自定义控件之TagGroup

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转载请注明出处：http://blog.csdn.net/crazy1235/article/details/74907150

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标签瀑布流布局！

实现方式有很多种。

• 继承LinearLayout

• 继承ViewGroup

• 继承别的布局…

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继承LinearLayout

继承LinearLayout相对来说，实现比较简单！不需要自己处理onMeasure() 和 onLayout() 函数！

整个布局设置成 LinearLayout.VERTICAL 排列模式！

然后每一行作为一个子LinearLayout，通过 addView(LinearLayout)进去！子LinearLayout是 LinearLayout.HORIZONTAL 排列模式！

当一行addView(tag)的时候超过了最外层的宽度，则需要另起一行！

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继承ViewGroup

继承ViewGroup的情况，比较麻烦。需要自己处理onMeasure()和onLayout() ！

自定义一套TagGroup 需要注意的地方：

• 标签的margin值

• 标签的padding值

• TagGroup的padding值

• 标签的行间距

• 标签的列间距

• 字体大小

• 字体颜色

• 标签按下的状态

• 选中标签

• ……

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SuperTagGroup

首先是，属性定义：

    <declare-styleable name="SuperTagGroup">

        <attr name="horizontal_spacing" format="dimension" />
        <attr name="vertical_spacing" format="dimension" />
        <attr name="tag_horizontal_padding" format="dimension" />
        <attr name="tag_vertical_padding" format="dimension" />
        <attr name="tag_text_size" format="dimension" />
        <attr name="tag_text_color" format="color" />
        <attr name="tag_corner_radius" format="dimension" />
        <attr name="tag_border_width" format="dimension" />
        <attr name="tag_border_color" format="color" />
        <attr name="tag_border_checked_color" format="color" />
        <attr name="tag_bg_color" format="color" />
        <attr name="tag_bg_checked_color" format="color" />
        <attr name="tag_bg_drawable" format="reference" />
        <attr name="max_selected_count" format="integer" />

    </declare-styleable>

然后在构造函数中，读取出这些属性

public SuperTagGroup(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.SuperTagGroup, defStyleAttr, R.style.SuperTagGroup);

        horizontalSpace = ta.getDimension(R.styleable.SuperTagGroup_horizontal_spacing, 0);
        verticalSpace = ta.getDimension(R.styleable.SuperTagGroup_vertical_spacing, 0);

        horizontalPadding = (int) ta.getDimension(R.styleable.SuperTagGroup_tag_horizontal_padding, 0);
        verticalPadding = (int) ta.getDimension(R.styleable.SuperTagGroup_tag_vertical_padding, 0);

        textSize = ta.getDimension(R.styleable.SuperTagGroup_tag_text_size, 0);
        textColor = ta.getColor(R.styleable.SuperTagGroup_tag_text_color, 0);

        cornerRadius = ta.getDimension(R.styleable.SuperTagGroup_tag_corner_radius, 0);

        borderWidth = ta.getDimension(R.styleable.SuperTagGroup_tag_border_width, 0);
        borderColor = ta.getColor(R.styleable.SuperTagGroup_tag_border_color, 0);
        tagBorderCheckedColor = ta.getColor(R.styleable.SuperTagGroup_tag_border_checked_color, 0);

        tagBgColor = ta.getColor(R.styleable.SuperTagGroup_tag_bg_color, 0);
        tagBgCheckedColor = ta.getColor(R.styleable.SuperTagGroup_tag_bg_checked_color, 0);

        tagBgDrawable = ta.getResourceId(R.styleable.SuperTagGroup_tag_bg_drawable, 0);

        maxSelectedNum = ta.getInt(R.styleable.SuperTagGroup_max_s    ta.recycle();

        init();
    }

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接着就是重要的onMeasure() 函数

用来对自身布局和子view进行测量，得到测量宽高来进行设置

主要就是针对每个子view进行测量，注意过程中要加上我们设置的padding值，和spacing值！

针对各个子view测量完毕之后，再加上布局的padding值，即可得到布局的宽高！

@Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Log.d("SuperTagGroup", "onMeasure");
        // width size & mode
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);

        // height size & mode
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        // padding
        int paddingLeft = getPaddingLeft();
        int paddingTop = getPaddingTop();
        int paddingRight = getPaddingRight();
        int paddingBottom = getPaddingBottom();

        // the width & height final result
        int resultWidth = 0;
        int resultHeight = 0;

        int lineWidth = 0;
        int lineHeight = 0;

        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            if (child.getVisibility() == View.GONE) {
                continue;
            }

            if (!(child instanceof SuperTagView)) {
                throw new IllegalStateException("SuperTagGroup can only has SuperTagView child");
            }

            // measure child
            measureChild(child, widthMeasureSpec, heightMeasureSpec);

            // 这里要记得加上子view的margin值
//            MarginLayoutParams childLayoutParams = (MarginLayoutParams) child.getLayoutParams();
            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();

            lineHeight = Math.max(childHeight, lineHeight);

            if (lineWidth + childWidth > widthSize - paddingLeft - paddingRight) { // 需要换一行
                resultWidth = Math.max(resultWidth, lineWidth); // 每一行都进行比较，最终得到最宽的值
                resultHeight += verticalSpace + lineHeight;

                lineWidth = (int) (childWidth + horizontalSpace); // 新的一行的宽度
                lineHeight = childHeight; // 新的一行的高度
            } else {
                // 当前行的宽度
                lineWidth += childWidth + horizontalSpace;
                // 当前行最大的高度
                lineHeight = Math.max(lineHeight, childHeight);
            }

            // 最后一个, 需要再次比较宽
            if (i == getChildCount() - 1) {
                resultWidth = Math.max(resultWidth, lineWidth);
            }
        }

        resultWidth += paddingRight + paddingLeft;
        // 布局最终的高度
        resultHeight += lineHeight + paddingBottom + paddingTop;

        setMeasuredDimension(widthMode == MeasureSpec.EXACTLY ? widthSize : resultWidth, heightMode == MeasureSpec.EXACTLY ? heightSize : resultHeight);
    }

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onLayout() 是用来确定各个子view的四个点的位置

@Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        // padding
        int paddingLeft = getPaddingLeft();
        int paddingTop = getPaddingTop();
        int paddingRight = getPaddingRight();

        int lineHeight = 0;

        // 子view的左侧和顶部位置
        int childLeft = paddingLeft;
        int childTop = paddingTop;

        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            if (child.getVisibility() == View.GONE) {
                continue;
            }

            // 找到最后一个append tag
            if (((SuperTagView) child).isAppendTag()) {
                if (appendTagIndex != -1 && latestAppendTagView != null) {
                    latestAppendTagView.setAppendTag(false);
                }
                appendTagIndex = i;
                ((SuperTagView) child).setAppendTag(true);
                latestAppendTagView = (SuperTagView) child;
            }

            int childWidth = child.getMeasuredWidth();
            int childHeight = child.getMeasuredHeight();

            lineHeight = Math.max(lineHeight, childHeight);

            if (childLeft + childWidth + paddingRight > getWidth()) { // 需要换行
                childLeft = paddingLeft;
                childTop += lineHeight + verticalSpace;

                lineHeight = childHeight;
            }

            // 布局
            child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);

            // 计算下一个子view X的位置
            childLeft += childWidth + horizontalSpace;
        }
    }

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SuperTagView

针对SuperTagGroup设计了这样一个自定义子view。可以直接在xml布局中添加tag，当然也可以动态的添加删除tag！

还是首先来看 属性定义。

<declare-styleable name="SuperTagView">

        <attr name="is_append_tag" format="boolean" />
        <attr name="horizontal_padding" format="dimension" />
        <attr name="vertical_padding" format="dimension" />
        <attr name="corner_radius" format="dimension" />
        <attr name="border_width" format="dimension" />
        <attr name="border_color" format="color" />
        <attr name="border_checked_color" format="color" />
        <attr name="bg_color" format="color" />
        <attr name="bg_checked_color" format="color" />

    </declare-styleable>

然后在构造函数中读取属性

public SuperTagView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.SuperTagView, defStyleAttr, R.style.SuperTagGroup_TagView);

        isAppendTag = ta.getBoolean(R.styleable.SuperTagView_is_append_tag, false);

        horizontalPadding = (int) ta.getDimension(R.styleable.SuperTagView_horizontal_padding, SuperTagUtil.dp2px(context, SuperTagUtil.DEFAULT_HORIZONTAL_PADDING));
        verticalPadding = (int) ta.getDimension(R.styleable.SuperTagView_vertical_padding, SuperTagUtil.dp2px(context, SuperTagUtil.DEFAULT_VERTICAL_PADDING));

        cornerRadius = ta.getDimension(R.styleable.SuperTagView_corner_radius, 0);

        borderWidth = ta.getDimension(R.styleable.SuperTagView_border_width, 0);

        borderColor = ta.getColor(R.styleable.SuperTagView_border_color, SuperTagUtil.DEFAULT_TAG_BORDER_COLOR);
        bgColor = ta.getColor(R.styleable.SuperTagView_bg_color, SuperTagUtil.DEFAULT_TAG_BG_COLOR);

        borderCheckedColor = ta.getColor(R.styleable.SuperTagView_border_checked_color, 0);
        bgCheckedColor = ta.getColor(R.styleable.SuperTagView_bg_checked_color, 0);

        ta.recycle();

        init();
    }

这里需要注意，不仅要绘制背景色还要绘制边框。还要考虑到选中标签的效果！

所以使用了 StateListDrawable

根据背景色，边框色，选中的颜色来创建StateListDrawable作为背景

private Drawable generateBackgroundDrawable() {
        StateListDrawable stateListDrawable = new StateListDrawable();
        stateListDrawable.addState(CHECK_STATE, new TagBgDrawable(bgCheckedColor, bgRectF, borderCheckedColor, borderRectF, borderWidth, cornerRadius));
        stateListDrawable.addState(new int[]{}, new TagBgDrawable(bgColor, bgRectF, borderColor, borderRectF, borderWidth, cornerRadius));
        return stateListDrawable;
    }

@Override
    protected int[] onCreateDrawableState(int extraSpace) {
        int[] states = super.onCreateDrawableState(extraSpace + CHECK_STATE.length);
        if (isChecked()) {
            mergeDrawableStates(states, CHECK_STATE);
        }
        return states;
    }

    @Override
    public void setChecked(boolean checked) {
        if (this.isChecked != checked) {
            this.isChecked = checked;
            refreshDrawableState();
        }
    }

    @Override
    public boolean isChecked() {
        return isChecked;
    }

    @Override
    public void toggle() {
        setChecked(!isChecked);
    }

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效果图

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• 动态添加删除tag

• 最多选中一个tag

• 最多选中5个tag

• 不限选中个数

• 嵌套ScrollView的使用情况

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引用开源库

compile 'com.jacksen:supertaggroup:1.0' 

gradle 4.0 版本之后，使用下面依赖方式

implementation 'com.jacksen:supertaggroup:1.0'

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源码

https://github.com/crazy1235/SuperTagGroup

欢迎star

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参考

https://github.com/zhuanghongji/FlowLayout

https://github.com/PepernotenX/FlowLayout