Android 扩大CheckBox的点击范围

以前都是通过给checkbox设置pandding的方式来解决扩大点击范围的问题

但是现在的checkbox变为AppCompatChatBox后这种方法失效了

下面介绍一种新的方法

创建一个新的CheckBox

public class LargeTouchCheckBox extends android.support.v7.widget.AppCompatCheckBox {
    private final int TOUCH_ADDITION = 0;
    private int mTouchAdditionBottom = 0;
    private int mTouchAdditionLeft = 0;
    private int mTouchAdditionRight = 0;
    private int mTouchAdditionTop = 0;
    private int mPreviousLeft = -1;
    private int mPreviousRight = -1;
    private int mPreviousBottom = -1;
    private int mPreviousTop = -1;

    public LargeTouchCheckBox(Context context) {
        super(context);
    }

    public LargeTouchCheckBox(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public LargeTouchCheckBox(Context context, AttributeSet attrs,
                                     int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {
        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.LargeTouchableAreaView);
        int addition = (int) a.getDimension(
                R.styleable.LargeTouchableAreaView_addition, TOUCH_ADDITION);
        mTouchAdditionBottom = addition;
        mTouchAdditionLeft = addition;
        mTouchAdditionRight = addition;
        mTouchAdditionTop = addition;
        mTouchAdditionBottom = (int) a.getDimension(
                R.styleable.LargeTouchableAreaView_additionBottom,
                mTouchAdditionBottom);
        mTouchAdditionLeft = (int) a.getDimension(
                R.styleable.LargeTouchableAreaView_additionLeft,
                mTouchAdditionLeft);
        mTouchAdditionRight = (int) a.getDimension(
                R.styleable.LargeTouchableAreaView_additionRight,
                mTouchAdditionRight);
        mTouchAdditionTop = (int) a.getDimension(
                R.styleable.LargeTouchableAreaView_additionTop,
                mTouchAdditionTop);
        a.recycle();
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right,
                            int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        if (left != mPreviousLeft || top != mPreviousTop
                || right != mPreviousRight || bottom != mPreviousBottom) {
            mPreviousLeft = left;
            mPreviousTop = top;
            mPreviousRight = right;
            mPreviousBottom = bottom;
            final View parent = (View) this.getParent();
            parent.setTouchDelegate(new TouchDelegate(new Rect(left
                    - mTouchAdditionLeft, top - mTouchAdditionTop, right
                    + mTouchAdditionRight, bottom + mTouchAdditionBottom), this));
        }
    }

}

在Styles.xml里面加入

布局文件的样子

 

其实总体思路还是类似于pandding的方式

这里需要注意的一点就是：

LargeTouchCheckBox需要在外层套一个layout，layout的大小就是你想要的点击范围（宽=checkbox.width+leftpadding+rightpadding，高以此类推）

注意一下代码：

 final View parent = (View) this.getParent();
 parent.setTouchDelegate(new TouchDelegate(new Rect(left
                    - mTouchAdditionLeft, top - mTouchAdditionTop, right
                    + mTouchAdditionRight, bottom + mTouchAdditionBottom), this));

由于setTouchDelegate，所以一个viewgroup下只能有一个控件设置TouchDelegate，其他控件如果也想设置TouchDelegate只能在控件外层嵌套一层无用的FrameLayout。