Java tutorial
/* * Copyright (C) 2006 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.text.format; import android.annotation.NonNull; import android.annotation.Nullable; import android.annotation.UnsupportedAppUsage; import android.content.Context; import android.content.res.Resources; import android.icu.text.MeasureFormat; import android.icu.util.Measure; import android.icu.util.MeasureUnit; import android.net.NetworkUtils; import android.text.BidiFormatter; import android.text.TextUtils; import android.view.View; import java.util.Locale; /** * Utility class to aid in formatting common values that are not covered * by the {@link java.util.Formatter} class in {@link java.util} */ public final class Formatter { /** {@hide} */ public static final int FLAG_SHORTER = 1 << 0; /** {@hide} */ public static final int FLAG_CALCULATE_ROUNDED = 1 << 1; /** {@hide} */ public static final int FLAG_SI_UNITS = 1 << 2; /** {@hide} */ public static final int FLAG_IEC_UNITS = 1 << 3; /** {@hide} */ public static class BytesResult { public final String value; public final String units; public final long roundedBytes; public BytesResult(String value, String units, long roundedBytes) { this.value = value; this.units = units; this.roundedBytes = roundedBytes; } } private static Locale localeFromContext(@NonNull Context context) { return context.getResources().getConfiguration().getLocales().get(0); } /* Wraps the source string in bidi formatting characters in RTL locales */ private static String bidiWrap(@NonNull Context context, String source) { final Locale locale = localeFromContext(context); if (TextUtils.getLayoutDirectionFromLocale(locale) == View.LAYOUT_DIRECTION_RTL) { return BidiFormatter.getInstance(true /* RTL*/).unicodeWrap(source); } else { return source; } } /** * Formats a content size to be in the form of bytes, kilobytes, megabytes, etc. * * <p>As of O, the prefixes are used in their standard meanings in the SI system, so kB = 1000 * bytes, MB = 1,000,000 bytes, etc.</p> * * <p class="note">In {@link android.os.Build.VERSION_CODES#N} and earlier, powers of 1024 are * used instead, with KB = 1024 bytes, MB = 1,048,576 bytes, etc.</p> * * <p>If the context has a right-to-left locale, the returned string is wrapped in bidi * formatting characters to make sure it's displayed correctly if inserted inside a * right-to-left string. (This is useful in cases where the unit strings, like "MB", are * left-to-right, but the locale is right-to-left.)</p> * * @param context Context to use to load the localized units * @param sizeBytes size value to be formatted, in bytes * @return formatted string with the number */ public static String formatFileSize(@Nullable Context context, long sizeBytes) { if (context == null) { return ""; } final BytesResult res = formatBytes(context.getResources(), sizeBytes, FLAG_SI_UNITS); return bidiWrap(context, context.getString(com.android.internal.R.string.fileSizeSuffix, res.value, res.units)); } /** * Like {@link #formatFileSize}, but trying to generate shorter numbers * (showing fewer digits of precision). */ public static String formatShortFileSize(@Nullable Context context, long sizeBytes) { if (context == null) { return ""; } final BytesResult res = formatBytes(context.getResources(), sizeBytes, FLAG_SI_UNITS | FLAG_SHORTER); return bidiWrap(context, context.getString(com.android.internal.R.string.fileSizeSuffix, res.value, res.units)); } /** {@hide} */ @UnsupportedAppUsage public static BytesResult formatBytes(Resources res, long sizeBytes, int flags) { final int unit = ((flags & FLAG_IEC_UNITS) != 0) ? 1024 : 1000; final boolean isNegative = (sizeBytes < 0); float result = isNegative ? -sizeBytes : sizeBytes; int suffix = com.android.internal.R.string.byteShort; long mult = 1; if (result > 900) { suffix = com.android.internal.R.string.kilobyteShort; mult = unit; result = result / unit; } if (result > 900) { suffix = com.android.internal.R.string.megabyteShort; mult *= unit; result = result / unit; } if (result > 900) { suffix = com.android.internal.R.string.gigabyteShort; mult *= unit; result = result / unit; } if (result > 900) { suffix = com.android.internal.R.string.terabyteShort; mult *= unit; result = result / unit; } if (result > 900) { suffix = com.android.internal.R.string.petabyteShort; mult *= unit; result = result / unit; } // Note we calculate the rounded long by ourselves, but still let String.format() // compute the rounded value. String.format("%f", 0.1) might not return "0.1" due to // floating point errors. final int roundFactor; final String roundFormat; if (mult == 1 || result >= 100) { roundFactor = 1; roundFormat = "%.0f"; } else if (result < 1) { roundFactor = 100; roundFormat = "%.2f"; } else if (result < 10) { if ((flags & FLAG_SHORTER) != 0) { roundFactor = 10; roundFormat = "%.1f"; } else { roundFactor = 100; roundFormat = "%.2f"; } } else { // 10 <= result < 100 if ((flags & FLAG_SHORTER) != 0) { roundFactor = 1; roundFormat = "%.0f"; } else { roundFactor = 100; roundFormat = "%.2f"; } } if (isNegative) { result = -result; } final String roundedString = String.format(roundFormat, result); // Note this might overflow if abs(result) >= Long.MAX_VALUE / 100, but that's like 80PB so // it's okay (for now)... final long roundedBytes = (flags & FLAG_CALCULATE_ROUNDED) == 0 ? 0 : (((long) Math.round(result * roundFactor)) * mult / roundFactor); final String units = res.getString(suffix); return new BytesResult(roundedString, units, roundedBytes); } /** * Returns a string in the canonical IPv4 format ###.###.###.### from a packed integer * containing the IP address. The IPv4 address is expected to be in little-endian * format (LSB first). That is, 0x01020304 will return "4.3.2.1". * * @deprecated Use {@link java.net.InetAddress#getHostAddress()}, which supports both IPv4 and * IPv6 addresses. This method does not support IPv6 addresses. */ @Deprecated public static String formatIpAddress(int ipv4Address) { return NetworkUtils.intToInetAddress(ipv4Address).getHostAddress(); } private static final int SECONDS_PER_MINUTE = 60; private static final int SECONDS_PER_HOUR = 60 * 60; private static final int SECONDS_PER_DAY = 24 * 60 * 60; private static final int MILLIS_PER_MINUTE = 1000 * 60; /** * Returns elapsed time for the given millis, in the following format: * 1 day, 5 hr; will include at most two units, can go down to seconds precision. * @param context the application context * @param millis the elapsed time in milli seconds * @return the formatted elapsed time * @hide */ @UnsupportedAppUsage public static String formatShortElapsedTime(Context context, long millis) { long secondsLong = millis / 1000; int days = 0, hours = 0, minutes = 0; if (secondsLong >= SECONDS_PER_DAY) { days = (int) (secondsLong / SECONDS_PER_DAY); secondsLong -= days * SECONDS_PER_DAY; } if (secondsLong >= SECONDS_PER_HOUR) { hours = (int) (secondsLong / SECONDS_PER_HOUR); secondsLong -= hours * SECONDS_PER_HOUR; } if (secondsLong >= SECONDS_PER_MINUTE) { minutes = (int) (secondsLong / SECONDS_PER_MINUTE); secondsLong -= minutes * SECONDS_PER_MINUTE; } int seconds = (int) secondsLong; final Locale locale = localeFromContext(context); final MeasureFormat measureFormat = MeasureFormat.getInstance(locale, MeasureFormat.FormatWidth.SHORT); if (days >= 2 || (days > 0 && hours == 0)) { days += (hours + 12) / 24; return measureFormat.format(new Measure(days, MeasureUnit.DAY)); } else if (days > 0) { return measureFormat.formatMeasures(new Measure(days, MeasureUnit.DAY), new Measure(hours, MeasureUnit.HOUR)); } else if (hours >= 2 || (hours > 0 && minutes == 0)) { hours += (minutes + 30) / 60; return measureFormat.format(new Measure(hours, MeasureUnit.HOUR)); } else if (hours > 0) { return measureFormat.formatMeasures(new Measure(hours, MeasureUnit.HOUR), new Measure(minutes, MeasureUnit.MINUTE)); } else if (minutes >= 2 || (minutes > 0 && seconds == 0)) { minutes += (seconds + 30) / 60; return measureFormat.format(new Measure(minutes, MeasureUnit.MINUTE)); } else if (minutes > 0) { return measureFormat.formatMeasures(new Measure(minutes, MeasureUnit.MINUTE), new Measure(seconds, MeasureUnit.SECOND)); } else { return measureFormat.format(new Measure(seconds, MeasureUnit.SECOND)); } } /** * Returns elapsed time for the given millis, in the following format: * 1 day, 5 hr; will include at most two units, can go down to minutes precision. * @param context the application context * @param millis the elapsed time in milli seconds * @return the formatted elapsed time * @hide */ @UnsupportedAppUsage public static String formatShortElapsedTimeRoundingUpToMinutes(Context context, long millis) { long minutesRoundedUp = (millis + MILLIS_PER_MINUTE - 1) / MILLIS_PER_MINUTE; if (minutesRoundedUp == 0 || minutesRoundedUp == 1) { final Locale locale = localeFromContext(context); final MeasureFormat measureFormat = MeasureFormat.getInstance(locale, MeasureFormat.FormatWidth.SHORT); return measureFormat.format(new Measure(minutesRoundedUp, MeasureUnit.MINUTE)); } return formatShortElapsedTime(context, minutesRoundedUp * MILLIS_PER_MINUTE); } }