本帖最后由 ℡_莫忘ヽ悇溫╭ 于 2015-3-24 11:49 编辑 1、 精确获取屏幕尺寸(例如:3.5、4.0、5.0寸屏幕)
- public static double getScreenPhysicalSize(Activity ctx) {
- DisplayMetrics dm = new DisplayMetrics();
- ctx.getWindowManager().getDefaultDisplay().getMetrics(dm);
- double diagonalPixels = Math.sqrt(Math.pow(dm.widthPixels, 2) + Math.pow(dm.heightPixels, 2));
- return diagonalPixels / (160 * dm.density);
- }
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一般是7寸以上是平板 2、 判断是否是平板(官方用法)
- public static boolean isTablet(Context context) {
- return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_LARGE;
- }
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3、 文字根据状态更改颜色 android:textColor
- <selector xmlns:android="http://schemas.android.com/apk/res/android">
- <item android:color="#53c1bd" android:state_selected="true"/>
- <item android:color="#53c1bd" android:state_focused="true"/>
- <item android:color="#53c1bd" android:state_pressed="true"/>
- <item android:color="#777777"/>
- </selector>
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放在res/color/目录下 4、背景色根据状态更改颜色 android:backgroup
- <selector xmlns:android="http://schemas.android.com/apk/res/android">
-
- <item android:state_selected="true"><shape> <gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
- </shape></item>
- <item android:state_focused="true"><shape>
- <gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
- </shape></item>
- <item android:state_pressed="true"><shape>
- <gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" />
- </shape></item>
- <item><shape>
- <gradient android:angle="0" android:centerColor="#00ff00" android:endColor="00ff00" android:startColor="00ff00" />
- </shape></item>
-
- </selector>
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如果直接给背景色color会报错。 5、 启动APK的默认Activity
- public static void startApkActivity(final Context ctx, String packageName) {
- PackageManager pm = ctx.getPackageManager();
- PackageInfo pi;
- try {
- pi = pm.getPackageInfo(packageName, 0);
- Intent intent = new Intent(Intent.ACTION_MAIN, null);
- intent.addCategory(Intent.CATEGORY_LAUNCHER);
- intent.setPackage(pi.packageName);
-
- List<ResolveInfo> apps = pm.queryIntentActivities(intent, 0);
-
- ResolveInfo ri = apps.iterator().next();
- if (ri != null) {
- String className = ri.activityInfo.name;
- intent.setComponent(new ComponentName(packageName, className));
- ctx.startActivity(intent);
- }
- } catch (NameNotFoundException e) {
- Log.e("startActivity", e);
- }
- }
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7、计算字宽
- public static float GetTextWidth(String text, float Size) {
- TextPaint FontPaint = new TextPaint();
- FontPaint.setTextSize(Size);
- return FontPaint.measureText(text);
- }
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注意如果设置了textStyle,还需要进一步设置TextPaint。 8、获取应用程序下所有Activity
- public static ArrayList<String> getActivities(Context ctx) {
- ArrayList<String> result = new ArrayList<String>();
- Intent intent = new Intent(Intent.ACTION_MAIN, null);
- intent.setPackage(ctx.getPackageName());
- for (ResolveInfo info : ctx.getPackageManager().queryIntentActivities(intent, 0)) {
- result.add(info.activityInfo.name);
- }
- return result;
- }
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9、检测字符串中是否包含汉字
- public static boolean checkChinese(String sequence) {
- final String format = "[\\u4E00-\\u9FA5\\uF900-\\uFA2D]";
- boolean result = false;
- Pattern pattern = Pattern.compile(format);
- Matcher matcher = pattern.matcher(sequence);
- result = matcher.find();
- return result;
- }
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10、检测字符串中只能包含:中文、数字、下划线(_)、横线(-)
- public static boolean checkNickname(String sequence) {
- final String format = "[^\\u4E00-\\u9FA5\\uF900-\\uFA2D\\w-_]";
- Pattern pattern = Pattern.compile(format);
- Matcher matcher = pattern.matcher(sequence);
- return !matcher.find();
- }
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11、检查有没有应用程序来接受处理你发出的intent
- public static boolean isIntentAvailable(Context context, String action) {
- final PackageManager packageManager = context.getPackageManager();
- final Intent intent = new Intent(action);
- List<ResolveInfo> list = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
- return list.size() > 0;
- }
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12、使用TransitionDrawable实现渐变效果
- private void setImageBitmap(ImageView imageView, Bitmap bitmap) {
- // Use TransitionDrawable to fade in.
- final TransitionDrawable td = new TransitionDrawable(new Drawable[] { new ColorDrawable(android.R.color.transparent), new BitmapDrawable(mContext.getResources(), bitmap) });
- //noinspection deprecation
- imageView.setBackgroundDrawable(imageView.getDrawable());
- imageView.setImageDrawable(td);
- td.startTransition(200);
- }
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比使用AlphaAnimation效果要好,可避免出现闪烁问题。 13、扫描指定的文件 sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, uri)); 用途:从本软件新增、修改、删除图片、文件某一个文件(音频、视频)需要更新系统媒体库时使用,不必扫描整个SD卡 14、Dip转px
- public static int dipToPX(final Context ctx, float dip) {
- return (int)TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dip, ctx.getResources().getDisplayMetrics());
- }
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用途:难免在Activity代码中设置位置、大小等,本方法就很有用了! 15、获取已经安装APK的路径
- PackageManager pm = getPackageManager();
-
- for (ApplicationInfo app : pm.getInstalledApplications(0)) {
- Log.d("PackageList", "package: " + app.packageName + ", sourceDir: " + app.sourceDir);
- }
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输出如下:
- package: com.tmobile.thememanager, sourceDir: /system/app/ThemeManager.apk
- package: com.touchtype.swiftkey, sourceDir: /data/app/com.touchtype.swiftkey-1.apk
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- public static void putStringProcess(Context ctx, String key, String value) {
- SharedPreferences sharedPreferences = ctx.getSharedPreferences("preference_mu", Context.MODE_MULTI_PROCESS);
- Editor editor = sharedPreferences.edit();
- editor.putString(key, value);
- editor.commit();
- }
-
- public static String getStringProcess(Context ctx, String key, String defValue) {
- SharedPreferences sharedPreferences = ctx.getSharedPreferences("preference_mu", Context.MODE_MULTI_PROCESS);
- return sharedPreferences.getString(key, defValue);
- }
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相关文章: http://zengrong.net/post/1687.htm 17、泛型ArrayList转数组
- @SuppressWarnings("unchecked")
- public static <T> T[] toArray(Class<?> cls, ArrayList<T> items) {
- if (items == null || items.size() == 0) {
- return (T[]) Array.newInstance(cls, 0);
- }
- return items.toArray((T[]) Array.newInstance(cls, items.size()));
- }
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18、保存恢复ListView当前位置
- private void saveCurrentPosition() {
- if (mListView != null) {
- int position = mListView.getFirstVisiblePosition();
- View v = mListView.getChildAt(0);
- int top = (v == null) ? 0 : v.getTop();
- //保存position和top
- }
- }
-
- private void restorePosition() {
- if (mFolder != null && mListView != null) {
- int position = 0;//取出保存的数据
- int top = 0;//取出保存的数据
- mListView.setSelectionFromTop(position, top);
- }
- }
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可以保存在Preference中或者是数据库中,数据加载完后再设置。 19、调用 便携式热点和数据共享 设置
- public static Intent getHotspotSetting() {
- Intent intent = new Intent();
- intent.setAction(Intent.ACTION_MAIN);
- ComponentName com = new ComponentName("com.android.settings", "com.android.settings.TetherSettings");
- intent.setComponent(com);
- return intent;
- }
-
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20、格式化输出IP地址
- public static String getIp(Context ctx) {
- return Formatter.formatIpAddress((WifiManager) ctx.getSystemService(Context.WIFI_SERVICE).getConnectionInfo().getIpAddress());
- }
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21、文件夹排序(先文件夹排序,后文件排序)
- public static void sortFiles(File[] files) {
- Arrays.sort(files, new Comparator<File>() {
-
- @Override
- public int compare(File lhs, File rhs) {
- //返回负数表示o1 小于o2,返回0 表示o1和o2相等,返回正数表示o1大于o2。
- boolean l1 = lhs.isDirectory();
- boolean l2 = rhs.isDirectory();
- if (l1 && !l2)
- return -1;
- else if (!l1 && l2)
- return 1;
- else {
- return lhs.getName().compareTo(rhs.getName());
- }
- }
- });
- }
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22、发送不重复的通知(Notification)
- public static void sendNotification(Context context, String title,
- String message, Bundle extras) {
- Intent mIntent = new Intent(context, FragmentTabsActivity.class);
- mIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
- mIntent.putExtras(extras);
-
- int requestCode = (int) System.currentTimeMillis();
-
- PendingIntent mContentIntent = PendingIntent.getActivity(context,
- requestCode, mIntent, 0);
-
- Notification mNotification = new NotificationCompat.Builder(context)
- .setContentTitle(title).setSmallIcon(R.drawable.app_icon)
- .setContentIntent(mContentIntent).setContentText(message)
- .build();
- mNotification.flags |= Notification.FLAG_AUTO_CANCEL;
- mNotification.defaults = Notification.DEFAULT_ALL;
-
- NotificationManager mNotificationManager = (NotificationManager) context
- .getSystemService(Context.NOTIFICATION_SERVICE);
-
- mNotificationManager.notify(requestCode, mNotification);
- }
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关键点在这个requestCode,这里使用的是当前系统时间,巧妙的保证了每次都是一个新的Notification产生。 23、代码设置TextView的样式 使用过自定义Dialog可能马上会想到用如下代码: new TextView(this,null,R.style.text_style); 但你运行这代码你会发现毫无作用!正确用法: new TextView(new ContextThemeWrapper(this, R.style.text_style)) 24、ip地址转成8位十六进制串
- /** ip转16进制 */
- public static String ipToHex(String ips) {
- StringBuffer result = new StringBuffer();
- if (ips != null) {
- StringTokenizer st = new StringTokenizer(ips, ".");
- while (st.hasMoreTokens()) {
- String token = Integer.toHexString(Integer.parseInt(st.nextToken()));
- if (token.length() == 1)
- token = "0" + token;
- result.append(token);
- }
- }
- return result.toString();
- }
-
- /** 16进制转ip */
- public static String texToIp(String ips) {
- try {
- StringBuffer result = new StringBuffer();
- if (ips != null && ips.length() == 8) {
- for (int i = 0; i < 8; i += 2) {
- if (i != 0)
- result.append('.');
- result.append(Integer.parseInt(ips.substring(i, i + 2), 16));
- }
- }
- return result.toString();
- } catch (NumberFormatException ex) {
- Logger.e(ex);
- }
- return "";
- }
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ip:192.168.68.128 16 =>hex :c0a84480 25、WebView保留缩放功能但隐藏缩放控件
- mWebView.getSettings().setSupportZoom(true);
- mWebView.getSettings().setBuiltInZoomControls(true);
- if (DeviceUtils.hasHoneycomb())
- mWebView.getSettings().setDisplayZoomControls(false);
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注意:setDisplayZoomControls是在API Level 11中新增。 26、获取网络类型名称
- public static String getNetworkTypeName(Context context) {
- if (context != null) {
- ConnectivityManager connectMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
- if (connectMgr != null) {
- NetworkInfo info = connectMgr.getActiveNetworkInfo();
- if (info != null) {
- switch (info.getType()) {
- case ConnectivityManager.TYPE_WIFI:
- return "WIFI";
- case ConnectivityManager.TYPE_MOBILE:
- return getNetworkTypeName(info.getSubtype());
- }
- }
- }
- }
- return getNetworkTypeName(TelephonyManager.NETWORK_TYPE_UNKNOWN);
- }
-
- public static String getNetworkTypeName(int type) {
- switch (type) {
- case TelephonyManager.NETWORK_TYPE_GPRS:
- return "GPRS";
- case TelephonyManager.NETWORK_TYPE_EDGE:
- return "EDGE";
- case TelephonyManager.NETWORK_TYPE_UMTS:
- return "UMTS";
- case TelephonyManager.NETWORK_TYPE_HSDPA:
- return "HSDPA";
- case TelephonyManager.NETWORK_TYPE_HSUPA:
- return "HSUPA";
- case TelephonyManager.NETWORK_TYPE_HSPA:
- return "HSPA";
- case TelephonyManager.NETWORK_TYPE_CDMA:
- return "CDMA";
- case TelephonyManager.NETWORK_TYPE_EVDO_0:
- return "CDMA - EvDo rev. 0";
- case TelephonyManager.NETWORK_TYPE_EVDO_A:
- return "CDMA - EvDo rev. A";
- case TelephonyManager.NETWORK_TYPE_EVDO_B:
- return "CDMA - EvDo rev. B";
- case TelephonyManager.NETWORK_TYPE_1xRTT:
- return "CDMA - 1xRTT";
- case TelephonyManager.NETWORK_TYPE_LTE:
- return "LTE";
- case TelephonyManager.NETWORK_TYPE_EHRPD:
- return "CDMA - eHRPD";
- case TelephonyManager.NETWORK_TYPE_IDEN:
- return "iDEN";
- case TelephonyManager.NETWORK_TYPE_HSPAP:
- return "HSPA+";
- default:
- return "UNKNOWN";
- }
- }
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27、Android解压Zip包
- /**
- * 解压一个压缩文档 到指定位置
- *
- * @param zipFileString 压缩包的名字
- * @param outPathString 指定的路径
- * [url=home.php?mod=space&uid=2643633]@throws[/url] Exception
- */
- public static void UnZipFolder(String zipFileString, String outPathString) throws Exception {
- java.util.zip.ZipInputStream inZip = new java.util.zip.ZipInputStream(new java.io.FileInputStream(zipFileString));
- java.util.zip.ZipEntry zipEntry;
- String szName = "";
-
- while ((zipEntry = inZip.getNextEntry()) != null) {
- szName = zipEntry.getName();
-
- if (zipEntry.isDirectory()) {
-
- // get the folder name of the widget
- szName = szName.substring(0, szName.length() - 1);
- java.io.File folder = new java.io.File(outPathString + java.io.File.separator + szName);
- folder.mkdirs();
-
- } else {
-
- java.io.File file = new java.io.File(outPathString + java.io.File.separator + szName);
- file.createNewFile();
- // get the output stream of the file
- java.io.FileOutputStream out = new java.io.FileOutputStream(file);
- int len;
- byte[] buffer = new byte[1024];
- // read (len) bytes into buffer
- while ((len = inZip.read(buffer)) != -1) {
- // write (len) byte from buffer at the position 0
- out.write(buffer, 0, len);
- out.flush();
- }
- out.close();
- }
- }//end of while
-
- inZip.close();
-
- }//end of func
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28、从assets中读取文本和图片资源
- /** 从assets 文件夹中读取文本数据 */
- public static String getTextFromAssets(final Context context, String fileName) {
- String result = "";
- try {
- InputStream in = context.getResources().getAssets().open(fileName);
- // 获取文件的字节数
- int lenght = in.available();
- // 创建byte数组
- byte[] buffer = new byte[lenght];
- // 将文件中的数据读到byte数组中
- in.read(buffer);
- result = EncodingUtils.getString(buffer, "UTF-8");
- in.close();
- } catch (Exception e) {
- e.printStackTrace();
- }
- return result;
- }
-
- /** 从assets 文件夹中读取图片 */
- public static Drawable loadImageFromAsserts(final Context ctx, String fileName) {
- try {
- InputStream is = ctx.getResources().getAssets().open(fileName);
- return Drawable.createFromStream(is, null);
- } catch (IOException e) {
- if (e != null) {
- e.printStackTrace();
- }
- } catch (OutOfMemoryError e) {
- if (e != null) {
- e.printStackTrace();
- }
- } catch (Exception e) {
- if (e != null) {
- e.printStackTrace();
- }
- }
- return null;
- }
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29、展开、收起状态栏
- public static final void collapseStatusBar(Context ctx) {
- Object sbservice = ctx.getSystemService("statusbar");
- try {
- Class<?> statusBarManager = Class.forName("android.app.StatusBarManager");
- Method collapse;
- if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
- collapse = statusBarManager.getMethod("collapsePanels");
- } else {
- collapse = statusBarManager.getMethod("collapse");
- }
- collapse.invoke(sbservice);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
-
- public static final void expandStatusBar(Context ctx) {
- Object sbservice = ctx.getSystemService("statusbar");
- try {
- Class<?> statusBarManager = Class.forName("android.app.StatusBarManager");
- Method expand;
- if (Build.VERSION.SDK_INT >= 17) {
- expand = statusBarManager.getMethod("expandNotificationsPanel");
- } else {
- expand = statusBarManager.getMethod("expand");
- }
- expand.invoke(sbservice);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
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用途:可用于点击Notifacation之后收起状态栏 30、获取状态栏高度
- public static int getStatusBarHeight(Context context){
- Class<?> c = null;
- Object obj = null;
- Field field = null;
- int x = 0, statusBarHeight = 0;
- try {
- c = Class.forName("com.android.internal.R$dimen");
- obj = c.newInstance();
- field = c.getField("status_bar_height");
- x = Integer.parseInt(field.get(obj).toString());
- statusBarHeight = context.getResources().getDimensionPixelSize(x);
- } catch (Exception e1) {
- e1.printStackTrace();
- }
- return statusBarHeight;
- }
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31、ListView使用ViewHolder极简写法
- public static <T extends View> T getAdapterView(View convertView, int id) {
- SparseArray<View> viewHolder = (SparseArray<View>) convertView.getTag();
- if (viewHolder == null) {
- viewHolder = new SparseArray<View>();
- convertView.setTag(viewHolder);
- }
- View childView = viewHolder.get(id);
- if (childView == null) {
- childView = convertView.findViewById(id);
- viewHolder.put(id, childView);
- }
- return (T) childView;
- }
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用法:
- @Override
- public View getView(int position, View convertView, ViewGroup parent) {
- if (convertView == null) {
- convertView = LayoutInflater.from(getActivity()).inflate(R.layout.fragment_feed_item, parent, false);
- }
-
- ImageView thumnailView = getAdapterView(convertView, R.id.video_thumbnail);
- ImageView avatarView = getAdapterView(convertView, R.id.user_avatar);
- ImageView appIconView = getAdapterView(convertView, R.id.app_icon);
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用起来非常简练,将ViewHolder隐于无形。 32、设置Activity透明
- <style name="TransparentActivity" parent="AppBaseTheme">
- <item name="android:windowBackground">@android:color/transparent</item>
- <item name="android:colorBackgroundCacheHint">@null</item>
- <item name="android:windowIsTranslucent">true</item>
- <item name="android:windowNoTitle">true</item>
- <item name="android:windowContentOverlay">@null</item>
- </style>
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说明:AppBaseTheme一般是你application指定的android:theme是啥这里就是啥,否则Activity内部的空间风格可能不一致。 用途:用于模拟Dialog效果,比如再Service中没法用Dialog,就可以用Activity来模拟 33、代码切换全屏
- //切换到全屏
- getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
- getActivity().getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
-
- //切换到非全屏
- getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
- getWindow().addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
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注意:切换到全屏时,底部的虚拟按键仍然是显示的。次方法可多次调用用于切换 用途:播放器界面经常会用到 34、调用开发者选项中显示触摸位置功能 android.provider.Settings.System.putInt(getContentResolver(), "show_touches", 1); 设置1显示,设置0不显示。 35、获取设备上已安装并且可启动的应用列表
- Intent intent = new Intent(Intent.ACTION_MAIN);
- intent.addCategory(Intent.CATEGORY_LAUNCHER);
-
- List<ResolveInfo> activities = getPackageManager().queryIntentActivities(intent, 0)
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注意:使用getInstalledApplications会返回很多无法启动甚至没有图标的系统应用。ResolveInfo.activityInfo.applicationInfo也能取到你 想要的数据。
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