工具类：
class SrcLoopScrollFrameLayout : FrameLayout {
companion object {
/**
* 滚动方向
*/
@IntDef(OUT_SLIDE_TOP, OUT_SLIDE_BOTTOM, OUT_SLIDE_LEFT, OUT_SLIDE_RIGHT)
@Retention(AnnotationRetention.SOURCE)
annotation class ScrollOrientation
/**
* 滚动方向常量
* 0:往上滚出
* 1:往下滚出
* 2:往左滚出
* 3:往右滚出
*/
const val OUT_SLIDE_TOP = 0
const val OUT_SLIDE_BOTTOM = 1
const val OUT_SLIDE_LEFT = 2
const val OUT_SLIDE_RIGHT = 3
/**
* 重绘间隔时间
*/
private const val DEFAULT_DRAW_INTERVALS_TIME = 5L
}
/**
* 间隔时间内平移距离
*/
private var mPanDistance = 0f
/**
* 间隔时间内平移增距
*/
private var mIntervalIncreaseDistance = 0.5f
/**
* 填满当前view所需bitmap个数
*/
private var mBitmapCount = 0
/**
* 是否开始滚动
*/
private var mIsScroll = false
/**
* 滚动方向，默认往上滚出
*/
@ScrollOrientation
private var mScrollOrientation = OUT_SLIDE_TOP
/**
* 遮罩层颜色
*/
@ColorInt
private var mMaskLayerColor = 0
private var mDrawable: Drawable? = null
private var mSrcBitmap: Bitmap? = null
private lateinit var mPaint: Paint
private lateinit var mMatrix: Matrix
constructor(context: Context) : super(context) {
initView(context, null, 0)
}
constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {
initView(context, attrs, 0)
}
constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(
context,
attrs,
defStyleAttr
) {
initView(context, attrs, defStyleAttr)
}
private fun initView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) {
val array = context.theme.obtainStyledAttributes(
attrs,
R.styleable.SrcLoopScrollFrameLayout,
defStyleAttr,
0
)
val speed = array.getInteger(R.styleable.SrcLoopScrollFrameLayout_speed, 3)
mScrollOrientation =
array.getInteger(R.styleable.SrcLoopScrollFrameLayout_scrollOrientation, OUT_SLIDE_TOP)
mIntervalIncreaseDistance *= speed
mDrawable = array.getDrawable(R.styleable.SrcLoopScrollFrameLayout_src)
mIsScroll = array.getBoolean(R.styleable.SrcLoopScrollFrameLayout_isScroll, true)
mMaskLayerColor =
array.getColor(R.styleable.SrcLoopScrollFrameLayout_maskLayerColor, Color.TRANSPARENT)
array.recycle()
setWillNotDraw(false)
mPaint = Paint()
mMatrix = Matrix()
}
override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
super.onSizeChanged(w, h, oldw, oldh)
if (mDrawable == null || mDrawable !is BitmapDrawable) {
return
}
if (visibility == GONE) {
return
}
if (w == 0 || h == 0) {
return
}
if (mSrcBitmap == null) {
val bitmap = (mDrawable as BitmapDrawable).bitmap
//调整色彩模式进行质量压缩
val compressBitmap = bitmap.copy(Bitmap.Config.RGB_565, true)
//缩放 Bitmap
mSrcBitmap = scaleBitmap(compressBitmap)
//计算至少需要几个 bitmap 才能填满当前 view
when (mScrollOrientation) {
OUT_SLIDE_TOP, OUT_SLIDE_BOTTOM -> {
mBitmapCount = measuredHeight / mSrcBitmap!!.height + 1
}
OUT_SLIDE_LEFT, OUT_SLIDE_RIGHT -> {
mBitmapCount = measuredWidth / mSrcBitmap!!.width + 1
}
}
if (!compressBitmap.isRecycled) {
compressBitmap.isRecycled
System.gc()
}
}
}
override fun onDraw(canvas: Canvas) {
super.onDraw(canvas)
if (mSrcBitmap == null) {
return
}
val length = if (scrollOrientationIsVertical()) mSrcBitmap!!.height else mSrcBitmap!!.width
if (length + mPanDistance != 0f) {
//第一张图片未完全滚出屏幕
mMatrix.reset()
when (mScrollOrientation) {
OUT_SLIDE_TOP -> {
mMatrix.postTranslate(0f, mPanDistance)
}
OUT_SLIDE_BOTTOM -> {
mMatrix.postTranslate(0f, measuredHeight - length - mPanDistance)
}
OUT_SLIDE_LEFT -> {
mMatrix.postTranslate(mPanDistance, 0f)
}
OUT_SLIDE_RIGHT -> {
mMatrix.postTranslate(measuredWidth - length - mPanDistance, 0f)
}
}
canvas.drawBitmap(mSrcBitmap!!, mMatrix, mPaint)
}
if (length + mPanDistance < (if (scrollOrientationIsVertical()) measuredHeight else measuredWidth)) {
//用于补充留白的图片出现在屏幕
for (i in 0 until mBitmapCount) {
mMatrix.reset()
when (mScrollOrientation) {
OUT_SLIDE_TOP -> {
mMatrix.postTranslate(0f, (i + 1) * length + mPanDistance)
}
OUT_SLIDE_BOTTOM -> {
mMatrix.postTranslate(0f, measuredHeight - (i + 2) * length - mPanDistance)
}
OUT_SLIDE_LEFT -> {
mMatrix.postTranslate((i + 1) * length + mPanDistance, 0f)
}
OUT_SLIDE_RIGHT -> {
mMatrix.postTranslate(measuredWidth - (i + 2) * length - mPanDistance, 0f)
}
}
canvas.drawBitmap(mSrcBitmap!!, mMatrix, mPaint)
}
}
//绘制遮罩层
if (mMaskLayerColor != Color.TRANSPARENT) {
canvas.drawColor(mMaskLayerColor)
}
//延时重绘实现滚动效果
if (mIsScroll) {
handler.postDelayed(mRedrawRunnable, DEFAULT_DRAW_INTERVALS_TIME)
}
}
/**
* 重绘
*/
private val mRedrawRunnable = Runnable {
val length = if (scrollOrientationIsVertical()) mSrcBitmap!!.height else mSrcBitmap!!.width
if (length + mPanDistance <= 0) {
//第一张已完全滚出屏幕，重置平移距离
mPanDistance = 0f
}
mPanDistance -= mIntervalIncreaseDistance
invalidate()
}
/**
* 设置背景图 bitmap
* 通过该方法设置的背景图，当 屏幕翻转/暗黑模式切换 等涉及到 activity 重构的情况出现时，需要在 activity 重构后重新设置背景图
* @srcBitmap 背景图
* @isMassReduce 是否进行质量压缩(通过调整色彩模式实现，默认进行压缩)
*/
fun setSrcBitmap(srcBitmap: Bitmap, isMassReduce: Boolean = true) {
val oldScrollStatus = mIsScroll
if (oldScrollStatus) {
stopScroll()
}
val compressBitmap: Bitmap =
if (isMassReduce && srcBitmap.config != Bitmap.Config.RGB_565) {
//调整色彩模式进行质量压缩
srcBitmap.copy(Bitmap.Config.RGB_565, true)
} else {
srcBitmap
}
//按当前View宽度比例缩放 Bitmap
mSrcBitmap = scaleBitmap(compressBitmap)
//计算至少需要几个 bitmap 才能填满当前 view
mBitmapCount =
if (scrollOrientationIsVertical()) measuredHeight / mSrcBitmap!!.height + 1 else measuredWidth / mSrcBitmap!!.width + 1
if (!srcBitmap.isRecycled) {
srcBitmap.isRecycled
System.gc()
}
if (!compressBitmap.isRecycled) {
compressBitmap.isRecycled
System.gc()
}
if (oldScrollStatus) {
startScroll()
}
}
/**
* 开始滚动
*/
fun startScroll() {
if (mSrcBitmap != null && mIsScroll) {
return
}
mIsScroll = true
handler.postDelayed(mRedrawRunnable, DEFAULT_DRAW_INTERVALS_TIME)
}
/**
* 停止滚动
*/
fun stopScroll() {
if (!mIsScroll) {
return
}
mIsScroll = false
handler.removeCallbacks(mRedrawRunnable)
}
/**
* 设置滚动方向
*/
fun setScrollOrientation(@ScrollOrientation scrollOrientation: Int) {
mPanDistance = 0f
mScrollOrientation = scrollOrientation
if (mSrcBitmap != null) {
if (mDrawable != null && mDrawable is BitmapDrawable) {
val bitmap = (mDrawable as BitmapDrawable).bitmap
if (!bitmap.isRecycled) {
setSrcBitmap(bitmap)
return
}
}
setSrcBitmap(mSrcBitmap!!)
}
}
/**
* 切换滚动方向
*/
fun changeScrollOrientation() {
mPanDistance = 0f
if (mScrollOrientation == OUT_SLIDE_RIGHT) {
mScrollOrientation = OUT_SLIDE_TOP
} else {
mScrollOrientation++
}
if (mSrcBitmap != null) {
if (mDrawable != null && mDrawable is BitmapDrawable) {
val bitmap = (mDrawable as BitmapDrawable).bitmap
if (!bitmap.isRecycled) {
setSrcBitmap(bitmap)
return
}
}
setSrcBitmap(mSrcBitmap!!)
}
}
/**
* 判断是否为竖直滚动
*/
private fun scrollOrientationIsVertical(): Boolean {
return mScrollOrientation == OUT_SLIDE_TOP || mScrollOrientation == OUT_SLIDE_BOTTOM
}
/**
* 缩放 Bitmap
*/
private fun scaleBitmap(originBitmap: Bitmap): Bitmap? {
val width = originBitmap.width
val height = originBitmap.height
val newHeight: Int
val newWidth: Int
if (scrollOrientationIsVertical()) {
newWidth = measuredWidth
newHeight = newWidth * height / width
} else {
newHeight = measuredHeight
newWidth = newHeight * width / height
}
return Bitmap.createScaledBitmap(originBitmap, newWidth, newHeight, true)
}
}styles.xml
<declare-styleable name="SrcLoopScrollFrameLayout">
<attr name="src" />
<attr name="maskLayerColor" />
<attr name="isScroll" />
<attr name="speed" />
<attr name="scrollOrientation" />
</declare-styleable>使用：
<SrcLoopScrollFrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white"
app:layout_constraintTop_toTopOf="parent"
app:scrollOrientation="toTop"
app:src="@drawable/img_gui_bg">
//正常布局代码块
</SrcLoopScrollFrameLayout>