Android 框架：快速开发中Util常用工具类总结
来源：互联网 发布：淘宝 3d试衣 编辑：程序博客网 时间：2024/06/04 19:39
一、日志工具类 L.java
public class L { private L() { /* 不可被实例化 */ throw new UnsupportedOperationException("Cannot be instantiated!"); } // 是否需要打印bug，可以在application的onCreate函数里面初始化 public static boolean isDebug = true; private static final String TAG = "DefaultTag"; // 下面四个是默认tag的函数 public static void i(String msg) { if (isDebug) Log.i(TAG, msg); } public static void d(String msg) { if (isDebug) Log.d(TAG, msg); } public static void e(String msg) { if (isDebug) Log.e(TAG, msg); } public static void v(String msg) { if (isDebug) Log.v(TAG, msg); } // 下面是传入自定义tag的函数 public static void i(String tag, String msg) { if (isDebug) Log.i(tag, msg); } public static void d(String tag, String msg) { if (isDebug) Log.i(tag, msg); } public static void e(String tag, String msg) { if (isDebug) Log.i(tag, msg); } public static void v(String tag, String msg) { if (isDebug) Log.i(tag, msg); } } 网上也有很多提供把日志记录到SDCard上的，根据需求使用。
二、Toast统一管理类 T.java
public class T { private T() { /* cannot be instantiated */ throw new UnsupportedOperationException("cannot be instantiated"); } public static boolean isShow = true; /** * 短时间显示Toast */ public static void showShort(Context context, CharSequence message) { if (isShow) Toast.makeText(context, message, Toast.LENGTH_SHORT).show(); } /** * 短时间显示Toast * @param message 要显示的字符串资源的id */ public static void showShort(Context context, int message) { if (isShow) Toast.makeText(context, message, Toast.LENGTH_SHORT).show(); } /** * 长时间显示Toast */ public static void showLong(Context context, CharSequence message) { if (isShow) Toast.makeText(context, message, Toast.LENGTH_LONG).show(); } /** * 长时间显示Toast */ public static void showLong(Context context, int message) { if (isShow) Toast.makeText(context, message, Toast.LENGTH_LONG).show(); } /** * 自定义显示Toast时间 */ public static void show(Context context, CharSequence message, int duration) { if (isShow) Toast.makeText(context, message, duration).show(); } /** * 自定义显示Toast时间 */ public static void show(Context context, int message, int duration) { if (isShow) Toast.makeText(context, message, duration).show(); } } 三、SharedPreferences封装类 SPUtils.java 和 PreferencesUtils.java
1. SPUtils.java
public class SPUtils { /** * 保存在手机里面的文件名 */ public static final String FILE_NAME = "share_data"; /** * 保存数据的方法，我们需要拿到保存数据的具体类型，然后根据类型调用不同的保存方法 * * @param context * @param key * @param object */ public static void put(Context context, String key, Object object) { SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = sp.edit(); if (object instanceof String) { editor.putString(key, (String) object); } else if (object instanceof Integer) { editor.putInt(key, (Integer) object); } else if (object instanceof Boolean) { editor.putBoolean(key, (Boolean) object); } else if (object instanceof Float) { editor.putFloat(key, (Float) object); } else if (object instanceof Long) { editor.putLong(key, (Long) object); } else { editor.putString(key, object.toString()); } SharedPreferencesCompat.apply(editor); } /** * 得到保存数据的方法，我们根据默认值得到保存的数据的具体类型，然后调用相对于的方法获取值 * * @param context * @param key * @param defaultObject * @return */ public static Object get(Context context, String key, Object defaultObject) { SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE); if (defaultObject instanceof String) { return sp.getString(key, (String) defaultObject); } else if (defaultObject instanceof Integer) { return sp.getInt(key, (Integer) defaultObject); } else if (defaultObject instanceof Boolean) { return sp.getBoolean(key, (Boolean) defaultObject); } else if (defaultObject instanceof Float) { return sp.getFloat(key, (Float) defaultObject); } else if (defaultObject instanceof Long) { return sp.getLong(key, (Long) defaultObject); } return null; } /** * 移除某个key值已经对应的值 * @param context * @param key */ public static void remove(Context context, String key) { SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = sp.edit(); editor.remove(key); SharedPreferencesCompat.apply(editor); } /** * 清除所有数据 * @param context */ public static void clear(Context context) { SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = sp.edit(); editor.clear(); SharedPreferencesCompat.apply(editor); } /** * 查询某个key是否已经存在 * @param context * @param key * @return */ public static boolean contains(Context context, String key) { SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE); return sp.contains(key); } /** * 返回所有的键值对 * * @param context * @return */ public static Map<String, ?> getAll(Context context) { SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE); return sp.getAll(); } /** * 创建一个解决SharedPreferencesCompat.apply方法的一个兼容类 * * @author zhy * */ private static class SharedPreferencesCompat { private static final Method sApplyMethod = findApplyMethod(); /** * 反射查找apply的方法 * * @return */ @SuppressWarnings({ "unchecked", "rawtypes" }) private static Method findApplyMethod() { try { Class clz = SharedPreferences.Editor.class; return clz.getMethod("apply"); } catch (NoSuchMethodException e) { } return null; } /** * 如果找到则使用apply执行，否则使用commit * * @param editor */ public static void apply(SharedPreferences.Editor editor) { try { if (sApplyMethod != null) { sApplyMethod.invoke(editor); return; } } catch (IllegalArgumentException e) { } catch (IllegalAccessException e) { } catch (InvocationTargetException e) { } editor.commit(); } } } 对SharedPreference的使用做了建议的封装，对外公布出put，get，remove，clear等等方法；
- 注意一点，里面所有的commit操作使用了SharedPreferencesCompat.apply进行了替代，目的是尽可能的使用apply代替commit.
- 首先说下为什么，因为commit方法是同步的，并且我们很多时候的commit操作都是UI线程中，毕竟是IO操作，尽可能异步；
- 所以我们使用apply进行替代，apply异步的进行写入；
- 但是apply相当于commit来说是new API呢，为了更好的兼容，我们做了适配；
- SharedPreferencesCompat也可以给大家创建兼容类提供了一定的参考~~
2. SPUtils.java
public class PreferencesUtils { public static String PREFERENCE_NAME = "TrineaAndroidCommon"; private PreferencesUtils() { throw new AssertionError(); } /** * put string preferences * * @param context * @param key The name of the preference to modify * @param value The new value for the preference * @return True if the new values were successfully written to persistent storage. */ public static boolean putString(Context context, String key, String value) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = settings.edit(); editor.putString(key, value); return editor.commit(); } /** * get string preferences * * @param context * @param key The name of the preference to retrieve * @return The preference value if it exists, or null. Throws ClassCastException if there is a preference with this * name that is not a string * @see #getString(Context, String, String) */ public static String getString(Context context, String key) { return getString(context, key, null); } /** * get string preferences * * @param context * @param key The name of the preference to retrieve * @param defaultValue Value to return if this preference does not exist * @return The preference value if it exists, or defValue. Throws ClassCastException if there is a preference with * this name that is not a string */ public static String getString(Context context, String key, String defaultValue) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); return settings.getString(key, defaultValue); } /** * put int preferences * * @param context * @param key The name of the preference to modify * @param value The new value for the preference * @return True if the new values were successfully written to persistent storage. */ public static boolean putInt(Context context, String key, int value) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = settings.edit(); editor.putInt(key, value); return editor.commit(); } /** * get int preferences * * @param context * @param key The name of the preference to retrieve * @return The preference value if it exists, or -1. Throws ClassCastException if there is a preference with this * name that is not a int * @see #getInt(Context, String, int) */ public static int getInt(Context context, String key) { return getInt(context, key, -1); } /** * get int preferences * * @param context * @param key The name of the preference to retrieve * @param defaultValue Value to return if this preference does not exist * @return The preference value if it exists, or defValue. Throws ClassCastException if there is a preference with * this name that is not a int */ public static int getInt(Context context, String key, int defaultValue) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); return settings.getInt(key, defaultValue); } /** * put long preferences * * @param context * @param key The name of the preference to modify * @param value The new value for the preference * @return True if the new values were successfully written to persistent storage. */ public static boolean putLong(Context context, String key, long value) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = settings.edit(); editor.putLong(key, value); return editor.commit(); } /** * get long preferences * * @param context * @param key The name of the preference to retrieve * @return The preference value if it exists, or -1. Throws ClassCastException if there is a preference with this * name that is not a long * @see #getLong(Context, String, long) */ public static long getLong(Context context, String key) { return getLong(context, key, -1); } /** * get long preferences * * @param context * @param key The name of the preference to retrieve * @param defaultValue Value to return if this preference does not exist * @return The preference value if it exists, or defValue. Throws ClassCastException if there is a preference with * this name that is not a long */ public static long getLong(Context context, String key, long defaultValue) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); return settings.getLong(key, defaultValue); } /** * put float preferences * * @param context * @param key The name of the preference to modify * @param value The new value for the preference * @return True if the new values were successfully written to persistent storage. */ public static boolean putFloat(Context context, String key, float value) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = settings.edit(); editor.putFloat(key, value); return editor.commit(); } /** * get float preferences * * @param context * @param key The name of the preference to retrieve * @return The preference value if it exists, or -1. Throws ClassCastException if there is a preference with this * name that is not a float * @see #getFloat(Context, String, float) */ public static float getFloat(Context context, String key) { return getFloat(context, key, -1); } /** * get float preferences * * @param context * @param key The name of the preference to retrieve * @param defaultValue Value to return if this preference does not exist * @return The preference value if it exists, or defValue. Throws ClassCastException if there is a preference with * this name that is not a float */ public static float getFloat(Context context, String key, float defaultValue) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); return settings.getFloat(key, defaultValue); } /** * put boolean preferences * * @param context * @param key The name of the preference to modify * @param value The new value for the preference * @return True if the new values were successfully written to persistent storage. */ public static boolean putBoolean(Context context, String key, boolean value) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); SharedPreferences.Editor editor = settings.edit(); editor.putBoolean(key, value); return editor.commit(); } /** * get boolean preferences, default is false * * @param context * @param key The name of the preference to retrieve * @return The preference value if it exists, or false. Throws ClassCastException if there is a preference with this * name that is not a boolean * @see #getBoolean(Context, String, boolean) */ public static boolean getBoolean(Context context, String key) { return getBoolean(context, key, false); } /** * get boolean preferences * * @param context * @param key The name of the preference to retrieve * @param defaultValue Value to return if this preference does not exist * @return The preference value if it exists, or defValue. Throws ClassCastException if there is a preference with * this name that is not a boolean */ public static boolean getBoolean(Context context, String key, boolean defaultValue) { SharedPreferences settings = context.getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE); return settings.getBoolean(key, defaultValue); }}四、单位转换类 DensityUtils.java
public class DensityUtils { private DensityUtils() { /* cannot be instantiated */ throw new UnsupportedOperationException("cannot be instantiated"); } /** * dp转px * * @param context * @param val * @return */ public static int dp2px(Context context, float dpVal) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpVal, context.getResources().getDisplayMetrics()); } /** * sp转px * * @param context * @param val * @return */ public static int sp2px(Context context, float spVal) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, spVal, context.getResources().getDisplayMetrics()); } /** * px转dp * * @param context * @param pxVal * @return */ public static float px2dp(Context context, float pxVal) { final float scale = context.getResources().getDisplayMetrics().density; return (pxVal / scale); } /** * px转sp * * @param fontScale * @param pxVal * @return */ public static float px2sp(Context context, float pxVal) { return (pxVal / context.getResources().getDisplayMetrics().scaledDensity); } } TypedValue：
Container for a dynamically typed data value. Primarily used with Resources for holding resource values.applyDimension(int unit, float value, DisplayMetrics metrics)：
Converts an unpacked complex data value holding a dimension to its final floating point value.
五、SD卡相关辅助类 SDCardUtils.java
public class SDCardUtils { private SDCardUtils() { /* cannot be instantiated */ throw new UnsupportedOperationException("cannot be instantiated"); } /** * 判断SDCard是否可用 * * @return */ public static boolean isSDCardEnable() { return Environment.getExternalStorageState().equals( Environment.MEDIA_MOUNTED); } /** * 获取SD卡路径 * * @return */ public static String getSDCardPath() { return Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator; } /** * 获取SD卡的剩余容量 单位byte * * @return */ public static long getSDCardAllSize() { if (isSDCardEnable()) { StatFs stat = new StatFs(getSDCardPath()); // 获取空闲的数据块的数量 long availableBlocks = (long) stat.getAvailableBlocks() - 4; // 获取单个数据块的大小（byte） long freeBlocks = stat.getAvailableBlocks(); return freeBlocks * availableBlocks; } return 0; } /** * 获取指定路径所在空间的剩余可用容量字节数，单位byte * * @param filePath * @return 容量字节 SDCard可用空间，内部存储可用空间 */ public static long getFreeBytes(String filePath) { // 如果是sd卡的下的路径，则获取sd卡可用容量 if (filePath.startsWith(getSDCardPath())) { filePath = getSDCardPath(); } else {// 如果是内部存储的路径，则获取内存存储的可用容量 filePath = Environment.getDataDirectory().getAbsolutePath(); } StatFs stat = new StatFs(filePath); long availableBlocks = (long) stat.getAvailableBlocks() - 4; return stat.getBlockSize() * availableBlocks; } /** * 获取系统存储路径 * * @return */ public static String getRootDirectoryPath() { return Environment.getRootDirectory().getAbsolutePath(); } } StatFs是Android提供的一个类：
Retrieve overall information about the space on a filesystem. This is a wrapper for Unix statvfs().
检索一个文件系统的整体信息空间。这是一个Unix statvfs() 包装器。
六、屏幕相关辅助类 ScreenUtils.java
public class ScreenUtils { private ScreenUtils() { /* cannot be instantiated */ throw new UnsupportedOperationException("cannot be instantiated"); } /** * 获得屏幕高度 * * @param context * @return */ public static int getScreenWidth(Context context) { WindowManager wm = (WindowManager) context .getSystemService(Context.WINDOW_SERVICE); DisplayMetrics outMetrics = new DisplayMetrics(); wm.getDefaultDisplay().getMetrics(outMetrics); return outMetrics.widthPixels; } /** * 获得屏幕宽度 * * @param context * @return */ public static int getScreenHeight(Context context) { WindowManager wm = (WindowManager) context .getSystemService(Context.WINDOW_SERVICE); DisplayMetrics outMetrics = new DisplayMetrics(); wm.getDefaultDisplay().getMetrics(outMetrics); return outMetrics.heightPixels; } /** * 获得状态栏的高度 * * @param context * @return */ public static int getStatusHeight(Context context) { int statusHeight = -1; try { Class<?> clazz = Class.forName("com.android.internal.R$dimen"); Object object = clazz.newInstance(); int height = Integer.parseInt(clazz.getField("status_bar_height") .get(object).toString()); statusHeight = context.getResources().getDimensionPixelSize(height); } catch (Exception e) { e.printStackTrace(); } return statusHeight; } /** * 获取当前屏幕截图，包含状态栏 * * @param activity * @return */ public static Bitmap snapShotWithStatusBar(Activity activity) { View view = activity.getWindow().getDecorView(); view.setDrawingCacheEnabled(true); view.buildDrawingCache(); Bitmap bmp = view.getDrawingCache(); int width = getScreenWidth(activity); int height = getScreenHeight(activity); Bitmap bp = null; bp = Bitmap.createBitmap(bmp, 0, 0, width, height); view.destroyDrawingCache(); return bp; } /** * 获取当前屏幕截图，不包含状态栏 * * @param activity * @return */ public static Bitmap snapShotWithoutStatusBar(Activity activity) { View view = activity.getWindow().getDecorView(); view.setDrawingCacheEnabled(true); view.buildDrawingCache(); Bitmap bmp = view.getDrawingCache(); Rect frame = new Rect(); activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame); int statusBarHeight = frame.top; int width = getScreenWidth(activity); int height = getScreenHeight(activity); Bitmap bp = null; bp = Bitmap.createBitmap(bmp, 0, statusBarHeight, width, height - statusBarHeight); view.destroyDrawingCache(); return bp; } } 七、App相关辅助类 APPUtils.java
public class AppUtils { private AppUtils() { /* cannot be instantiated */ throw new UnsupportedOperationException("cannot be instantiated"); } /** * 获取应用程序名称 */ public static String getAppName(Context context) { try { PackageManager packageManager = context.getPackageManager(); PackageInfo packageInfo = packageManager.getPackageInfo( context.getPackageName(), 0); int labelRes = packageInfo.applicationInfo.labelRes; return context.getResources().getString(labelRes); } catch (NameNotFoundException e) { e.printStackTrace(); } return null; } /** * [获取应用程序版本名称信息] * * @param context * @return 当前应用的版本名称 */ public static String getVersionName(Context context) { try { PackageManager packageManager = context.getPackageManager(); PackageInfo packageInfo = packageManager.getPackageInfo( context.getPackageName(), 0); return packageInfo.versionName; } catch (NameNotFoundException e) { e.printStackTrace(); } return null; } } 八、软键盘相关辅助类KeyBoardUtils.java
/** * 打开或关闭软键盘 */ public class KeyBoardUtils { /** * 打卡软键盘 * * @param mEditText 输入框 * @param mContext 上下文 */ public static void openKeybord(EditText mEditText, Context mContext) { InputMethodManager imm = (InputMethodManager) mContext .getSystemService(Context.INPUT_METHOD_SERVICE); imm.showSoftInput(mEditText, InputMethodManager.RESULT_SHOWN); imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, InputMethodManager.HIDE_IMPLICIT_ONLY); } /** * 关闭软键盘 * * @param mEditText 输入框 * @param mContext 上下文 */ public static void closeKeybord(EditText mEditText, Context mContext) { InputMethodManager imm = (InputMethodManager) mContext .getSystemService(Context.INPUT_METHOD_SERVICE); imm.hideSoftInputFromWindow(mEditText.getWindowToken(), 0); } } 九、网络相关辅助类 NetUtils.java
public class NetUtils { private NetUtils() { /* cannot be instantiated */ throw new UnsupportedOperationException("cannot be instantiated"); } /** * 判断网络是否连接 */ public static boolean isConnected(Context context) { ConnectivityManager connectivity = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); if (null != connectivity) { NetworkInfo info = connectivity.getActiveNetworkInfo(); if (null != info && info.isConnected()) { if (info.getState() == NetworkInfo.State.CONNECTED) { return true; } } } return false; } /** * 判断是否是wifi连接 */ public static boolean isWifi(Context context) { ConnectivityManager cm = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); if (cm == null) return false; return cm.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI; } /** * 打开网络设置界面 */ public static void openSetting(Activity activity) { Intent intent = new Intent("/"); ComponentName cm = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings"); intent.setComponent(cm); intent.setAction("android.intent.action.VIEW"); activity.startActivityForResult(intent, 0); } } 十、Http相关辅助类 HttpUtils.java
/** * Http请求的工具类 */public class HttpUtils { private static final int TIMEOUT_IN_MILLIONS = 5000; public interface CallBack { void onRequestComplete(String result); } /** * 异步的Get请求 * * @param urlStr * @param callBack */ public static void doGetAsyn(final String urlStr, final CallBack callBack) { new Thread() { public void run() { try { String result = doGet(urlStr); if (callBack != null) { callBack.onRequestComplete(result); } } catch (Exception e) { e.printStackTrace(); } }; }.start(); } /** * 异步的Post请求 * @param urlStr * @param params * @param callBack * @throws Exception */ public static void doPostAsyn(final String urlStr, final String params, final CallBack callBack) throws Exception { new Thread() { public void run() { try { String result = doPost(urlStr, params); if (callBack != null) { callBack.onRequestComplete(result); } } catch (Exception e) { e.printStackTrace(); } }; }.start(); } /** * Get请求，获得返回数据 * * @param urlStr * @return * @throws Exception */ public static String doGet(String urlStr) { URL url = null; HttpURLConnection conn = null; InputStream is = null; ByteArrayOutputStream baos = null; try { url = new URL(urlStr); conn = (HttpURLConnection) url.openConnection(); conn.setReadTimeout(TIMEOUT_IN_MILLIONS); conn.setConnectTimeout(TIMEOUT_IN_MILLIONS); conn.setRequestMethod("GET"); conn.setRequestProperty("accept", "*/*"); conn.setRequestProperty("connection", "Keep-Alive"); if (conn.getResponseCode() == 200) { is = conn.getInputStream(); baos = new ByteArrayOutputStream(); int len = -1; byte[] buf = new byte[128]; while ((len = is.read(buf)) != -1) { baos.write(buf, 0, len); } baos.flush(); return baos.toString(); } else { throw new RuntimeException(" responseCode is not 200 ... "); } } catch (Exception e) { e.printStackTrace(); } finally { try { if (is != null) is.close(); } catch (IOException e) { } try { if (baos != null) baos.close(); } catch (IOException e) { } conn.disconnect(); } return null ; } /** * 向指定 URL 发送POST方法的请求 * * @param url * 发送请求的 URL * @param param * 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。 * @return 所代表远程资源的响应结果 * @throws Exception */ public static String doPost(String url, String param) { PrintWriter out = null; BufferedReader in = null; String result = ""; try { URL realUrl = new URL(url); // 打开和URL之间的连接 HttpURLConnection conn = (HttpURLConnection) realUrl .openConnection(); // 设置通用的请求属性 conn.setRequestProperty("accept", "*/*"); conn.setRequestProperty("connection", "Keep-Alive"); conn.setRequestMethod("POST"); conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); conn.setRequestProperty("charset", "utf-8"); conn.setUseCaches(false); // 发送POST请求必须设置如下两行 conn.setDoOutput(true); conn.setDoInput(true); conn.setReadTimeout(TIMEOUT_IN_MILLIONS); conn.setConnectTimeout(TIMEOUT_IN_MILLIONS); if (param != null && !param.trim().equals("")) { // 获取URLConnection对象对应的输出流 out = new PrintWriter(conn.getOutputStream()); // 发送请求参数 out.print(param); // flush输出流的缓冲 out.flush(); } // 定义BufferedReader输入流来读取URL的响应 in = new BufferedReader( new InputStreamReader(conn.getInputStream())); String line; while ((line = in.readLine()) != null) { result += line; } } catch (Exception e) { e.printStackTrace(); } // 使用finally块来关闭输出流、输入流 finally { try { if (out != null) { out.close(); } if (in != null) { in.close(); } } catch (IOException ex) { ex.printStackTrace(); } } return result; } } 十一、时间工具类 TimeUtils.java
public class TimeUtils { public static final SimpleDateFormat DEFAULT_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); public static final SimpleDateFormat DATE_FORMAT_DATE = new SimpleDateFormat("yyyy-MM-dd"); private TimeUtils() { throw new AssertionError(); } /** * long time to string * * @param timeInMillis * @param dateFormat * @return */ public static String getTime(long timeInMillis, SimpleDateFormat dateFormat) { return dateFormat.format(new Date(timeInMillis)); } /** * long time to string, format is {@link #DEFAULT_DATE_FORMAT} * * @param timeInMillis * @return */ public static String getTime(long timeInMillis) { return getTime(timeInMillis, DEFAULT_DATE_FORMAT); } /** * get current time in milliseconds * * @return */ public static long getCurrentTimeInLong() { return System.currentTimeMillis(); } /** * get current time in milliseconds, format is {@link #DEFAULT_DATE_FORMAT} * * @return */ public static String getCurrentTimeInString() { return getTime(getCurrentTimeInLong()); } /** * get current time in milliseconds * * @return */ public static String getCurrentTimeInString(SimpleDateFormat dateFormat) { return getTime(getCurrentTimeInLong(), dateFormat); }}十二、文件工具类 FileUtils.java
public class FileUtils { public final static String FILE_EXTENSION_SEPARATOR = "."; private FileUtils() { throw new AssertionError(); } /** * read file * * @param filePath * @param charsetName The name of a supported {@link java.nio.charset.Charset </code>charset<code>} * @return if file not exist, return null, else return content of file * @throws RuntimeException if an error occurs while operator BufferedReader */ public static StringBuilder readFile(String filePath, String charsetName) { File file = new File(filePath); StringBuilder fileContent = new StringBuilder(""); if (file == null || !file.isFile()) { return null; } BufferedReader reader = null; try { InputStreamReader is = new InputStreamReader(new FileInputStream(file), charsetName); reader = new BufferedReader(is); String line = null; while ((line = reader.readLine()) != null) { if (!fileContent.toString().equals("")) { fileContent.append("\r\n"); } fileContent.append(line); } return fileContent; } catch (IOException e) { throw new RuntimeException("IOException occurred. ", e); } finally { IOUtils.close(reader); } } /** * write file * * @param filePath * @param content * @param append is append, if true, write to the end of file, else clear content of file and write into it * @return return false if content is empty, true otherwise * @throws RuntimeException if an error occurs while operator FileWriter */ public static boolean writeFile(String filePath, String content, boolean append) { if (StringUtils.isEmpty(content)) { return false; } FileWriter fileWriter = null; try { makeDirs(filePath); fileWriter = new FileWriter(filePath, append); fileWriter.write(content); return true; } catch (IOException e) { throw new RuntimeException("IOException occurred. ", e); } finally { IOUtils.close(fileWriter); } } /** * write file * * @param filePath * @param contentList * @param append is append, if true, write to the end of file, else clear content of file and write into it * @return return false if contentList is empty, true otherwise * @throws RuntimeException if an error occurs while operator FileWriter */ public static boolean writeFile(String filePath, List<String> contentList, boolean append) { if (ListUtils.isEmpty(contentList)) { return false; } FileWriter fileWriter = null; try { makeDirs(filePath); fileWriter = new FileWriter(filePath, append); int i = 0; for (String line : contentList) { if (i++ > 0) { fileWriter.write("\r\n"); } fileWriter.write(line); } return true; } catch (IOException e) { throw new RuntimeException("IOException occurred. ", e); } finally { IOUtils.close(fileWriter); } } /** * write file, the string will be written to the begin of the file * * @param filePath * @param content * @return */ public static boolean writeFile(String filePath, String content) { return writeFile(filePath, content, false); } /** * write file, the string list will be written to the begin of the file * * @param filePath * @param contentList * @return */ public static boolean writeFile(String filePath, List<String> contentList) { return writeFile(filePath, contentList, false); } /** * write file, the bytes will be written to the begin of the file * * @param filePath * @param stream * @return * @see {@link #writeFile(String, InputStream, boolean)} */ public static boolean writeFile(String filePath, InputStream stream) { return writeFile(filePath, stream, false); } /** * write file * * @param file the file to be opened for writing. * @param stream the input stream * @param append if <code>true</code>, then bytes will be written to the end of the file rather than the beginning * @return return true * @throws RuntimeException if an error occurs while operator FileOutputStream */ public static boolean writeFile(String filePath, InputStream stream, boolean append) { return writeFile(filePath != null ? new File(filePath) : null, stream, append); } /** * write file, the bytes will be written to the begin of the file * * @param file * @param stream * @return * @see {@link #writeFile(File, InputStream, boolean)} */ public static boolean writeFile(File file, InputStream stream) { return writeFile(file, stream, false); } /** * write file * * @param file the file to be opened for writing. * @param stream the input stream * @param append if <code>true</code>, then bytes will be written to the end of the file rather than the beginning * @return return true * @throws RuntimeException if an error occurs while operator FileOutputStream */ public static boolean writeFile(File file, InputStream stream, boolean append) { OutputStream o = null; try { makeDirs(file.getAbsolutePath()); o = new FileOutputStream(file, append); byte data[] = new byte[1024]; int length = -1; while ((length = stream.read(data)) != -1) { o.write(data, 0, length); } o.flush(); return true; } catch (FileNotFoundException e) { throw new RuntimeException("FileNotFoundException occurred. ", e); } catch (IOException e) { throw new RuntimeException("IOException occurred. ", e); } finally { IOUtils.close(o); IOUtils.close(stream); } } /** * move file * * @param sourceFilePath * @param destFilePath */ public static void moveFile(String sourceFilePath, String destFilePath) { if (TextUtils.isEmpty(sourceFilePath) || TextUtils.isEmpty(destFilePath)) { throw new RuntimeException("Both sourceFilePath and destFilePath cannot be null."); } moveFile(new File(sourceFilePath), new File(destFilePath)); } /** * move file * * @param srcFile * @param destFile */ public static void moveFile(File srcFile, File destFile) { boolean rename = srcFile.renameTo(destFile); if (!rename) { copyFile(srcFile.getAbsolutePath(), destFile.getAbsolutePath()); deleteFile(srcFile.getAbsolutePath()); } } /** * copy file * * @param sourceFilePath * @param destFilePath * @return * @throws RuntimeException if an error occurs while operator FileOutputStream */ public static boolean copyFile(String sourceFilePath, String destFilePath) { InputStream inputStream = null; try { inputStream = new FileInputStream(sourceFilePath); } catch (FileNotFoundException e) { throw new RuntimeException("FileNotFoundException occurred. ", e); } return writeFile(destFilePath, inputStream); } /** * read file to string list, a element of list is a line * * @param filePath * @param charsetName The name of a supported {@link java.nio.charset.Charset </code>charset<code>} * @return if file not exist, return null, else return content of file * @throws RuntimeException if an error occurs while operator BufferedReader */ public static List<String> readFileToList(String filePath, String charsetName) { File file = new File(filePath); List<String> fileContent = new ArrayList<String>(); if (file == null || !file.isFile()) { return null; } BufferedReader reader = null; try { InputStreamReader is = new InputStreamReader(new FileInputStream(file), charsetName); reader = new BufferedReader(is); String line = null; while ((line = reader.readLine()) != null) { fileContent.add(line); } return fileContent; } catch (IOException e) { throw new RuntimeException("IOException occurred. ", e); } finally { IOUtils.close(reader); } } /** * get file name from path, not include suffix * * <pre> * getFileNameWithoutExtension(null) = null * getFileNameWithoutExtension("") = "" * getFileNameWithoutExtension(" ") = " " * getFileNameWithoutExtension("abc") = "abc" * getFileNameWithoutExtension("a.mp3") = "a" * getFileNameWithoutExtension("a.b.rmvb") = "a.b" * getFileNameWithoutExtension("c:\\") = "" * getFileNameWithoutExtension("c:\\a") = "a" * getFileNameWithoutExtension("c:\\a.b") = "a" * getFileNameWithoutExtension("c:a.txt\\a") = "a" * getFileNameWithoutExtension("/home/admin") = "admin" * getFileNameWithoutExtension("/home/admin/a.txt/b.mp3") = "b" * </pre> * * @param filePath * @return file name from path, not include suffix * @see */ public static String getFileNameWithoutExtension(String filePath) { if (StringUtils.isEmpty(filePath)) { return filePath; } int extenPosi = filePath.lastIndexOf(FILE_EXTENSION_SEPARATOR); int filePosi = filePath.lastIndexOf(File.separator); if (filePosi == -1) { return (extenPosi == -1 ? filePath : filePath.substring(0, extenPosi)); } if (extenPosi == -1) { return filePath.substring(filePosi + 1); } return (filePosi < extenPosi ? filePath.substring(filePosi + 1, extenPosi) : filePath.substring(filePosi + 1)); } /** * get file name from path, include suffix * * <pre> * getFileName(null) = null * getFileName("") = "" * getFileName(" ") = " " * getFileName("a.mp3") = "a.mp3" * getFileName("a.b.rmvb") = "a.b.rmvb" * getFileName("abc") = "abc" * getFileName("c:\\") = "" * getFileName("c:\\a") = "a" * getFileName("c:\\a.b") = "a.b" * getFileName("c:a.txt\\a") = "a" * getFileName("/home/admin") = "admin" * getFileName("/home/admin/a.txt/b.mp3") = "b.mp3" * </pre> * * @param filePath * @return file name from path, include suffix */ public static String getFileName(String filePath) { if (StringUtils.isEmpty(filePath)) { return filePath; } int filePosi = filePath.lastIndexOf(File.separator); return (filePosi == -1) ? filePath : filePath.substring(filePosi + 1); } /** * get folder name from path * * <pre> * getFolderName(null) = null * getFolderName("") = "" * getFolderName(" ") = "" * getFolderName("a.mp3") = "" * getFolderName("a.b.rmvb") = "" * getFolderName("abc") = "" * getFolderName("c:\\") = "c:" * getFolderName("c:\\a") = "c:" * getFolderName("c:\\a.b") = "c:" * getFolderName("c:a.txt\\a") = "c:a.txt" * getFolderName("c:a\\b\\c\\d.txt") = "c:a\\b\\c" * getFolderName("/home/admin") = "/home" * getFolderName("/home/admin/a.txt/b.mp3") = "/home/admin/a.txt" * </pre> * * @param filePath * @return */ public static String getFolderName(String filePath) { if (StringUtils.isEmpty(filePath)) { return filePath; } int filePosi = filePath.lastIndexOf(File.separator); return (filePosi == -1) ? "" : filePath.substring(0, filePosi); } /** * get suffix of file from path * * <pre> * getFileExtension(null) = "" * getFileExtension("") = "" * getFileExtension(" ") = " " * getFileExtension("a.mp3") = "mp3" * getFileExtension("a.b.rmvb") = "rmvb" * getFileExtension("abc") = "" * getFileExtension("c:\\") = "" * getFileExtension("c:\\a") = "" * getFileExtension("c:\\a.b") = "b" * getFileExtension("c:a.txt\\a") = "" * getFileExtension("/home/admin") = "" * getFileExtension("/home/admin/a.txt/b") = "" * getFileExtension("/home/admin/a.txt/b.mp3") = "mp3" * </pre> * * @param filePath * @return */ public static String getFileExtension(String filePath) { if (StringUtils.isBlank(filePath)) { return filePath; } int extenPosi = filePath.lastIndexOf(FILE_EXTENSION_SEPARATOR); int filePosi = filePath.lastIndexOf(File.separator); if (extenPosi == -1) { return ""; } return (filePosi >= extenPosi) ? "" : filePath.substring(extenPosi + 1); } /** * Creates the directory named by the trailing filename of this file, including the complete directory path required * to create this directory. <br/> * <br/> * <ul> * <strong>Attentions:</strong> * <li>makeDirs("C:\\Users\\Trinea") can only create users folder</li> * <li>makeFolder("C:\\Users\\Trinea\\") can create Trinea folder</li> * </ul> * * @param filePath * @return true if the necessary directories have been created or the target directory already exists, false one of * the directories can not be created. * <ul> * <li>if {@link FileUtils#getFolderName(String)} return null, return false</li> * <li>if target directory already exists, return true</li> * <li>return {@link java.io.File#makeFolder}</li> * </ul> */ public static boolean makeDirs(String filePath) { String folderName = getFolderName(filePath); if (StringUtils.isEmpty(folderName)) { return false; } File folder = new File(folderName); return (folder.exists() && folder.isDirectory()) ? true : folder.mkdirs(); } /** * @param filePath * @return * @see #makeDirs(String) */ public static boolean makeFolders(String filePath) { return makeDirs(filePath); } /** * Indicates if this file represents a file on the underlying file system. * * @param filePath * @return */ public static boolean isFileExist(String filePath) { if (StringUtils.isBlank(filePath)) { return false; } File file = new File(filePath); return (file.exists() && file.isFile()); } /** * Indicates if this file represents a directory on the underlying file system. * * @param directoryPath * @return */ public static boolean isFolderExist(String directoryPath) { if (StringUtils.isBlank(directoryPath)) { return false; } File dire = new File(directoryPath); return (dire.exists() && dire.isDirectory()); } /** * delete file or directory * <ul> * <li>if path is null or empty, return true</li> * <li>if path not exist, return true</li> * <li>if path exist, delete recursion. return true</li> * <ul> * * @param path * @return */ public static boolean deleteFile(String path) { if (StringUtils.isBlank(path)) { return true; } File file = new File(path); if (!file.exists()) { return true; } if (file.isFile()) { return file.delete(); } if (!file.isDirectory()) { return false; } for (File f : file.listFiles()) { if (f.isFile()) { f.delete(); } else if (f.isDirectory()) { deleteFile(f.getAbsolutePath()); } } return file.delete(); } /** * get file size * <ul> * <li>if path is null or empty, return -1</li> * <li>if path exist and it is a file, return file size, else return -1</li> * <ul> * * @param path * @return returns the length of this file in bytes. returns -1 if the file does not exist. */ public static long getFileSize(String path) { if (StringUtils.isBlank(path)) { return -1; } File file = new File(path); return (file.exists() && file.isFile() ? file.length() : -1); }}十三、assets和raw资源工具类 ResourceUtils.java
public class ResourceUtils { private ResourceUtils() { throw new AssertionError(); } /** * get an asset using ACCESS_STREAMING mode. This provides access to files that have been bundled with an * application as assets -- that is, files placed in to the "assets" directory. * * @param context * @param fileName The name of the asset to open. This name can be hierarchical. * @return */ public static String geFileFromAssets(Context context, String fileName) { if (context == null || StringUtils.isEmpty(fileName)) { return null; } StringBuilder s = new StringBuilder(""); try { InputStreamReader in = new InputStreamReader(context.getResources().getAssets().open(fileName)); BufferedReader br = new BufferedReader(in); String line; while ((line = br.readLine()) != null) { s.append(line); } return s.toString(); } catch (IOException e) { e.printStackTrace(); return null; } } /** * get content from a raw resource. This can only be used with resources whose value is the name of an asset files * -- that is, it can be used to open drawable, sound, and raw resources; it will fail on string and color * resources. * * @param context * @param resId The resource identifier to open, as generated by the appt tool. * @return */ public static String geFileFromRaw(Context context, int resId) { if (context == null) { return null; } StringBuilder s = new StringBuilder(); try { InputStreamReader in = new InputStreamReader(context.getResources().openRawResource(resId)); BufferedReader br = new BufferedReader(in); String line; while ((line = br.readLine()) != null) { s.append(line); } return s.toString(); } catch (IOException e) { e.printStackTrace(); return null; } } /** * same to {@link ResourceUtils#geFileFromAssets(Context, String)}, but return type is List<String> * * @param context * @param fileName * @return */ public static List<String> geFileToListFromAssets(Context context, String fileName) { if (context == null || StringUtils.isEmpty(fileName)) { return null; } List<String> fileContent = new ArrayList<String>(); try { InputStreamReader in = new InputStreamReader(context.getResources().getAssets().open(fileName)); BufferedReader br = new BufferedReader(in); String line; while ((line = br.readLine()) != null) { fileContent.add(line); } br.close(); return fileContent; } catch (IOException e) { e.printStackTrace(); return null; } } /** * same to {@link ResourceUtils#geFileFromRaw(Context, int)}, but return type is List<String> * * @param context * @param resId * @return */ public static List<String> geFileToListFromRaw(Context context, int resId) { if (context == null) { return null; } List<String> fileContent = new ArrayList<String>(); BufferedReader reader = null; try { InputStreamReader in = new InputStreamReader(context.getResources().openRawResource(resId)); reader = new BufferedReader(in); String line = null; while ((line = reader.readLine()) != null) { fileContent.add(line); } reader.close(); return fileContent; } catch (IOException e) { e.printStackTrace(); return null; } }}十四、单例工具类 SingletonUtils.java
public abstract class SingletonUtils<T> { private T instance; protected abstract T newInstance(); public final T getInstance() { if (instance == null) { synchronized (SingletonUtils.class) { if (instance == null) { instance = newInstance(); } } } return instance; }}十五、数据库工具类 SqliteUtils.java
public class SqliteUtils { private static volatile SqliteUtils instance; private DbHelper dbHelper; private SQLiteDatabase db; private SqliteUtils(Context context) { dbHelper = new DbHelper(context); db = dbHelper.getWritableDatabase(); } public static SqliteUtils getInstance(Context context) { if (instance == null) { synchronized (SqliteUtils.class) { if (instance == null) { instance = new SqliteUtils(context); } } } return instance; } public SQLiteDatabase getDb() { return db; }}更多工具类的设计可参考 GitHub项目：Trinea/android-common
十六、
参考文章：
- Android快速开发系列 10个常用工具类
- GitHub项目：Trinea/android-common
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- Android 框架：快速开发中Util常用工具类总结
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