Android画板开发之添加文本文字

companion object {
    const val EDIT_MODE_PEN = 0x1L    //画笔模式
    const val EDIT_MODE_ERASER = 0x2L  //橡皮擦模式
    const val EDIT_MODE_TEXT = 0x3L  //文字模式

  }

  @Retention(AnnotationRetention.SOURCE)
  @IntDef(EDIT_MODE_PEN, EDIT_MODE_ERASER, EDIT_MODE_TEXT)
  annotation class EditMode

  /**
   * 设置画笔模式
   */
  fun setModel(@EditMode model: Long) {
    mMode = model
    when (model) {
      EDIT_MODE_PEN -> {
        //画线
        mPaint.xfermode = null
        mPaint.style = Paint.Style.STROKE
      }
      EDIT_MODE_ERASER -> {
        mPaint.xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)

      }
      EDIT_MODE_TEXT -> {
        mPaint.style = Paint.Style.FILL
      }
    }
  }

StaticLayout.Builder builder = StaticLayout.Builder.obtain(mHint, 0,
     mHint.length(), mTextPaint, hintWidth)
     .setAlignment(alignment)
     .setTextDirection(mTextDir)
     .setLineSpacing(mSpacingAdd, mSpacingMult)
     .setIncludePad(mIncludePad)
     .setBreakStrategy(mBreakStrategy)
     .setHyphenationFrequency(mHyphenationFrequency);

public StaticLayout(CharSequence source, //字符串
   TextPaint paint, //画笔对象
   int width,  //layout的宽度，字符串超出宽度时自动换行。
   Layout.Alignment align, //layout的对其方式，有ALIGN_CENTER， ALIGN_NORMAL， ALIGN_OPPOSITE 三种。
   float spacingmult,  //相对行间距，相对字体大小，1.5f表示行间距为1.5倍的字体高度。
   float spacingadd,  //在基础行距上添加多少
   boolean includepad)  //文本顶部和底部是否留白

data class PaintBean(
    var mPaint: Paint,  //保存画笔
    var mPath: Path?,     //保存路径
    var mText: String,    //文本
    var mWidth: Int,
    var mOffX: Float,
    var mOffY: Float,
    private @TPTextView.EditMode var mMode:Long
) {

  constructor(mPaint: Paint, mPath: Path) : this(mPaint,mPath,"",0,0f,0f,TPTextView.EDIT_MODE_PEN)

  /**
   * 撤销和反撤销之后 重新绘制
   * @param canvas 绘制的画布
   */
  fun draw(canvas: Canvas){

    when(mMode){

      TPTextView.EDIT_MODE_TEXT -> {

        if(!TextUtils.isEmpty(mText)){
          //调节画布起始坐标进行绘制
          canvas.translate(mOffX,mOffY)
          //利用staticLayout生成文字，不然不能换行
          val staticLayout = StaticLayout(mText,mPaint as TextPaint,mWidth, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false)
          staticLayout.draw(canvas)
          //Log.e("@@","长度："+staticLayout.width)
          //canvas.drawText(mText,mTextOffX,mTextOffY,mPaint)
          //恢复画布坐标
          canvas.translate(-mOffX,-mOffY)

        }

      }
      else -> {
        canvas.drawPath(mPath,mPaint)
      }

    }

  }

  fun getMode():Long = mMode

}

private var mTextPopup: PopupWindow? = null
private var mTextView: EditText? = null

  /**
   * 显示popup文本输入弹窗
   */
  private fun showTextPopup() {

    if (null == mTextPopup) {
      mTextView = EditText(context)
      mTextView?.hint = "文字"

      mTextPopup = PopupWindow(mTextView,
          WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT,
          true)
      mTextPopup?.setOnDismissListener {
        if (!TextUtils.isEmpty(mTextView?.text)) {
          //添加到列表
          mPaintedList.add(
              PaintBean(TextPaint(mPaint), null, mTextView?.text.toString(), (width - preX).toInt(),preX,preY - mTextView!!.height / 2, EDIT_MODE_TEXT))

          invalidate()
        }
      }
      //让popup显示在软键盘上面
      mTextPopup?.softInputMode = WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE
    }

    mTextView?.requestFocus()

    //自动弹出软键盘，会导致布局变化，重测量、绘制
    val imm = context.getSystemService(Service.INPUT_METHOD_SERVICE) as InputMethodManager
    imm.toggleSoftInput(0, InputMethodManager.HIDE_NOT_ALWAYS)


    mTextPopup?.showAtLocation(this, Gravity.TOP and Gravity.LEFT, preX.toInt(), preY.toInt()+mTextView!!.height)

  }

@SuppressLint("ClickableViewAccessibility")
  override fun onTouchEvent(event: MotionEvent): Boolean {

    when (event.action) {
      MotionEvent.ACTION_DOWN -> { //手指按下的时候
        //记录上次触摸的坐标，注意ACTION_DOWN方法只会执行一次
        preX = event.x
        preY = event.y
        when (mMode) {

          EDIT_MODE_TEXT -> {
            //弹出popupWidnwo输入text
            showTextPopup()
            //文字在隐藏的时候添加到list
          }
          else -> {
            //将起始点移动到当前坐标
            mPath.moveTo(event.x, event.y)
            mPaintedList.add(PaintBean(Paint(mPaint), Path(mPath)))
          }
        }

      }
      MotionEvent.ACTION_MOVE -> { //手指移动的时候
        when (mMode) {
          EDIT_MODE_TEXT -> {

          }
          else -> {
            //绘制圆滑曲线，即贝塞尔曲线,贝塞尔曲线这个知识自行了解
            mPaintedList.get(mPaintedList.size - 1).mPath?.quadTo(preX, preY, event.x, event.y)
            preX = event.x
            preY = event.y
            //重新绘制，会调用onDraw方法
            invalidate()
          }

        }
      }
      MotionEvent.ACTION_UP -> {}
    }

    return true
  }

@SuppressLint("DrawAllocation")
  override fun onDraw(canvas: Canvas) {
    super.onDraw(canvas)

    //超出缓存的就固化到缓存bitmap
    while (mPaintedList.size > PAINT_RECORED_NUM) {
      val paint = mPaintedList.removeAt(0)
      paint.draw(mHoldCanvas!!)
    }

    //绘制固化的内容到缓存Canvas
    mBufferCanvas?.drawBitmap(mHoldBitmap, 0f, 0f, null)

    //绘制记录的画笔
    for (paint in mPaintedList) {
      paint.draw(mBufferCanvas!!)
    }

    //画出缓存bitmap的内容
    canvas.drawBitmap(mBufferBitmap, 0f, 0f, null)

  }