下面列出了怎么用android.util.FloatMath的API类实例代码及写法，或者点击链接到github查看源代码。
/**
* Determines the height of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
//We were told how big to be
result = specSize;
} else {
//Measure the height
result = mPaintSelected.getStrokeWidth() + getPaddingTop() + getPaddingBottom();
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the height of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
//We were told how big to be
result = specSize;
} else {
//Measure the height
result = mPaintSelected.getStrokeWidth() + getPaddingTop() + getPaddingBottom();
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the height of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
//We were told how big to be
result = specSize;
} else {
//Measure the height
result = mPaintSelected.getStrokeWidth() + getPaddingTop() + getPaddingBottom();
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
/**
* Determines the height of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
//We were told how big to be
result = specSize;
} else {
//Measure the height
result = mPaintSelected.getStrokeWidth() + getPaddingTop() + getPaddingBottom();
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
public static Bitmap getSampledBitmap(String filePath, int reqWidth, int reqHeight) {
Options options = new Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filePath, options);
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
if (width > height) {
inSampleSize = (int)FloatMath.floor(((float)height / reqHeight)+0.5f); //Math.round((float)height / (float)reqHeight);
} else {
inSampleSize = (int)FloatMath.floor(((float)width / reqWidth)+0.5f); //Math.round((float)width / (float)reqWidth);
}
}
options.inSampleSize = inSampleSize;
options.inJustDecodeBounds = false;
return BitmapFactory.decodeFile(filePath, options);
}
private static TextProperty computeTextProperty(final String string,
final int width, final int height, final Paint paint) {
final FontMetricsInt fm = paint.getFontMetricsInt();
final int h = (int) Math.ceil(fm.bottom - fm.top);
int maxContentWidth = 0;
final String[] lines = Cocos2dxBitmap.splitString(string, width,
height, paint);
if (width != 0) {
maxContentWidth = width;
} else {
/* Compute the max width. */
int temp = 0;
for (final String line : lines) {
temp = (int) FloatMath.ceil(paint.measureText(line, 0,
line.length()));
if (temp > maxContentWidth) {
maxContentWidth = temp;
}
}
}
return new TextProperty(maxContentWidth, h, lines);
}
/**
* Determines the width of this view
*
* @param measureSpec A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int) FloatMath.ceil(result);
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
private static TextProperty computeTextProperty(final String string,
final int width, final int height, final Paint paint) {
final FontMetricsInt fm = paint.getFontMetricsInt();
final int h = (int) Math.ceil(fm.bottom - fm.top);
int maxContentWidth = 0;
final String[] lines = Cocos2dxBitmap.splitString(string, width,
height, paint);
if (width != 0) {
maxContentWidth = width;
} else {
/* Compute the max width. */
int temp = 0;
for (final String line : lines) {
temp = (int) FloatMath.ceil(paint.measureText(line, 0,
line.length()));
if (temp > maxContentWidth) {
maxContentWidth = temp;
}
}
}
return new TextProperty(maxContentWidth, h, lines);
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
float result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
//We were told how big to be
result = specSize;
} else {
//Calculate the width according the views count
final int count = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)FloatMath.ceil(result);
}
public void onSensorChanged(SensorEvent event) {
long currentTime = System.currentTimeMillis();
long diffTime = currentTime - mLastUpdateTime;
if (diffTime > UPDATE_INTERVAL) {
if(mLastUpdateTime != 0) {
float x = event.values[0];
float y = event.values[1];
float z = event.values[2];
float deltaX = x - mLastX;
float deltaY = y - mLastY;
float deltaZ = z - mLastZ;
float delta = FloatMath.sqrt(deltaX * deltaX + deltaY * deltaY + deltaZ * deltaZ) / diffTime * 10000;
if (delta > SHAKE_THRESHOLD) {
if (!shaken) {
shaken = true;
finish();
}
if (listener != null) {
listener.onShake();
}
}
mLastX = x;
mLastY = y;
mLastZ = z;
}
mLastUpdateTime = currentTime;
}
}
/**calculate methods*/
protected PLPosition convertPitchAndYawToPosition(float pitch, float yaw)
{
float r = this.getZ(), pr = (90.0f - pitch) * PLConstants.kToRadians, yr = -yaw * PLConstants.kToRadians;
float x = r * FloatMath.sin(pr) * FloatMath.cos(yr);
float y = r * FloatMath.sin(pr) * FloatMath.sin(yr);
float z = r * FloatMath.cos(pr);
return PLPosition.PLPositionMake(y, z, x);
}
private float a(MotionEvent motionevent)
{
if (motionevent.getPointerCount() < 2)
{
return 0.0F;
} else
{
float f1 = motionevent.getX(0) - motionevent.getX(1);
float f2 = motionevent.getY(0) - motionevent.getY(1);
return FloatMath.sqrt(f1 * f1 + f2 * f2);
}
}
public void normalize()
{
float magnitude = (x * x + y * y + z * z);
if (magnitude == 0)
return;
float mult = (1.0f / FloatMath.sqrt(magnitude));
x *= mult;
y *= mult;
z *= mult;
}
public AmbilWarnaPrefWidgetView(Context context, AttributeSet attrs) {
super(context, attrs);
float density = context.getResources().getDisplayMetrics().density;
rectSize = FloatMath.floor(24.f * density + 0.5f);
strokeWidth = FloatMath.floor(1.f * density + 0.5f);
paint = new Paint();
paint.setColor(0xffffffff);
paint.setStyle(Style.STROKE);
paint.setStrokeWidth(strokeWidth);
}
/**
* 两点的距离
*/
@SuppressLint("FloatMath")
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
public float getSegmentLength(final int pSegmentIndex) {
final float[] coordinatesX = this.mXs;
final float[] coordinatesY = this.mYs;
final int nextSegmentIndex = pSegmentIndex + 1;
final float dx = coordinatesX[pSegmentIndex] - coordinatesX[nextSegmentIndex];
final float dy = coordinatesY[pSegmentIndex] - coordinatesY[nextSegmentIndex];
return FloatMath.sqrt(dx * dx + dy * dy);
}
/**
* Rotates p1 around p2 by angle degrees.
* @param p1
* @param p2
* @param angle
*/
public void rotate(PointF p1, PointF p2, float angle) {
float px = p1.x;
float py = p1.y;
float ox = p2.x;
float oy = p2.y;
p1.x = (FloatMath.cos(angle) * (px-ox) - FloatMath.sin(angle) * (py-oy) + ox);
p1.y = (FloatMath.sin(angle) * (px-ox) + FloatMath.cos(angle) * (py-oy) + oy);
}
public void onSensorChanged(SensorEvent event) {
long currentTime = System.currentTimeMillis();
long diffTime = currentTime - mLastUpdateTime;
if (diffTime > UPDATE_INTERVAL) {
if(mLastUpdateTime != 0) {
float x = event.values[0];
float y = event.values[1];
float z = event.values[2];
float deltaX = x - mLastX;
float deltaY = y - mLastY;
float deltaZ = z - mLastZ;
float delta = FloatMath.sqrt(deltaX * deltaX + deltaY * deltaY + deltaZ * deltaZ) / diffTime * 10000;
if (delta > SHAKE_THRESHOLD) { // 当加速度的差值大于指定的阈值，认为这是一个摇晃
if (!shaken) {
shaken = true;
finish();
}
if (listener != null) {
listener.onShake();
}
}
mLastX = x;
mLastY = y;
mLastZ = z;
}
mLastUpdateTime = currentTime;
}
}
public static BitmapSize getScaledSize(int originalWidth, int originalHeight, int numPixels) {
float ratio = (float)originalWidth/originalHeight;
int scaledHeight = (int)FloatMath.sqrt((float)numPixels/ratio);
int scaledWidth = (int)(ratio * FloatMath.sqrt((float)numPixels/ratio));
return new BitmapSize(scaledWidth, scaledHeight);
}
public static float[] rotateAroundCenter(final float[] pVertices, final float pRotation, final float pRotationCenterX, final float pRotationCenterY) {
if(pRotation != 0) {
final float rotationRad = MathUtils.degToRad(pRotation);
final float sinRotationRad = FloatMath.sin(rotationRad);
final float cosRotationInRad = FloatMath.cos(rotationRad);
for(int i = pVertices.length - 2; i >= 0; i -= 2) {
final float pX = pVertices[i];
final float pY = pVertices[i + 1];
pVertices[i] = pRotationCenterX + (cosRotationInRad * (pX - pRotationCenterX) - sinRotationRad * (pY - pRotationCenterY));
pVertices[i + 1] = pRotationCenterY + (sinRotationRad * (pX - pRotationCenterX) + cosRotationInRad * (pY - pRotationCenterY));
}
}
return pVertices;
}
@Override
public void onCreateInGLESThread() {
final int numOfVertices = (numBorderPoints+2) * 3;
final int numOfColors = (numBorderPoints+2) * 4;
// final int numOfTexCoords = (numBorderPoints+2) * 2;
final float[] vertices = new float[numOfVertices];
final float[] colors = new float[numOfColors];
final float[] normals = new float[numOfVertices];
// final float[] texCoords = new float[numOfTexCoords];
for (int i = 3, point = 0; i < numOfVertices; i += 3, point++) {
float radians = (float) Math.toRadians(360.f - point * 360.f / numBorderPoints);
vertices[i] = FloatMath.cos(radians);
vertices[i + 2] = FloatMath.sin(radians);
normals[i + 1] = 1.0f;
}
/** set color coordinates - first point is in the middle */
colors[0] = 1.0f;
colors[3] = 1.0f;
for (int i = 4; i < numOfColors; i += 4) {
colors[i] = 1.0f;
colors[i + 3] = 0.1f;
}
setRenderObjectives(vertices, colors, normals, null);
}
public static int computeSampleSizeLarger(float scale) {
int initialSize = (int) FloatMath.floor(1f / scale);
if (initialSize <= 1) return 1;
return initialSize <= 8
? Utils.prevPowerOf2(initialSize)
: initialSize / 8 * 8;
}
void init(CharSequence source,
TextPaint paint, int outerwidth,
Alignment align,
float spacingmult, float spacingadd,
BoringLayout.Metrics metrics, boolean includepad,
boolean trustWidth) {
int spacing;
if (source instanceof String && align == Layout.Alignment.ALIGN_NORMAL) {
mDirect = source.toString();
} else {
mDirect = null;
}
mPaint = paint;
if (includepad) {
spacing = metrics.bottom - metrics.top;
} else {
spacing = metrics.descent - metrics.ascent;
}
if (spacingmult != 1 || spacingadd != 0) {
spacing = (int)(spacing * spacingmult + spacingadd + 0.5f);
}
mBottom = spacing;
if (includepad) {
mDesc = spacing + metrics.top;
} else {
mDesc = spacing + metrics.ascent;
}
if (trustWidth) {
mMax = metrics.width;
} else {
/*
* If we have ellipsized, we have to actually calculate the
* width because the width that was passed in was for the
* full text, not the ellipsized form.
*/
synchronized (sTemp) {
mMax = (int) (FloatMath.ceil(Styled.measureText(paint, sTemp,
source, 0, source.length(),
null)));
}
}
if (includepad) {
mTopPadding = metrics.top - metrics.ascent;
mBottomPadding = metrics.bottom - metrics.descent;
}
}
/**
* Returns null if not boring; the width, ascent, and descent in the
* provided Metrics object (or a new one if the provided one was null)
* if boring.
*/
public static Metrics isBoring(CharSequence text, TextPaint paint,
Metrics metrics) {
char[] temp = TextUtils.obtain(500);
int len = text.length();
boolean boring = true;
outer:
for (int i = 0; i < len; i += 500) {
int j = i + 500;
if (j > len)
j = len;
TextUtils.getChars(text, i, j, temp, 0);
int n = j - i;
for (int a = 0; a < n; a++) {
char c = temp[a];
if (c == '\n' || c == '\t' || c >= FIRST_RIGHT_TO_LEFT) {
boring = false;
break outer;
}
}
}
TextUtils.recycle(temp);
if (boring && text instanceof Spanned) {
Spanned sp = (Spanned) text;
Object[] styles = sp.getSpans(0, text.length(), ParagraphStyle.class);
if (styles.length > 0) {
boring = false;
}
}
if (boring) {
Metrics fm = metrics;
if (fm == null) {
fm = new Metrics();
}
int wid;
synchronized (sTemp) {
wid = (int) (FloatMath.ceil(Styled.measureText(paint, sTemp,
text, 0, text.length(), fm)));
}
fm.width = wid;
return fm;
} else {
return null;
}
}
public static int dip2px(Context paramContext, float paramFloat) {
DisplayMetrics localDisplayMetrics = new DisplayMetrics();
((Activity) paramContext).getWindowManager().getDefaultDisplay().getMetrics(localDisplayMetrics);
return (int) FloatMath.ceil(localDisplayMetrics.density * paramFloat);
}