直播平台源代码，Android自定义View实现呼吸灯效果

自定义View

自定义 BreathView 的Kotlin代码如下：

<br>import android.animation.ValueAnimator<br>import android.animation.ValueAnimator.AnimatorUpdateListener<br>import android.content.Context<br>import android.graphics.Canvas<br>import android.graphics.Color<br>import android.graphics.Paint<br>import android.util.AttributeSet<br>import android.view.View<br>import android.view.animation.Animation<br>import android.view.animation.LinearInterpolator<br>class BreathView @JvmOverloads constructor(<br>    context: Context,<br>    attrs: AttributeSet? = null,<br>    defStyleAttr: Int = 0<br>) : View(context, attrs, defStyleAttr), AnimatorUpdateListener {<br>    private val mCenterCircleRadius: Float<br>    private var mMaxCircleRadius: Float<br>    private val mCirclePaint: Paint<br>    private var mAlphaValue = 0<br>    init {<br>        val a = context.obtainStyledAttributes(attrs, R.styleable.BreathView)<br>        mCenterCircleRadius = a.getDimension(R.styleable.BreathView_centerCircleRadius, 5f)<br>        mMaxCircleRadius = a.getDimension(R.styleable.BreathView_maxCircleRadius, 10f)<br>        if (mCenterCircleRadius >= mMaxCircleRadius) {<br>            mMaxCircleRadius = mCenterCircleRadius * 2<br>        }<br>        val circleColor = a.getColor(R.styleable.BreathView_circleColor, Color.GREEN)<br>        a.recycle()<br>        mCirclePaint = Paint()<br>        mCirclePaint.isAntiAlias = true<br>        mCirclePaint.style = Paint.Style.FILL<br>        mCirclePaint.color = circleColor<br>        val circleAlphaValueAnimator = ValueAnimator.ofInt(0, 255)<br>        circleAlphaValueAnimator.duration = BREATH_TIME<br>        circleAlphaValueAnimator.repeatCount = Animation.INFINITE<br>        circleAlphaValueAnimator.repeatMode = ValueAnimator.REVERSE<br>        circleAlphaValueAnimator.interpolator = LinearInterpolator()<br>        circleAlphaValueAnimator.addUpdateListener(this)<br>        circleAlphaValueAnimator.start()<br>    }<br>    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {<br>        super.onMeasure(widthMeasureSpec, heightMeasureSpec)<br>        var width = MeasureSpec.getSize(widthMeasureSpec)<br>        var height = MeasureSpec.getSize(heightMeasureSpec)<br>        val widthMode = MeasureSpec.getMode(widthMeasureSpec)<br>        val heightMode = MeasureSpec.getMode(widthMeasureSpec)<br>        if (widthMode == MeasureSpec.AT_MOST || widthMode == MeasureSpec.UNSPECIFIED) {<br>            width = Math.max(width.toFloat(), mMaxCircleRadius * 2).toInt()<br>        }<br>        if (heightMode == MeasureSpec.AT_MOST || heightMode == MeasureSpec.UNSPECIFIED) {<br>            height = Math.max(width.toFloat(), mMaxCircleRadius * 2).toInt()<br>        }<br>        setMeasuredDimension(width, height)<br>    }<br>    override fun draw(canvas: Canvas) {<br>        super.draw(canvas)<br>        val centerX = width / 2.0f<br>        val centerY = height / 2.0f<br>        mCirclePaint.alpha = 255<br>        canvas.drawCircle(centerX, centerY, mCenterCircleRadius, mCirclePaint)<br>        mCirclePaint.alpha = mAlphaValue<br>        canvas.drawCircle(centerX, centerY, mMaxCircleRadius, mCirclePaint)<br>    }<br>    override fun onAnimationUpdate(valueAnimator: ValueAnimator) {<br>        mAlphaValue = valueAnimator.animatedValue as Int<br>        invalidate()<br>    }<br>    companion object {<br>        private const val BREATH_TIME: Long = 1000 //动画执行时间/呼吸速率<br>    }<br>} 

自定义 BreathView 的Java代码如下：

<br>import android.animation.ValueAnimator;<br>import android.content.Context;<br>import android.content.res.TypedArray;<br>import android.graphics.Canvas;<br>import android.graphics.Color;<br>import android.graphics.Paint;<br>import android.util.AttributeSet;<br>import android.view.View;<br>import android.view.animation.Animation;<br>import android.view.animation.LinearInterpolator;<br>public class BreathView extends View implements ValueAnimator.AnimatorUpdateListener {<br>private static final long BREATH_TIME = 1000; //动画执行时间/呼吸速率<br>private final float mCenterCircleRadius;<br>private float mMaxCircleRadius;<br>private final Paint mCirclePaint;<br>private int mAlphaValue;<br>public BreathView(Context context) {<br>this(context, null);<br>}<br>public BreathView(Context context, AttributeSet attrs) {<br>this(context, attrs, 0);<br>}<br>public BreathView(Context context, AttributeSet attrs, int defStyleAttr) {<br>super(context, attrs, defStyleAttr);<br>final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.BreathView);<br>mCenterCircleRadius = a.getDimension(R.styleable.BreathView_centerCircleRadius, 5f);<br>mMaxCircleRadius = a.getDimension(R.styleable.BreathView_maxCircleRadius, 10f);<br>if (mCenterCircleRadius >= mMaxCircleRadius) {<br>mMaxCircleRadius = mCenterCircleRadius * 2;<br>}<br>int circleColor = a.getColor(R.styleable.BreathView_circleColor, Color.GREEN);<br>a.recycle();<br>mCirclePaint = new Paint();<br>mCirclePaint.setAntiAlias(true);<br>mCirclePaint.setStyle(Paint.Style.FILL);<br>mCirclePaint.setColor(circleColor);<br>ValueAnimator circleAlphaValueAnimator = ValueAnimator.ofInt(0, 255);<br>circleAlphaValueAnimator.setDuration(BREATH_TIME);<br>circleAlphaValueAnimator.setRepeatCount(Animation.INFINITE);<br>circleAlphaValueAnimator.setRepeatMode(ValueAnimator.REVERSE);<br>circleAlphaValueAnimator.setInterpolator(new LinearInterpolator());<br>circleAlphaValueAnimator.addUpdateListener(this);<br>circleAlphaValueAnimator.start();<br>}<br>@Override<br>protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {<br>super.onMeasure(widthMeasureSpec, heightMeasureSpec);<br>int width = MeasureSpec.getSize(widthMeasureSpec);<br>int height = MeasureSpec.getSize(heightMeasureSpec);<br>int widthMode = MeasureSpec.getMode(widthMeasureSpec);<br>int heightMode = MeasureSpec.getMode(widthMeasureSpec);<br>if(widthMode == MeasureSpec.AT_MOST || widthMode == MeasureSpec.UNSPECIFIED) {<br>width = (int) Math.max(width, mMaxCircleRadius * 2);<br>}<br>if(heightMode == MeasureSpec.AT_MOST || heightMode == MeasureSpec.UNSPECIFIED) {<br>            height = (int) Math.max(width, mMaxCircleRadius * 2);<br>        }<br>setMeasuredDimension(width, height);<br>}<br>@Override<br>public void draw(Canvas canvas) {<br>        super.draw(canvas);<br>float centerX = getWidth() / 2.0f;<br>float centerY = getHeight() / 2.0f;<br>mCirclePaint.setAlpha(255);<br>canvas.drawCircle(centerX, centerY, mCenterCircleRadius, mCirclePaint);<br>mCirclePaint.setAlpha(mAlphaValue);<br>canvas.drawCircle(centerX, centerY, mMaxCircleRadius, mCirclePaint);<br>}<br>@Override<br>public void onAnimationUpdate(ValueAnimator valueAnimator) {<br>mAlphaValue = (int) valueAnimator.getAnimatedValue();<br>invalidate();<br>}<br>}