本文实例为大家分享了Android自定义View实现波浪动画的具体代码，供大家参考，具体内容如下
效果演示
代码调用与实现效果
xml中调用
android:layout_width="match_parent"
android:layout_height="match_parent"
app:amplitude="100"
app:quadrant="0.5"
app:speed="0.15"/>
实现原理
属性配置
attrs.xml文件中,进行属性配置
获取属性,同时对属性赋默认值
final TypedArray array = context.obtainStyledAttributes(set, R.styleable.Wave);
mSpeed = array.getFloat(R.styleable.Wave_speed, DEFAULT_SPEED);
mWaveColor = array.getColor(R.styleable.Wave_waveColor, DEFAULT_WAVE_COLOR);
mWaveBKColor = array.getColor(R.styleable.Wave_waveBackgroundColor, DEFAULT_WAVE_BK_COLOR);
mAmplitude = array.getInt(R.styleable.Wave_amplitude, DEFAULT_AMPLITUDE);
mQuadrant = array.getFloat(R.styleable.Wave_quadrant, DEFAULT_QUADRANT);
mFrequency = array.getFloat(R.styleable.Wave_frequency, DEFAULT_FREQUENCY);
array.recycle();
绘制波浪
在onDraw()中使用Canvas进行绘制即可,这里需要注意的正弦曲线的绘制.
正弦曲线(y=Asin(ωx+φ)+k)的一些参数如下:
A――振幅，当物体作轨迹符合正弦曲线的直线往复运动时，其值为行程的1/2。
(ωx+φ)――相位，反映变量y所处的状态。
φ――初相，x=0时的相位；反映在坐标系上则为图像的左右移动。
k――偏距，反映在坐标系上则为图像的上移或下移。
ω――角速度， 控制正弦周期(单位角度内震动的次数)。
onDraw中的代码:
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
final int width = getWidth();
final int height = getHeight();
final int waveHeight = (int) (getHeight() * mQuadrant);
// 绘制背景
canvas.drawColor(mWaveBKColor);
mWavePath.moveTo(0, height);
mWavePath.lineTo(0, waveHeight);
for (int i = 1; i <= width; i++) {
// 绘制正弦曲线 y = A Sin(ωt+ ρ) = A sin(2πft + ρ)
final float y = (float) (waveHeight + mAmplitude * Math.sin(2 * Math.PI * i * mFrequency + mShift));
mWavePath.lineTo(i, y);
}
// 将曲线闭合
mWavePath.lineTo(width, height);
canvas.drawPath(mWavePath, mWavePaint);
}
波浪动画
这时波浪应该已经绘制完成了,下面使用Handler中的周期任务实现动画效果.
// 创建一个周期任务,它的职责是改变正弦曲线的偏移量
final class WaveAnimation implements Runnable {
@Override
public void run() {
mWavePath.reset();
mShift += mSpeed;
invalidate();
Wave.this.postDelayed(this, DEFAULT_PERIOD);
}
}
在View被创建的时候让它进行执行
// 开始波浪动画
postDelayed(new WaveAnimation(), DEFAULT_PERIOD);
完整代码
public class Wave extends View {
// 默认属性值
private static final int DEFAULT_AMPLITUDE = 200;
private static final int DEFAULT_PERIOD = 16;
private static final float DEFAULT_SPEED = .1F;
private static final float DEFAULT_QUADRANT = .33F;
private static final float DEFAULT_FREQUENCY = 1F / 360F;
private static final int DEFAULT_WAVE_COLOR = Color.parseColor("#64B5F6");
private static final int DEFAULT_WAVE_BK_COLOR = Color.parseColor("#EEEEEE");
@SuppressWarnings("FieldCanBeLocal")
@ColorInt
private int mWaveColor;
@ColorInt
private int mWaveBKColor;
// 振幅
private int mAmplitude;
// 波浪位于View的位置
private float mQuadrant;
// 波浪的频率,这个值越大,波浪越密集
private float mFrequency;
// 速度
private float mSpeed;
private float mShift;
private final Paint mWavePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Path mWavePath = new Path();
public Wave(Context context) {
this(context, null);
}
public Wave(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public Wave(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context, attrs);
}
private void init(Context context, AttributeSet set) {
final TypedArray array = context.obtainStyledAttributes(set, R.styleable.Wave);
mSpeed = array.getFloat(R.styleable.Wave_speed, DEFAULT_SPEED);
mWaveColor = array.getColor(R.styleable.Wave_waveColor, DEFAULT_WAVE_COLOR);
mWaveBKColor = array.getColor(R.styleable.Wave_waveBackgroundColor, DEFAULT_WAVE_BK_COLOR);
mAmplitude = array.getInt(R.styleable.Wave_amplitude, DEFAULT_AMPLITUDE);
mQuadrant = array.getFloat(R.styleable.Wave_quadrant, DEFAULT_QUADRANT);
mFrequency = array.getFloat(R.styleable.Wave_frequency, DEFAULT_FREQUENCY);
array.recycle();
mWavePaint.setStrokeWidth(2);
mWavePaint.setColor(mWaveColor);
// 开始波浪动画
postDelayed(new WaveAnimation(), DEFAULT_PERIOD);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
final int width = getWidth();
final int height = getHeight();
final int waveHeight = (int) (getHeight() * mQuadrant);
// 绘制背景
canvas.drawColor(mWaveBKColor);
mWavePath.moveTo(0, height);
mWavePath.lineTo(0, waveHeight);
for (int i = 1; i <= width; i++) {
// 绘制正弦曲线 y = A Sin(ωt+ ρ) = A sin(2πft + ρ)
final float y = (float) (waveHeight + mAmplitude * Math.sin(2 * Math.PI * i * mFrequency + mShift));
mWavePath.lineTo(i, y);
}
// 将曲线闭合
mWavePath.lineTo(width, height);
canvas.drawPath(mWavePath, mWavePaint);
}
final class WaveAnimation implements Runnable {
@Override
public void run() {
mWavePath.reset();
mShift += mSpeed;
invalidate();
Wave.this.postDelayed(this, DEFAULT_PERIOD);
}
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持云海天教程。
原文链接：/y874961524/article/details/73546595
