1、 判斷是否為快速點選
/** 判斷是否是快速點選 */
private static long lastClickTime;
public static boolean isFastDoubleClick() {
long time = System.currentTimeMillis();
long timeD = time - lastClickTime;
if (0 < timeD && timeD < 500) {
return true;
}
lastClickTime = time;
return false;
} 2、日志工具類 Log.java
public class L
{
private L()
{
/* 不可被執行個體化 */
throw new UnsupportedOperationException("Cannot be instantiated!");
}
// 是否需要列印bug，可以在application的onCreate函數裡面初始化
public static boolean isDebug = true;
private static final String TAG = "DefaultTag";
// 下面四個是預設tag的函數
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);
}
// 下面是傳入自定義tag的函數
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);
}
} 3、DensityUtils
public class DensityUtils
{
private DensityUtils()
{
/* cannot be instantiated */
throw new UnsupportedOperationException("cannot be instantiated");
}
/**
* dp轉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轉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轉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轉sp
*
* @param fontScale
* @param pxVal
* @return
*/
public static float px2sp(Context context, float pxVal)
{
return (pxVal / context.getResources().getDisplayMetrics().scaledDensity);
}
} 4、SD卡相關輔助類 SDCardUtils.java
public class SDCardUtils
{
private SDCardUtils()
{
/* cannot be instantiated */
throw new UnsupportedOperationException("cannot be instantiated");
}
/**
* 判斷SDCard是否可用
*
* @return
*/
public static boolean isSDCardEnable()
{
return Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED);
}
/**
* 擷取SD卡路徑
*
* @return
*/
public static String getSDCardPath()
{
return Environment.getExternalStorageDirectory().getAbsolutePath()
+ File.separator;
}
/**
* 擷取SD卡的剩餘容量 機關byte
*
* @return
*/
public static long getSDCardAllSize()
{
if (isSDCardEnable())
{
StatFs stat = new StatFs(getSDCardPath());
// 擷取空閑的資料塊的數量
long availableBlocks = (long) stat.getAvailableBlocks() - 4;
// 擷取單個資料塊的大小（byte）
long freeBlocks = stat.getAvailableBlocks();
return freeBlocks * availableBlocks;
}
return 0;
}
/**
* 擷取指定路徑所在空間的剩餘可用容量位元組數，機關byte
*
* @param filePath
* @return 容量位元組 SDCard可用空間，内部存儲可用空間
*/
public static long getFreeBytes(String filePath)
{
// 如果是sd卡的下的路徑，則擷取sd卡可用容量
if (filePath.startsWith(getSDCardPath()))
{
filePath = getSDCardPath();
} else
{// 如果是内部存儲的路徑，則擷取記憶體存儲的可用容量
filePath = Environment.getDataDirectory().getAbsolutePath();
}
StatFs stat = new StatFs(filePath);
long availableBlocks = (long) stat.getAvailableBlocks() - 4;
return stat.getBlockSize() * availableBlocks;
}
/**
* 擷取系統存儲路徑
*
* @return
*/
public static String getRootDirectoryPath()
{
return Environment.getRootDirectory().getAbsolutePath();
}
} 5、螢幕相關輔助類 ScreenUtils.java
public class ScreenUtils
{
private ScreenUtils()
{
/* cannot be instantiated */
throw new UnsupportedOperationException("cannot be instantiated");
}
/**
* 獲得螢幕高度
*
* @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;
}
/**
* 獲得螢幕寬度
*
* @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;
}
/**
* 獲得狀态欄的高度
*
* @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;
}
/**
* 擷取目前螢幕截圖，包含狀态欄
*
* @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;
}
/**
* 擷取目前螢幕截圖，不包含狀态欄
*
* @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;
}
} 6、檔案工具類 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);
}
} 7、assets和raw資源工具類 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;
}
}
} 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;
}
} ![Java小案例——随機數猜測随機數猜測[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)