android自定义RadioGroup实现继承多种布局_android radiogroup 布局

作者：不正经 | 2024-06-18 04:43:35

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android radiogroup 布局

android自带的RadioGroup是继承自LinearLayout，如果布局的时候不是直接在RadioGroup中radiobutton,即radiobutton的父布局不是RadioGroup，这时是查找不到radiobutton的。为了更方便布局，往往radioButton的外面还会包裹一层布局的。如果要实现这种效果，可以自定义一个RadioGroup,于是看了RadioGroup的源码，发现问题在于addView方法和自定义的PassThroughHierarchyChangeListener；

LinearLayout,ConstraintLayout等布局都是继承自viewGroup,要查询它们下面的RadioButton，则在addView方法中增加查询代码。

先拷贝源码，然后去掉RadioGroup(Context context, AttributeSet attrs) 中的方法，新增了一个方法，查找viewGroup控件中的radioButton。


    /** 查找radioButton控件
	因为往往不是只有一个RadioButton，所以返回一个集合，并且当布局下没有RadioButton时后面也不会报错*/
    public List<RadioButton> findRadioButton(ViewGroup group) {
        List<RadioButton> resBtns=new ArrayList<>();
        int len = group.getChildCount();
        for (int i = 0; i < len; i++) {
            if (group.getChildAt(i) instanceof RadioButton) {
                resBtns.add((RadioButton) group.getChildAt(i));
            } else if (group.getChildAt(i) instanceof ViewGroup) {
                findRadioButton((ViewGroup) group.getChildAt(i));
            }
        }
        return resBtns;
    }

然后在addView方法中使用


  @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());
            }
        } else if (child instanceof ViewGroup) {//自己的，可查询viewGroup内部的radioButton
            final List<RadioButton> buttons = findRadioButton((ViewGroup) child);
            for(RadioButton button:buttons) {
                if (button.isChecked()) {
                    mProtectFromCheckedChange = true;
                    if (mCheckedId != -1) {
                        setCheckedStateForView(mCheckedId, false);
                    }
                    mProtectFromCheckedChange = false;
                    setCheckedId(button.getId());
                }
            }
        }
 
        super.addView(child, index, params);
    }

可以查询到radioButton了，还需要对其进行点击，移除等监听方法、


    private class PassThroughHierarchyChangeListener implements
            ViewGroup.OnHierarchyChangeListener {
        private ViewGroup.OnHierarchyChangeListener mOnHierarchyChangeListener;
 
        public void onChildViewAdded(View parent, View child) {
            if (parent == MyRadioGroup.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);
            } else if (parent == MyRadioGroup.this
                    && child instanceof ViewGroup) {
                List<RadioButton> btns = findRadioButton((ViewGroup) child);
                for(RadioButton btn:btns) {
                    int id = btn.getId();
                    // generates an id if it's missing
                    if (id == View.NO_ID) {
                        id = btn.hashCode();
                        btn.setId(id);
                    }
                    btn.setOnCheckedChangeListener(mChildOnCheckedChangeListener);
                }
            }
 
            if (mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewAdded(parent, child);
            }
        }
 
        public void onChildViewRemoved(View parent, View child) {
            if (parent == MyRadioGroup.this && child instanceof RadioButton) {
                ((RadioButton) child).setOnCheckedChangeListener(null);
            } else if (parent == MyRadioGroup.this
                    && child instanceof ViewGroup) {
 
                List<RadioButton> btns=findRadioButton((ViewGroup) child);
                for(RadioButton btn:btns){
                    btn.setOnCheckedChangeListener(
                            null);
                }
            }
            if (mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewRemoved(parent, child);
            }
        }
    }

其他的可以按照自己的意思来完成布局。这里我继承的是ConstraintLayout，也可以继承其他的布局，看需要。

下面是全部的代码


 
import android.content.Context;
import android.content.res.TypedArray;
import android.support.constraint.ConstraintLayout;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CompoundButton;
import android.widget.RadioButton;
 
import java.util.ArrayList;
import java.util.List;
 
 
/**
 * Created by 墨 on 2018/1/5.
 */
 
public class MyRadioGroup extends ConstraintLayout {
    // 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 MyRadioGroup(Context context) {
        super(context);
        init();
    }
 
    public MyRadioGroup(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }
 
    private void init() {
        mChildOnCheckedChangeListener = new CheckedStateTracker();
        mPassThroughListener = new PassThroughHierarchyChangeListener();
        super.setOnHierarchyChangeListener(mPassThroughListener);
    }
 
    @Override
    public void setOnHierarchyChangeListener(OnHierarchyChangeListener listener) {
        // the user listener is delegated to our pass-through listener
        mPassThroughListener.mOnHierarchyChangeListener = listener;
    }
 
    @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(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());
            }
        } else if (child instanceof ViewGroup) {//自己的，可查询group内部的radioButton
            final List<RadioButton> buttons = findRadioButton((ViewGroup) child);
            for(RadioButton button:buttons) {
                if (button.isChecked()) {
                    mProtectFromCheckedChange = true;
                    if (mCheckedId != -1) {
                        setCheckedStateForView(mCheckedId, false);
                    }
                    mProtectFromCheckedChange = false;
                    setCheckedId(button.getId());
                }
            }
        }
 
        super.addView(child, index, params);
    }
 
    /** 查找radioButton控件 */
    public List<RadioButton> findRadioButton(ViewGroup group) {
        List<RadioButton> resBtns=new ArrayList<>();
        int len = group.getChildCount();
        for (int i = 0; i < len; i++) {
            if (group.getChildAt(i) instanceof RadioButton) {
                resBtns.add((RadioButton) group.getChildAt(i));
            } else if (group.getChildAt(i) instanceof ViewGroup) {
                findRadioButton((ViewGroup) group.getChildAt(i));
            }
        }
        return resBtns;
    }
 
    /**
     * <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 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
     *
     * @see #check(int)
     * @see #clearCheck()
     */
    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 MyRadioGroup.LayoutParams(getContext(), attrs);
    }
 
    /**
     * {@inheritDoc}
     */
    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof MyRadioGroup.LayoutParams;
    }
 
    @Override
    protected ConstraintLayout.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>
     * Attributes} for a list of all child view attributes that this class
     * supports.
     * </p>
     *
     */
    public static class LayoutParams extends ConstraintLayout.LayoutParams {
        /**
         * {@inheritDoc}
         */
        public LayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
        }
 
        /**
         * {@inheritDoc}
         */
        public LayoutParams(int w, int h) {
            super(w, h);
        }
 
 
 
        /**
         * {@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(MyRadioGroup 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;
 
        public void onChildViewAdded(View parent, View child) {
            if (parent == MyRadioGroup.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);
            } else if (parent == MyRadioGroup.this
                    && child instanceof ViewGroup) {
                List<RadioButton> btns = findRadioButton((ViewGroup) child);
                for(RadioButton btn:btns) {
                    int id = btn.getId();
                    // generates an id if it's missing
                    if (id == View.NO_ID) {
                        id = btn.hashCode();
                        btn.setId(id);
                    }
                    btn.setOnCheckedChangeListener(mChildOnCheckedChangeListener);
                }
            }
 
            if (mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewAdded(parent, child);
            }
        }
 
        public void onChildViewRemoved(View parent, View child) {
            if (parent == MyRadioGroup.this && child instanceof RadioButton) {
                ((RadioButton) child).setOnCheckedChangeListener(null);
            } else if (parent == MyRadioGroup.this
                    && child instanceof ViewGroup) {
 
                List<RadioButton> btns=findRadioButton((ViewGroup) child);
                for(RadioButton btn:btns){
                    btn.setOnCheckedChangeListener(
                            null);
                }
            }
            if (mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewRemoved(parent, child);
            }
        }
    }
}

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