手把手教你写酷炫Android自定义view
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内容图文
1、先看效果 如果你对 以下内容不感兴趣 直接下载demo
简单的用法：
allprojects {
repositories {
...
maven { url 'https://jitpack.io' }
}
}dependencies {
implementation 'com.github.zhoulinxue:animatedTabView:1.0.2'
}package org.zhx.commom.widgets.animatedtabview.demo
import android.app.ActionBar
import android.graphics.Color
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import kotlinx.android.synthetic.main.activity_main.*
import org.zhx.commom.widgets.AnimatedTabView
import kotlin.random.Random
class MainActivity : AppCompatActivity(), AnimatedTabView.OnItemChangeLisenter {
private val images = arrayOf(
R.drawable.ic_home_white_36dp,
R.drawable.ic_visibility_white_36dp,
R.drawable.ic_shopping_cart_white_36dp,
R.drawable.ic_perm_identity_white_36dp
)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var builder = AnimatedTabView.Builder(this)
builder.height = 120
builder.arrays = resources.getStringArray(R.array.tab_item_array)
builder.images = images
builder.selectedTextColor = Color.GREEN // default Color.WHITE
builder.unSelectedTextColor = Color.WHITE // default Color.WHITE
builder.backgroundColor =
resources.getColor(R.color.black_30) // default #30000000 不设置 就不绘制 背景
builder.setOnItemClick(this)
var view: AnimatedTabView = builder.build()
test_table_container.addView(view)
tab_btn.setOnClickListener {
var position = Random.nextInt(images.size + 1) - 1
view.setSelection(position)
bottom_tabView.setSelection(position)
}
var builder2 = AnimatedTabView.Builder(this)
builder2.height = 120
builder2.arrays = resources.getStringArray(R.array.tab_item_array)
builder2.images = images
builder2.selectedTextColor = Color.GREEN // default Color.WHITE
builder2.unSelectedTextColor = Color.WHITE // default Color.WHITE
// builder2.backgroundColor =resources.getColor(R.color.black_30) // default #30000000 不设置 就不绘制 背景
builder2.setOnItemClick(this)
bottom_tabView.setBuilder(builder2)
}
override fun onItemSelected(position: Int) {
Log.e("AnimatedTabView", "itemclick $position")
}
}2、自定义一个动画效果 这里我们使用 Android 系统类：ValueAnimator
var valueAnimator = ValueAnimator()
valueAnimator.setFloatValues(0f, totalValus.toFloat())
valueAnimator.duration = ANIMATION_DURATION
valueAnimator.start()
valueAnimator.addUpdateListener(this)
valueAnimator.addListener(object : AnimatorListenerAdapter() {
override fun onAnimationEnd(animation: Animator) {
//TODO 重置状态参数
}
override fun onAnimationStart(animation: Animator) {
//TODO 保存状态参数
}
})
3、监听动画切换状态 核心代码片段
override fun onAnimationUpdate(animation: ValueAnimator) {
mProcessValus = animation.animatedValue as Float
if (mProcessValus != 0f) {
mProcess = mProcessValus / (targetX - currentX)
currentAlpha = (255 * mProcess).toInt();
invalidate()
}
}4、全部代码
package org.zhx.commom.widgets
import android.animation.Animator
import android.animation.AnimatorListenerAdapter
import android.animation.ValueAnimator
import android.content.Context
import android.graphics.*
import android.util.AttributeSet
import android.util.Log
import android.util.SparseArray
import android.view.GestureDetector
import android.view.MotionEvent
import android.view.View
import java.util.*
class AnimatedTabView : View, ValueAnimator.AnimatorUpdateListener {
constructor(context: Context) : super(context)
constructor(context: Context, attributeSet: AttributeSet) : super(context, attributeSet)
constructor(context: Context, attributeSet: AttributeSet, arg: Int) : super(
context,
attributeSet,
arg
)
/**
* bitmap paint
*/
private val mBitmapPaint: Paint by lazy {
Paint().also {
it.color = Color.WHITE
it.style = Paint.Style.FILL
}
}
/**
* cicle paint
*/
private val mCiclePaint: Paint by lazy {
Paint().also {
it.color = resources.getColor(R.color.white)
it.style = Paint.Style.STROKE
}
}
private val mTextPaint: Paint by lazy {
var paint = Paint()
paint.color = Color.WHITE
paint.style = Paint.Style.FILL
paint.textSize = 30f
paint
}
private val mBackgroundPaint: Paint by lazy {
var paint = Paint()
paint.color = resources.getColor(R.color.black_30)
paint.style = Paint.Style.FILL
paint
}
private val TAG = AnimatedTabView::class.java.simpleName
//item count
private var itemCount = 0
// radius
private var mRadius = 0
// item height
private var mHeight = mRadius * 2
// item height
private var mItemHeight = mRadius * 2
//view width
private var mWidth = mItemHeight * itemCount
//view width
private var mItemWidth = mItemHeight * itemCount
//background Rect
private var mCicleRectF: RectF? = null
// animation process
private var mProcess = 1f
// translation valus
private var mProcessValus = 0f
private var currentX = mRadius
private var targetX = 0
private var currentPosition = 1
private var mLastPosition = currentPosition
private val MAX_ALPHA = 255
private var currentAlpha = MAX_ALPHA
private val valueAnimator: ValueAnimator by lazy {
var valueAnimator = ValueAnimator()
valueAnimator?.addUpdateListener(this)
valueAnimator?.addListener(object : AnimatorListenerAdapter() {
override fun onAnimationEnd(animation: Animator) {
mProcess = 1f
mProcessValus = 0f
currentX = targetX
}
override fun onAnimationStart(animation: Animator) {
mLastPosition = currentPosition
currentPosition = getCurrentPositionByX(targetX)
Log.e(TAG, "$mLastPosition current : $currentPosition")
if (mLastPosition != currentPosition) {
mBuilder?.onItemClick?.onItemSelected(currentPosition - 1)
}
}
})
valueAnimator
}
private val textRect = Rect()
private val ANIMATION_DURATION: Long = 400
private var mBuilder: Builder? = null
private val sparseArray = SparseArray<Bitmap>()
private fun getTargetX(x: Float): Int {
return (x / mItemWidth).toInt() * mItemWidth + mItemWidth / 2
}
private fun isMoving(): Boolean {
return valueAnimator != null && valueAnimator?.isRunning!!
}
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
mWidth = WidgetUtil.measureWidth(widthMeasureSpec, mWidth)
mHeight = WidgetUtil.measureHeight(heightMeasureSpec, mHeight)
setMeasuredDimension(mWidth, mHeight)
mCicleRectF = RectF(0f, 0f, mWidth.toFloat(), mHeight.toFloat())
currentX = getXByPosition(currentPosition, 0).toInt()
mItemWidth = mWidth / itemCount
}
override fun onDraw(canvas: Canvas) {
super.onDraw(canvas)
if (itemCount == 0) {
return
}
drawbackGround(canvas)
drawSelctedTag(canvas)
for (i in 1 until itemCount + 1) {
val bitmap = sparseArray[i]
val text = mBuilder?.arrays!![i - 1]
mTextPaint?.getTextBounds(text, 0, text.length, textRect)
if (currentPosition != i && mLastPosition != i) {
mBitmapPaint.alpha = MAX_ALPHA
canvas.drawBitmap(
bitmap, getXByPosition(i, bitmap.width / 2),
(mHeight / 2 - bitmap.height / 2).toFloat(),
mBitmapPaint
)
} else if (currentPosition != i && mLastPosition == i) {
if (mBuilder?.unSelectedTextColor != 0) {
mTextPaint.color = mBuilder?.unSelectedTextColor!!
} else {
mTextPaint.color = Color.WHITE
}
mTextPaint.alpha = MAX_ALPHA - currentAlpha
canvas.drawText(
text,
getXByPosition(i, textRect.width() / 2),
(mHeight / 2 + textRect.height() / 2) * (1 - mProcess), mTextPaint
)
mBitmapPaint.alpha = currentAlpha
canvas.drawBitmap(
bitmap,
getXByPosition(i, bitmap.width / 2),
mHeight / 2 - bitmap.height / 2 + bitmap.height * (1 - mProcess),
mBitmapPaint
)
} else if (currentPosition == i) {
if (mBuilder?.selectedTextColor != 0) {
mTextPaint.color = mBuilder?.selectedTextColor!!
}
mTextPaint.alpha = currentAlpha
canvas.drawText(
text, getXByPosition(i, textRect.width() / 2),
(mHeight / 2 + textRect.height() / 2) * mProcess,
mTextPaint
)
if (mProcess != 1f) {
mBitmapPaint.alpha = MAX_ALPHA - currentAlpha
canvas.drawBitmap(
bitmap, getXByPosition(i, bitmap.width / 2),
mHeight / 2 - bitmap.height / 2 + mProcess * mHeight,
mBitmapPaint
)
}
}
}
}
private fun drawSelctedTag(canvas: Canvas) {
canvas.drawCircle(
currentX + mProcessValus,
mHeight / 2.toFloat(),
(mRadius - 1).toFloat(),
mCiclePaint
) //item cicle
}
private fun drawbackGround(canvas: Canvas) {
if (mBuilder?.backgroundColor != 0) {
mBuilder?.backgroundColor?.let {
mBackgroundPaint.color = it
canvas.drawRoundRect(
mCicleRectF!!, mRadius.toFloat(), mRadius.toFloat(),
mBackgroundPaint
) // background
}
}
}
/**
*get current position by x
*/
private fun getXByPosition(i: Int, offSet: Int): Float {
return ((mWidth / itemCount) * i - (mWidth / itemCount) / 2 - offSet).toFloat()
}
/**
* get current position by x
*/
private fun getCurrentPositionByX(targetX: Int): Int {
return targetX / (mWidth / itemCount) + 1
}
/**
* anmate view
*/
private fun moveAnimation(toTargetX: Int) {
targetX = toTargetX
var totalValus = toTargetX - currentX
valueAnimator.setFloatValues(0f, totalValus.toFloat())
valueAnimator?.duration = ANIMATION_DURATION
valueAnimator?.start()
}
override fun onAnimationUpdate(animation: ValueAnimator) {
mProcessValus = animation.animatedValue as Float
if (mProcessValus != 0f) {
mProcess = mProcessValus / (targetX - currentX)
currentAlpha = (MAX_ALPHA * mProcess).toInt()
invalidate()
}
}
private var mGestureDetector: GestureDetector =
GestureDetector(context, object : GestureDetector.SimpleOnGestureListener() {
override fun onSingleTapUp(e: MotionEvent?): Boolean {
val clickX: Int = getTargetX(e!!.x)
Log.e(TAG, "$currentX click x $clickX")
if (!isMoving() && currentX != clickX) {
moveAnimation(clickX)
}
return true
}
});
override fun onTouchEvent(event: MotionEvent): Boolean {
Log.e(TAG, " event " + event.x)
mGestureDetector.onTouchEvent(event)
return true
}
fun setSelection(position: Int) {
var realPosition = position + 1
Log.e(TAG, realPosition.toString())
if (realPosition in 1 until itemCount + 1 && realPosition != currentPosition && !isMoving()) {
moveAnimation(getXByPosition(realPosition, 0).toInt())
}
}
class Builder(private val context: Context) {
var height = 120
var width = 0
var onItemClick: OnItemChangeLisenter? = null
var backgroundColor: Int = 0
var selectedTextColor: Int = 0
var unSelectedTextColor: Int = 0
lateinit var arrays: Array<String>
lateinit var images: Array<Int>
fun setOnItemClick(itemClick: OnItemChangeLisenter): Builder {
this.onItemClick = itemClick
return this
}
fun setBackgroundColor(color: Int): Builder {
backgroundColor = color
return this
}
fun setSelectedTextColor(color: Int): Builder {
selectedTextColor = color
return this
}
fun setUnSelectedTextColor(color: Int): Builder {
unSelectedTextColor = color
return this
}
fun setWidth(width: Int): Builder {
this.width = width
return this
}
fun setHeight(height: Int): Builder {
this.height = height
return this
}
fun setClick(click: OnItemChangeLisenter?): Builder {
this.onItemClick = click
return this
}
fun setArrays(arrays: Array<String>): Builder {
this.arrays = arrays
return this
}
fun setImages(images: Array<Int>): Builder {
this.images = images
return this
}
fun build(): AnimatedTabView {
val tabView = AnimatedTabView(context)
tabView.setBuilder(this@Builder)
return tabView
}
}
public fun setBuilder(builder: Builder?) {
mBuilder = builder
if (builder != null) notifyParamchanage()
}
private fun notifyParamchanage() {
if (mBuilder!!.arrays == null || mBuilder!!.images == null) {
return
}
itemCount = mBuilder!!.arrays.size.coerceAtMost(mBuilder!!.images.size)
mItemHeight = mBuilder!!.height
mHeight = mItemHeight + paddingTop + paddingBottom
mWidth = if (mBuilder!!.width == 0) {
mItemHeight * itemCount
} else {
mBuilder!!.width
}
mRadius = mItemHeight / 2
for (i in 0 until itemCount) {
val bitmap = sparseArray[i + 1]
if (bitmap == null) {
sparseArray.put(
i + 1,
BitmapFactory.decodeResource(resources, mBuilder!!.images[i])
)
}
}
postInvalidate()
}
interface OnItemChangeLisenter {
fun onItemSelected(position: Int)
}
}5、总结
a、你要 写一个动画 、并且 监听动画 执行过程 分别在动画 开始 及结束监听里 设置 view的各种状态 (所有动效类的 自定义View 都有这个共性)
b、按照动效 需求 去设置 绘制动效的 物理 特性
c、如图 动效需求 是 当tab 切换时 文字 和 图片都 需要 移动和 淡化 效果 我们 就利用一个 动画 来 实现 位移及 透明度 设置 。
d、只要你耐心点 你也可以写出 很优秀的 自定义组件。
内容总结
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