, ViewGroup.LayoutParams params)方法中调用的private void setViewState(View child)setViewState通过递归来实现设置RadioButton的初始状态。在PassThroughHierarchyChangeListener中增加了private void setListener(View child)private void removeListener(View child)分别用来处理设置监听和移除监听。

详细的代码可以查看Github:XRadioGroup

如何使用

java代码中使用方式与android.widget.RadioGroup完全一致

XRadioGroup xRadioGroup = (XRadioGroup) findViewById(R.id.xRadioGroup); xRadioGroup.setOnCheckedChangeListener(new XRadioGroup.OnCheckedChangeListener() {      @Override      public void onCheckedChanged(XRadioGroup group, @IdRes int checkedId) {           Log.d("TAG", checkedId + "is checked");      }  });

在xml中你可以里面嵌套使用

<me.shihao.library.XRadioGroup         android:id="@+id/xRadioGroup"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:orientation="vertical">          <RelativeLayout             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_centerHorizontal="true"             android:layout_centerVertical="true">              <RadioButton                 android:id="@+id/radioButton"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_alignParentLeft="true"                 android:layout_alignParentStart="true"                 android:layout_alignParentTop="true"                 android:checked="true"                 android:text="New RadioButton"/>              <RadioButton                 android:id="@+id/radioButton2"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_alignParentEnd="true"                 android:layout_alignParentRight="true"                 android:layout_alignParentTop="true"                 android:layout_gravity="center_horizontal"                 android:text="New RadioButton"/>              <RadioButton                 android:id="@+id/radioButton3"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_alignParentLeft="true"                 android:layout_alignParentStart="true"                 android:layout_below="@+id/radioButton"                 android:layout_gravity="center_horizontal"                 android:text="New RadioButton"/>              <RadioButton                 android:id="@+id/radioButton4"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_alignParentEnd="true"                 android:layout_alignParentRight="true"                 android:layout_alignTop="@+id/radioButton3"                 android:text="New RadioButton"/>              <RadioButton                 android:id="@+id/radioButton5"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_below="@+id/radioButton3"                 android:layout_centerHorizontal="true"                 android:text="New RadioButton"/>              <RadioButton                 android:id="@+id/radioButton6"                 android:layout_width="wrap_content"                 android:layout_height="wrap_content"                 android:layout_alignLeft="@+id/radioButton5"                 android:layout_alignStart="@+id/radioButton5"                 android:layout_below="@+id/radioButton5"                 android:text="New RadioButton"/>         </RelativeLayout>     </me.shihao.library.XRadioGroup>

详细的使用代码可以查看Github:XRadioGroup

gradle快速集成

allprojects {   repositories {        ...       maven { url 'https://www.jitpack.io' }   } }  dependencies {   compile 'com.github.fodroid:XRadioGroup:v1.1' }

如果你觉得有用,请在Github不吝给我一个Star,非常感谢。


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