Android APP 自定义水印(kotlin)

自定义WaterMarkView

/** * Created by guc on 2020/6/12. * Description：水印 */class WaterMarkView(context: Context, attrs: AttributeSet?, defStyle: Int) :    View(context, attrs, defStyle) {    constructor(context: Context, attrs: AttributeSet) : this(context, attrs, 0)    constructor(context: Context) : this(context, null, 0)    companion object {        const val TAG = "WaterMarkView"        const val DEFAULT_RADIAN: Float = (PI / 6).toFloat()    }    var markText: CharSequence = "水印"    private val path = Path()    private var lineHeight = 0  //px    private var markerTextSize = 0f    private var singleMarkerWidth = 0    private var singleMarkerHeight = 0    private var markerSpace = 0//间距    private var deltaFixSpace = 0//修正间距    var radian = DEFAULT_RADIAN//弧度    private var repeatCountX = 1    private var repeatCountY = 1    private var repeatSpace = 1    private val paint = Paint().apply {        isAntiAlias = true        color = Color.DKGRAY        style = Paint.Style.FILL    }    init {        val a = context.obtainStyledAttributes(attrs, R.styleable.WaterMarkView)        markText = a.getString(R.styleable.WaterMarkView_markerText) ?: "水印"        LogG.loge(TAG, "获取前：$lineHeight")        lineHeight = a.getDimensionPixelOffset(            R.styleable.WaterMarkView_lineHeight,            dp2px(50f)        )        LogG.loge(TAG, "获取后：$lineHeight")        markerTextSize = a.getDimension(R.styleable.WaterMarkView_markerTextSize, 48f)        markerSpace =            a.getDimension(R.styleable.WaterMarkView_markerSpace, dp2px(30f).toFloat()).toInt()        deltaFixSpace =            a.getDimension(R.styleable.WaterMarkView_fixSpace, markerSpace.toFloat() / 2).toInt()        radian = a.getFloat(R.styleable.WaterMarkView_radian, DEFAULT_RADIAN)        a.recycle()    }    @SuppressLint("DrawAllocation")    override fun onDraw(canvas: Canvas) {        super.onDraw(canvas)        val rectText = Rect()        paint.textSize = markerTextSize        paint.getTextBounds(markText.toString(), 0, markText.toString().length, rectText)        singleMarkerWidth = rectText.width()        singleMarkerHeight = rectText.height()        val space = "a"        paint.getTextBounds(space, 0, space.length, rectText)        repeatSpace = markerSpace / rectText.width()        repeatCountX = ceil(width * 1.0 / cos(radian) / (singleMarkerWidth + markerSpace)).toInt()        repeatCountY = floor(height * 1.0 / lineHeight).toInt()        val itemStdHeight = getItemHeight()        for (i in 1..repeatCountY) {            path.reset()            path.moveTo(0f + deltaFixSpace, i * lineHeight.toFloat())            val x = getEndX(itemStdHeight, i) + deltaFixSpace            val y = getEndY(itemStdHeight, i)            path.lineTo(x, y)            canvas.drawTextOnPath(getLineText(), path, 0f, 0f, paint)        }    }    private fun isEnoughHeight(itemHeight: Float, times: Int) = itemHeight <= times * lineHeight    private fun getEndX(itemHeight: Float, times: Int): Float =        if (isEnoughHeight(                itemHeight,                times            )        ) width.toFloat() else (lineHeight * times * 1.0f / tan(            radian        ))    private fun getEndY(itemHeight: Float, times: Int): Float =        if (isEnoughHeight(itemHeight, times)) (lineHeight * times - itemHeight) else 0f    private fun getItemHeight(): Float {        return width * tan(radian)    }    private fun getLineText(): String {        val sb = StringBuilder()        repeat(repeatCountX) {            sb.append(markText)            repeat(repeatSpace) {                sb.append(" ")            }        }        return sb.toString()    }    private fun dp2px(dipValue: Float): Int {        val scale = resources.displayMetrics.density        return (dipValue * scale + 0.5f).toInt()    }}

自定义属性

创建水印布局layout_water_mark.xml

<?xml version="1.0" encoding="utf-8"?>

调用Api

object WaterMarkUtil{    private const val VIEW_TAG = "view_tag"    var enable = false    var text = "水印"    //在Activity的onActivityStart()方法调用    fun onActivityStart(activity:Activity){         val rootView = activity.window.decorView.findViewById(android.R.id.content)        if (enable && text.isNotEmpty() && rootView.findViewWithTag(VIEW_TAG) == null) {            val waterMarkView =                LayoutInflater.from(activity)                    .inflate(R.layout.layout_water_mark, null) as WaterMarkView            waterMarkView.tag = VIEW_TAG            waterMarkView.markText = text            rootView.addView(waterMarkView)        }            }}

水印设置及调用

//开启水印，并设置水印文本override fun onCreate(savedInstanceState: Bundle?) {    super.onCreate(savedInstanceState)    WaterMarkUtil.enable = true    WaterMarkUtil.text = "自定义水印"}//添加水印override fun onStart() {    super.onStart()    WaterMarkUtil.onActivityStart(this)}

效果

Android APP 自定义水印(kotlin)_第1张图片

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