android自定義RadioGroup可以添加多種布局的實現方法

2020-04-11 12:03:57

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android自帶的RadioGroup是繼承自LinearLayout，如果布局的時候不是直接寫radiobutton,即radiobutton外面還包了一層容器，這時分組是不成功的，因為查找不到radiobutton,如果要實現這種效果呢，于是看了RadioGroup的源碼，發現問題在于addView方法和自定義的PassThroughHierarchyChangeListener；

下面就這兩個地方動手腳，先拷貝源碼，然后去掉RadioGroup(Context context, AttributeSet attrs) 中的方法，我新增了一個方法，查找viewGroup控件中的radioButton

復制代碼代碼如下:

/** 查找radioButton控件 */
    public RadioButton findRadioButton(ViewGroup group) {
        RadioButton resBtn = null;
        int len = group.getChildCount();
        for (int i = 0; i < len; i++) {
            if (group.getChildAt(i) instanceof RadioButton) {
                resBtn = (RadioButton) group.getChildAt(i);
            } else if (group.getChildAt(i) instanceof ViewGroup) {
                findRadioButton((ViewGroup) group.getChildAt(i));
            }
        }
        return resBtn;
    }

addView的實現如下：

復制代碼代碼如下:

@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) { //這里是我添加的代碼
            final RadioButton button = findRadioButton((ViewGroup) child);
            if (button.isChecked()) {
                mProtectFromCheckedChange = true;
                if (mCheckedId != -1) {
                    setCheckedStateForView(mCheckedId, false);
                }
                mProtectFromCheckedChange = false;
                setCheckedId(button.getId());
            }
        }

super.addView(child, index, params);
}

然后在自定義的PassThroughHierarchyChangeListener中修改：

復制代碼代碼如下:

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   //這里是我添加的代碼
                    && child instanceof ViewGroup) {
                RadioButton btn = findRadioButton((ViewGroup) child);
                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) {
                findRadioButton((ViewGroup) child).setOnCheckedChangeListener(
                        null);
            }
            if (mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewRemoved(parent, child);
            }
        }
    }

做好了上面的步驟，下面布局就可以按照自己的意思來了，并且分組效果也不會影響

下面我的布局文件demo:

復制代碼代碼如下:

<com.huaheng.wy.view.MyRadioGroup
 android:id="@+id/rg"
 android:layout_width="fill_parent"
 android:layout_height="65dp"
 android:layout_alignParentBottom="true"
 android:background="@drawable/yst_i_bottom"
 android:orientation="horizontal" >

所有實現代碼都在這里，下面我就把自定義的radioGroup的代碼，完整的貼出來

復制代碼代碼如下:

/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package com.huaheng.wy.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CompoundButton;
import android.widget.LinearLayout;
import android.widget.RadioButton;

public class MyRadioGroup 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 MyRadioGroup(Context context) {
        super(context);
        setOrientation(VERTICAL);
        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) {
            final RadioButton button = findRadioButton((ViewGroup) child);
            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 RadioButton findRadioButton(ViewGroup group) {
 RadioButton resBtn = null;
 int len = group.getChildCount();
 for (int i = 0; i < len; i++) {
 if (group.getChildAt(i) instanceof RadioButton) {
 resBtn = (RadioButton) group.getChildAt(i);
 } else if (group.getChildAt(i) instanceof ViewGroup) {
 findRadioButton((ViewGroup) group.getChildAt(i));
 }
 }
 return resBtn;
 }

/**
 * 
 * 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;
        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);
        }
    }

/**
 * 
 * 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
 *
 * @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 MyRadioGroup.LayoutParams(getContext(), attrs);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof MyRadioGroup.LayoutParams;
    }

    @Override
    protected LinearLayout.LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT);
    }

/**
 * 
 * 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.
 * 
 *
 * 
 * See {@link android.R.styleable#LinearLayout_Layout LinearLayout
 * Attributes} for a list of all child view attributes that this class
 * supports.
 * 
 *
 */
 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
 */
 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);
        }
    }

/**
 * 
 * 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;

        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) {
                RadioButton btn = findRadioButton((ViewGroup) child);
                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);
            }
        }