自定义TabLayout

96
momentslz
2018.02.23 17:24* 字数 176

本文为kotlin仿开眼视频Android客户端的后续补充内容,本篇为大家介绍如何对TabLayout进行定制使用,基于项目需求,本篇主要对部分功能进行了定制,如:指示器距离文字的距离、文字选中加粗、文字选中变大等

本文部分代码参考:FlycoTabLayout

效果图

tab_1.png

效果-1

tab_2.png

效果-2

参数详解

属性源码

<declare-styleable name="MyTabLayout">
        <attr name="textNormalSize" format="dimension" />
        <attr name="textSelectSize" format="dimension" />
        <attr name="textNormalColor" format="color" />
        <attr name="textSelectColor" format="color" />
        <attr name="underLineHeight" format="dimension" />
        <attr name="underlineColor" format="color" />
        <attr name="indicatorHeight" format="dimension" />
        <attr name="indicatorWidth" format="dimension" />
        <attr name="indicatorSpacing" format="dimension" />
        <attr name="isTextBold" format="boolean" />
        <attr name="tabPadding" format="dimension" />
        <attr name="indicatorColor" format="color" />
        <attr name="tabSpaceEqual" format="boolean" />
    </declare-styleable>

属性参数详解

参数 用处
textNormalSize tab未被选中时字体大小
textSelectSize tab被选中时字体大小
textNormalColor tab未被选中时字体颜色
textSelectColor tab被选中时字体颜色
underLineHeight tablayout下面整个一条的线的高度
underlineColor tablayout下面整个一条的线的颜色
indicatorHeight 文字下方指示器的高度
indicatorWidth 文字下方指示器的宽度
indicatorSpacing 文字下方指示器距离上面文字的间距
indicatorColor 文字下方指示器的颜色
isTextBold 文字选中时是否加粗
tabPadding 文字左右间的间隙大小
tabSpaceEqual tab中的文字是否等分tablayout的宽度,参考效果-2

与viewpager合并使用

var mAdapter = MyPagerAdapter(fragmentManager)
viewpager.adapter = mAdapter
//tab列表
val stringArray = mTitle.toArray(arrayOfNulls<String>(0))
tab_layout.setViewPager(viewpager, stringArray as Array<String>)
viewpager.offscreenPageLimit = 3
viewpager.currentItem = 0
viewpager.addOnPageChangeListener(this)

源码

使用参考详见:https://github.com/momentslz/Eyepetizer

源码文件下载地址:
https://github.com/momentslz/Eyepetizer/blob/master/app/src/main/java/com/moment/eyepetizer/view/TabLayout.kt

或如代码如下:

/**
 * Created by moment on 2018/2/22.
 * FlycoTabLayout 仿写,并提取部分功能原地址链接:
 * https://github.com/H07000223/FlycoTabLayout
 */
open class TabLayout(context: Context, attrs: AttributeSet) : HorizontalScrollView(context, attrs), ViewPager.OnPageChangeListener {
    private var mContext: Context? = null
    private var textNormalSize: Float = 0.toFloat()
    private var textSelectSize: Float = 0.toFloat()
    private var textNormalColor: Int = 0
    private var textSelectColor: Int = 0
    private var underlineHeight: Float = 0.toFloat()
    private var underlineColor: Int = 0
    private var indicatorHeight: Float = 0.toFloat()
    private var indicatorWidth: Float = 0.toFloat()
    private var indicatorSpacing: Float = 0.toFloat()
    private var isTextBold: Boolean = false
    private var tabPadding: Float = 0.toFloat()
    private var indicatorColor: Int = 0
    private var tabSpaceEqual: Boolean = false


    private var selectListener: OnTagSelectListener? = null
    private var mTabsContainer: LinearLayout? = null
    private var mCurrentTab = 0
    private var mViewPager: ViewPager? = null
    var tabCount: Int = 0
        private set
    private var mTitles: ArrayList<String>? = null

    private val mRectPaint = Paint(Paint.ANTI_ALIAS_FLAG)

    private val mIndicatorDrawable = GradientDrawable()
    /**
     * indicator
     */

    private val mIndicatorMarginLeft = 0f
    private val mIndicatorMarginTop = 0f
    private val mIndicatorMarginRight = 0f
    /**
     * 用于绘制显示器
     */
    private val mIndicatorRect = Rect()

    private var mCurrentPositionOffset: Float = 0.toFloat()

    /**
     * 用于实现滚动居中
     */
    private val mTabRect = Rect()
    private var mLastScrollX: Int = 0

    init {
        initResource(context, attrs)
    }


    private fun initResource(context: Context, attrs: AttributeSet) {
        mContext = context
        val typedArray = context.obtainStyledAttributes(attrs, R.styleable.MyTabLayout)
        textNormalSize = typedArray.getDimension(R.styleable.MyTabLayout_textNormalSize, sp2px(context, 14f).toFloat())
        textSelectSize = typedArray.getDimension(R.styleable.MyTabLayout_textSelectSize, textNormalSize)
        textNormalColor = typedArray.getColor(R.styleable.MyTabLayout_textNormalColor, Color.GRAY)
        textSelectColor = typedArray.getColor(R.styleable.MyTabLayout_textSelectColor, Color.BLACK)
        underlineHeight = typedArray.getDimension(R.styleable.MyTabLayout_underLineHeight, dp2px(context, 0.5f).toFloat())
        indicatorWidth = typedArray.getDimension(R.styleable.MyTabLayout_indicatorWidth, -1f)
        indicatorHeight = typedArray.getDimension(R.styleable.MyTabLayout_indicatorHeight, dp2px(context, 3f).toFloat())
        indicatorSpacing = typedArray.getDimension(R.styleable.MyTabLayout_indicatorSpacing, dp2px(context, 6f).toFloat())
        isTextBold = typedArray.getBoolean(R.styleable.MyTabLayout_isTextBold, true)
        underlineColor = typedArray.getColor(R.styleable.MyTabLayout_underlineColor, Color.parseColor("#EEEEEE"))
        indicatorColor = typedArray.getColor(R.styleable.MyTabLayout_indicatorColor, Color.BLACK)
        tabSpaceEqual = typedArray.getBoolean(R.styleable.MyTabLayout_tabSpaceEqual, false)
        tabPadding = typedArray.getDimension(R.styleable.MyTabLayout_tabPadding, (if (tabSpaceEqual) dp2px(context, 5f) else dp2px(context, 20f)).toFloat())
        typedArray.recycle()

        mRectPaint.color = underlineColor
        mIndicatorDrawable.setColor(indicatorColor)
        mTabsContainer = LinearLayout(context)
        val lp = ViewGroup.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT)
        mTabsContainer!!.layoutParams = lp
        mTabsContainer!!.gravity = Gravity.CENTER_VERTICAL
        isFillViewport = true
        setWillNotDraw(false)
        isVerticalScrollBarEnabled = false
        isHorizontalScrollBarEnabled = false
        addView(mTabsContainer)

    }

    //setter and getter
    fun setCurrentTab(currentTab: Int) {
        this.mCurrentTab = currentTab
        mViewPager!!.currentItem = currentTab

    }

    fun setCurrentTab(currentTab: Int, smoothScroll: Boolean) {
        this.mCurrentTab = currentTab
        mViewPager!!.setCurrentItem(currentTab, smoothScroll)
    }

    fun addTab(position: Int, title: String?, textView: TextView?) {
        if (textView != null) {
            if (title != null) {
                textView.gravity = Gravity.CENTER
                textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, textNormalSize)
                textView.setTextColor(textNormalColor)
                textView.text = title
                textView.setOnClickListener { v ->
                    val position = mTabsContainer!!.indexOfChild(v)
                    if (position != -1) {
                        if (mViewPager!!.currentItem != position) {
                            mViewPager!!.currentItem = position
                        } else {
                            if (selectListener != null) {
                                selectListener!!.onTagSelected(position, if (mTitles != null) mTitles!![position] else mViewPager!!.adapter.getPageTitle(position).toString())
                            }
                        }
                    }
                }
            }
        }
        val lp = if (tabSpaceEqual)
            LinearLayout.LayoutParams(0, ViewGroup.LayoutParams.MATCH_PARENT, 1.0f)
        else
            LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.MATCH_PARENT)
        lp.gravity = Gravity.CENTER
        mTabsContainer!!.addView(textView, position, lp)

    }

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        val height = height
        val paddingLeft = paddingLeft
        var top = 0
        var bottom = height

        if (mTabsContainer != null && mTabsContainer!!.getChildAt(mCurrentTab) != null) {
            top = mTabsContainer!!.getChildAt(mCurrentTab).top
            bottom = mTabsContainer!!.getChildAt(mCurrentTab).bottom
        }

        val tabHeight = top + bottom

        canvas.drawRect(paddingLeft.toFloat(), height - underlineHeight, (mTabsContainer!!.width + paddingLeft).toFloat(), height.toFloat(), mRectPaint)

        calcIndicatorRect()

        if (indicatorHeight > 0 && indicatorWidth > 0) {
            mIndicatorDrawable.setBounds(paddingLeft + mIndicatorMarginLeft.toInt() + mIndicatorRect.left,
                    tabHeight - tabPadding.toInt() * 2 + indicatorSpacing.toInt(),
                    paddingLeft + mIndicatorRect.right - mIndicatorMarginRight.toInt(),
                    tabHeight - tabPadding.toInt() * 2 + indicatorSpacing.toInt() + indicatorHeight.toInt())

            mIndicatorDrawable.draw(canvas)
        } else {
            mIndicatorDrawable.setBounds(paddingLeft + mIndicatorMarginLeft.toInt() + mIndicatorRect.left,
                    height - indicatorHeight.toInt(),
                    paddingLeft + mIndicatorRect.right - mIndicatorMarginRight.toInt(),
                    height)
            mIndicatorDrawable.draw(canvas)
        }
    }

    private fun calcIndicatorRect() {
        val currentTabView = mTabsContainer!!.getChildAt(this.mCurrentTab) ?: return
        var left = currentTabView.left.toFloat()
        var right = currentTabView.right.toFloat()

        if (this.mCurrentTab < tabCount - 1) {
            val nextTabView = mTabsContainer!!.getChildAt(this.mCurrentTab + 1)
            val nextTabLeft = nextTabView.left.toFloat()
            val nextTabRight = nextTabView.right.toFloat()

            left += mCurrentPositionOffset * (nextTabLeft - left)
            right += mCurrentPositionOffset * (nextTabRight - right)
        }

        mIndicatorRect.left = left.toInt()
        mIndicatorRect.right = right.toInt()

        mTabRect.left = left.toInt()
        mTabRect.right = right.toInt()

        if (indicatorWidth >= 0) {
            //indicatorWidth大于0时,圆角矩形以及三角形
            var indicatorLeft = currentTabView.left + (currentTabView.width - indicatorWidth) / 2

            if (this.mCurrentTab < tabCount - 1) {
                val nextTab = mTabsContainer!!.getChildAt(this.mCurrentTab + 1)
                indicatorLeft += mCurrentPositionOffset * (currentTabView.width / 2 + nextTab.width / 2)
            }

            mIndicatorRect.left = indicatorLeft.toInt()
            mIndicatorRect.right = (mIndicatorRect.left + indicatorWidth).toInt()
        }
    }

    /**
     * 关联ViewPager,用于不想在ViewPager适配器中设置titles数据的情况
     */
    fun setViewPager(vp: ViewPager?, titles: Array<String>) {
        if (vp == null || vp.adapter == null) {
            throw IllegalStateException("ViewPager or ViewPager adapter can not be NULL !")
        }

        if (titles == null || titles.size == 0) {
            throw IllegalStateException("Titles can not be EMPTY !")
        }

        if (titles.size != vp.adapter.count) {
            throw IllegalStateException("Titles length must be the same as the page count !")
        }

        this.mViewPager = vp
        mTitles = ArrayList()
        Collections.addAll(mTitles!!, *titles)

        this.mViewPager!!.removeOnPageChangeListener(this)
        this.mViewPager!!.addOnPageChangeListener(this)
        notifyDataSetChanged()
    }

    /**
     * 关联ViewPager,用于连适配器都不想自己实例化的情况
     */
    fun setViewPager(vp: ViewPager?, titles: Array<String>?, fa: FragmentActivity, fragments: ArrayList<Fragment>) {
        if (vp == null) {
            throw IllegalStateException("ViewPager can not be NULL !")
        }

        if (titles == null || titles.isEmpty()) {
            throw IllegalStateException("Titles can not be EMPTY !")
        }

        this.mViewPager = vp
        this.mViewPager!!.adapter = InnerPagerAdapter(fa.supportFragmentManager, fragments, titles)

        this.mViewPager!!.removeOnPageChangeListener(this)
        this.mViewPager!!.addOnPageChangeListener(this)
        notifyDataSetChanged()
    }

    /**
     * 更新数据
     */
    private fun notifyDataSetChanged() {
        mTabsContainer!!.removeAllViews()
        this.tabCount = if (mTitles == null) mViewPager!!.adapter.count else mTitles!!.size
        var tabView: TextView
        for (i in 0 until tabCount) {
            tabView = TextView(mContext)
            val pageTitle = if (mTitles == null) mViewPager!!.adapter.getPageTitle(i) else mTitles!![i]
            addTab(i, pageTitle.toString(), tabView)
        }

        updateTabStyles()
    }

    private fun updateTabStyles() {
        for (i in 0 until tabCount) {
            val v = mTabsContainer!!.getChildAt(i)
            val tv_tab_title = v as TextView
            if (tv_tab_title != null) {
                tv_tab_title.setTextColor(if (i == mCurrentTab) textSelectColor else textNormalColor)
                tv_tab_title.setTextSize(TypedValue.COMPLEX_UNIT_PX, if (i == mCurrentTab) textSelectSize else textNormalSize)
                tv_tab_title.setPadding(tabPadding.toInt(), tabPadding.toInt(), tabPadding.toInt(), tabPadding.toInt())
                if (isTextBold) {
                    tv_tab_title.paint.isFakeBoldText = i == mCurrentTab
                }

            }
        }
    }

    override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {
        this.mCurrentTab = position
        this.mCurrentPositionOffset = positionOffset
        scrollToCurrentTab()
        invalidate()
    }

    /**
     * HorizontalScrollView滚到当前tab,并且居中显示
     */
    private fun scrollToCurrentTab() {
        if (tabCount <= 0) {
            return
        }

        val offset = (mCurrentPositionOffset * mTabsContainer!!.getChildAt(mCurrentTab).width).toInt()
        /**当前Tab的left+当前Tab的Width乘以positionOffset */
        var newScrollX = mTabsContainer!!.getChildAt(mCurrentTab).left + offset

        if (mCurrentTab > 0 || offset > 0) {
            /**HorizontalScrollView移动到当前tab,并居中 */
            newScrollX -= width / 2 - paddingLeft
            calcIndicatorRect()
            newScrollX += (mTabRect.right - mTabRect.left) / 2
        }

        if (newScrollX != mLastScrollX) {
            mLastScrollX = newScrollX
            /** scrollTo(int x,int y):x,y代表的不是坐标点,而是偏移量
             * x:表示离起始位置的x水平方向的偏移量
             * y:表示离起始位置的y垂直方向的偏移量
             */
            scrollTo(newScrollX, 0)
        }
    }

    override fun onSaveInstanceState(): Parcelable {
        val bundle = Bundle()
        bundle.putParcelable("instanceState", super.onSaveInstanceState())
        bundle.putInt("mCurrentTab", mCurrentTab)
        return bundle
    }

    override fun onRestoreInstanceState(state: Parcelable?) {
        var state = state
        if (state is Bundle) {
            val bundle = state as Bundle?
            mCurrentTab = bundle!!.getInt("mCurrentTab")
            state = bundle.getParcelable("instanceState")
            if (mCurrentTab != 0 && mTabsContainer!!.childCount > 0) {
                updateTabSelection(mCurrentTab)
                scrollToCurrentTab()
            }
        }
        super.onRestoreInstanceState(state)
    }

    private fun updateTabSelection(position: Int) {
        for (i in 0 until tabCount) {
            val tabView = mTabsContainer!!.getChildAt(i)
            val isSelect = i == position
            val tab_title = tabView as TextView

            if (tab_title != null) {
                tab_title.setTextColor(if (isSelect) textSelectColor else textNormalColor)
                tab_title.setTextSize(TypedValue.COMPLEX_UNIT_PX, if (isSelect) textSelectSize else textNormalSize)
                if (isTextBold) {
                    tab_title.paint.isFakeBoldText = isSelect
                }
            }
        }
    }

    override fun onPageSelected(position: Int) = updateTabSelection(position)

    override fun onPageScrollStateChanged(state: Int) = Unit

    internal inner class InnerPagerAdapter(fm: FragmentManager, fragments: ArrayList<Fragment>, private val titles: Array<String>) : FragmentPagerAdapter(fm) {
        private var fragments = ArrayList<Fragment>()

        init {
            this.fragments = fragments
        }

        override fun getCount(): Int = fragments.size

        override fun getPageTitle(position: Int): CharSequence = titles[position]

        override fun getItem(position: Int): Fragment = fragments[position]

        override fun destroyItem(container: ViewGroup?, position: Int, `object`: Any) =// 覆写destroyItem并且空实现,这样每个Fragment中的视图就不会被销毁
                // super.destroyItem(container, position, object);
                Unit

        override fun getItemPosition(`object`: Any?): Int = PagerAdapter.POSITION_NONE
    }

    interface OnTagSelectListener {
        fun onTagSelected(position: Int, tag: String)
    }

    fun addOnTagSelectListener(listener: OnTagSelectListener) {
        selectListener = listener
    }

    private fun dp2px(context: Context, dp: Float): Int {
        val scale = context.resources.displayMetrics.density
        return (dp * scale + 0.5f).toInt()
    }

    private fun sp2px(context: Context, sp: Float): Int {
        val scale = context.resources.displayMetrics.scaledDensity
        return (sp * scale + 0.5f).toInt()
    }
}
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