android 底部tabs切换，支持多层嵌套RadioButton的RadioGroup

前言

非常喜欢用RadioButton+RadioGroup做Tabs，能自动处理选中等效果，但是自带的RadioGroup不支持嵌套RadioButton（从源码可看出仅仅是判断子控件是不是RadioButton），本文参考RadioGroup修改了一个支持嵌套CompoundButton的控件，非常实用。 

原文引自：

http://www.cnblogs.com/over140/p/3795877.html

正文

/** * 支持嵌套CompoundButton的NestRadioGroup *  * @author 农民伯伯 http://www.cnblogs.com/over140/ * */public class NestRadioGroup 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 NestRadioGroup(Context context) {        super(context);        init();    }    /**     * {@inheritDoc}     */    public NestRadioGroup(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    private void init() {        mCheckedId = View.NO_ID;        setOrientation(HORIZONTAL);        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 != View.NO_ID) {            mProtectFromCheckedChange = true;            setCheckedStateForView(mCheckedId, true);            mProtectFromCheckedChange = false;            setCheckedId(mCheckedId);        }    }    /** 递归查找具有选中属性的子控件 */    private static CompoundButton findCheckedView(View child) {        if (child instanceof CompoundButton)            return (CompoundButton) child;        if (child instanceof ViewGroup) {            ViewGroup group = (ViewGroup) child;            for (int i = 0, j = group.getChildCount(); i < j; i++) {                CompoundButton check = findCheckedView(group.getChildAt(i));                if (check != null)                    return check;            }        }        return null;//没有找到    }    @Override    public void addView(View child, int index, ViewGroup.LayoutParams params) {        final CompoundButton view = findCheckedView(child);        if (view != null) {            if (view.isChecked()) {                mProtectFromCheckedChange = true;                if (mCheckedId != -1) {                    setCheckedStateForView(mCheckedId, false);                }                mProtectFromCheckedChange = false;                setCheckedId(view.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(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;        if (mOnCheckedChangeListener != null) {            mOnCheckedChangeListener.onCheckedChanged(this, mCheckedId);        }    }    private void setCheckedStateForView(int viewId, boolean checked) {        View checkedView = findViewById(viewId);        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     *     * @see #check(int)     * @see #clearCheck()     *     * @attr ref android.R.styleable#NestRadioGroup_checkedButton     */    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 NestRadioGroup.LayoutParams(getContext(), attrs);    }    /**     * {@inheritDoc}     */    @Override    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {        return p instanceof NestRadioGroup.LayoutParams;    }    @Override    protected LinearLayout.LayoutParams generateDefaultLayoutParams() {        return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);    }    /**     * <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);        }        /**         * {@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(NestRadioGroup 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);        }    }    /**     * <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}         */        @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)    public void onChildViewAdded(View parent, View child) {            if (parent == NestRadioGroup.this) {                CompoundButton view = findCheckedView(child);//查找子控件                if (view != null) {                    int id = view.getId();                    // generates an id if it's missing                    if (id == View.NO_ID && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {                        id = View.generateViewId();                        view.setId(id);                    }                    view.setOnCheckedChangeListener(mChildOnCheckedChangeListener);                }            }            if (mOnHierarchyChangeListener != null) {                mOnHierarchyChangeListener.onChildViewAdded(parent, child);            }        }        /**         * {@inheritDoc}         */        public void onChildViewRemoved(View parent, View child) {            if (parent == NestRadioGroup.this) {                CompoundButton view = findCheckedView(child);//查找子控件                if (view != null) {                    view.setOnCheckedChangeListener(null);                }            }            if (mOnHierarchyChangeListener != null) {                mOnHierarchyChangeListener.onChildViewRemoved(parent, child);            }        }    }

代码说明

代码主要是仿照RadioGroup改写，主要是findCheckedView方法递归查找具有选中属性的子控件。

用法

<com.xxx.ui.view.NestRadioGroup            android:id="@+id/main_radio"            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:gravity="center"            android:orientation="horizontal" >            <RadioButton                android:id="@+id/radio_button0"                android:layout_width="0dip"                android:layout_height="wrap_content"                android:layout_weight="1.0"                android:checked="true"                android:text="@string/bottom_feed" />            <RadioButton                android:id="@+id/radio_button1"                android:layout_width="0dip"                android:layout_height="wrap_content"                android:layout_weight="1.0"                android:text="@string/bottom_square" />            <RelativeLayout                android:layout_width="0dip"                android:layout_height="fill_parent"                android:layout_weight="1.0"                android:orientation="horizontal" >                <RadioButton                    android:id="@+id/radio_button2"                    style="@style/title_tab_text_style"                    android:layout_width="wrap_content"                    android:layout_height="wrap_content"                    android:layout_centerInParent="true"                    android:text="@string/bottom_message" />                <ImageView                    android:id="@+id/new_message_tips"                    android:layout_width="wrap_content"                    android:layout_height="wrap_content"                    android:layout_marginTop="10dip"                    android:layout_toRightOf="@+id/radio_button2"                    android:src="@drawable/news_tips_red" />            </RelativeLayout>        </com.xxx.ui.view.NestRadioGroup>

代码说明 

1、实现非常常见的Tabs效果，结合ViewPager来使用，new_message_tips可以是一个类似微信右上角的小红圈，用来提醒有新的消息。 

2、View.generateViewId需要4.2以上才能使用，所以最好自己设置id