实用的Android代码片段集合（精）详解手机开发
2023-06-13 09:20:14 时间
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);
}
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;
}
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
放在res/color/目录下
4、背景色根据状态更改颜色 android:backgroup
1 selector xmlns:android="http://schemas.android.com/apk/res/android" 2 item android:state_selected="true" 3 shape 4 gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" / 5 /shape 6 /item 7 item android:state_focused="true" 8 shape 9 gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" / 10 /shape 11 /item 12 item android:state_pressed="true" 13 shape 14 gradient android:angle="0" android:centerColor="#00a59f" android:endColor="#00a59f" android:startColor="#00a59f" / 15 /shape 16 /item 17 item 18 shape 19 gradient android:angle="0" android:centerColor="#00ff00" android:endColor="00ff00" android:startColor="00ff00" / 20 /shape 21 /item 22 /selector
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);
}
7、计算字宽
public static float GetTextWidth(String text, float Size) {
TextPaint FontPaint = new TextPaint();
FontPaint.setTextSize(Size);
return FontPaint.measureText(text);
}
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;
}
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;
}
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();
}
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;
}
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);
}
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());
}
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);
}
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
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);
}
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()));
}
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);
}
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;
}
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());
}
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());
});
}
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);
}
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
1 /** ip转16进制 */
2 public static String ipToHex(String ips) {
3 StringBuffer result = new StringBuffer();
4 if (ips != null) {
5 StringTokenizer st = new StringTokenizer(ips, ".");
6 while (st.hasMoreTokens()) {
7 String token = Integer.toHexString(Integer.parseInt(st.nextToken()));
8 if (token.length() == 1)
9 token = "0" + token;
10 result.append(token);
11 }
12 }
13 return result.toString();
14 }
15 /** 16进制转ip */
16 public static String texToIp(String ips) {
17 try {
18 StringBuffer result = new StringBuffer();
19 if (ips != null ips.length() == 8) {
20 for (int i = 0; i i += 2) {
21 if (i != 0)
22 result.append(.);
23 result.append(Integer.parseInt(ips.substring(i, i + 2), 16));
24 }
25 }
26 return result.toString();
27 } catch (NumberFormatException ex) {
28 Logger.e(ex);
29 }
30 return "";
31 }
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);
注意：setDisplayZoomControls是在API Level 11中新增。
26、获取网络类型名称
1 public static String getNetworkTypeName(Context context) {
2 if (context != null) {
3 ConnectivityManager connectMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
4 if (connectMgr != null) {
5 NetworkInfo info = connectMgr.getActiveNetworkInfo();
6 if (info != null) {
7 switch (info.getType()) {
8 case ConnectivityManager.TYPE_WIFI:
9 return "WIFI";
10 case ConnectivityManager.TYPE_MOBILE:
11 return getNetworkTypeName(info.getSubtype());
12 }
13 }
14 }
15 }
16 return getNetworkTypeName(TelephonyManager.NETWORK_TYPE_UNKNOWN);
17 }
18 public static String getNetworkTypeName(int type) {
19 switch (type) {
20 case TelephonyManager.NETWORK_TYPE_GPRS:
21 return "GPRS";
22 case TelephonyManager.NETWORK_TYPE_EDGE:
23 return "EDGE";
24 case TelephonyManager.NETWORK_TYPE_UMTS:
25 return "UMTS";
26 case TelephonyManager.NETWORK_TYPE_HSDPA:
27 return "HSDPA";
28 case TelephonyManager.NETWORK_TYPE_HSUPA:
29 return "HSUPA";
30 case TelephonyManager.NETWORK_TYPE_HSPA:
31 return "HSPA";
32 case TelephonyManager.NETWORK_TYPE_CDMA:
33 return "CDMA";
34 case TelephonyManager.NETWORK_TYPE_EVDO_0:
35 return "CDMA - EvDo rev. 0";
36 case TelephonyManager.NETWORK_TYPE_EVDO_A:
37 return "CDMA - EvDo rev. A";
38 case TelephonyManager.NETWORK_TYPE_EVDO_B:
39 return "CDMA - EvDo rev. B";
40 case TelephonyManager.NETWORK_TYPE_1xRTT:
41 return "CDMA - 1xRTT";
42 case TelephonyManager.NETWORK_TYPE_LTE:
43 return "LTE";
44 case TelephonyManager.NETWORK_TYPE_EHRPD:
45 return "CDMA - eHRPD";
46 case TelephonyManager.NETWORK_TYPE_IDEN:
47 return "iDEN";
48 case TelephonyManager.NETWORK_TYPE_HSPAP:
49 return "HSPA+";
50 default:
51 return "UNKNOWN";
52 }
53 }
27、Android解压Zip包
1 /**
2 * 解压一个压缩文档 到指定位置
3 *
4 * @param zipFileString 压缩包的名字
5 * @param outPathString 指定的路径
6 * [url=home.php?mod=space uid=2643633]@throws[/url] Exception
7 */
8 public static void UnZipFolder(String zipFileString, String outPathString) throws Exception {
9 java.util.zip.ZipInputStream inZip = new java.util.zip.ZipInputStream(new java.io.FileInputStream(zipFileString));
10 java.util.zip.ZipEntry zipEntry;
11 String szName = "";
12 while ((zipEntry = inZip.getNextEntry()) != null) {
13 szName = zipEntry.getName();
14 if (zipEntry.isDirectory()) {
15 // get the folder name of the widget
16 szName = szName.substring(0, szName.length() - 1);
17 java.io.File folder = new java.io.File(outPathString + java.io.File.separator + szName);
18 folder.mkdirs();
19 } else {
20 java.io.File file = new java.io.File(outPathString + java.io.File.separator + szName);
21 file.createNewFile();
22 // get the output stream of the file
23 java.io.FileOutputStream out = new java.io.FileOutputStream(file);
24 int len;
25 byte[] buffer = new byte[1024];
26 // read (len) bytes into buffer
27 while ((len = inZip.read(buffer)) != -1) {
28 // write (len) byte from buffer at the position 0
29 out.write(buffer, 0, len);
30 out.flush();
31 }
32 out.close();
33 }
34 }//end of while
35 inZip.close();
36 }//end of func
28、从assets中读取文本和图片资源
1 /** 从assets 文件夹中读取文本数据 */
2 public static String getTextFromAssets(final Context context, String fileName) {
3 String result = "";
4 try {
5 InputStream in = context.getResources().getAssets().open(fileName);
6 // 获取文件的字节数
7 int lenght = in.available();
8 // 创建byte数组
9 byte[] buffer = new byte[lenght];
10 // 将文件中的数据读到byte数组中
11 in.read(buffer);
12 result = EncodingUtils.getString(buffer, "UTF-8");
13 in.close();
14 } catch (Exception e) {
15 e.printStackTrace();
16 }
17 return result;
18 }
20 /** 从assets 文件夹中读取图片 */
21 public static Drawable loadImageFromAsserts(final Context ctx, String fileName) {
22 try {
23 InputStream is = ctx.getResources().getAssets().open(fileName);
24 return Drawable.createFromStream(is, null);
25 } catch (IOException e) {
26 if (e != null) {
27 e.printStackTrace();
28 }
29 } catch (OutOfMemoryError e) {
30 if (e != null) {
31 e.printStackTrace();
32 }
33 } catch (Exception e) {
34 if (e != null) {
35 e.printStackTrace();
36 }
37 }
38 return null;
39 }
29、展开、收起状态栏
1 public static final void collapseStatusBar(Context ctx) {
2 Object sbservice = ctx.getSystemService("statusbar");
3 try {
4 Class ? statusBarManager = Class.forName("android.app.StatusBarManager");
5 Method collapse;
6 if (Build.VERSION.SDK_INT = Build.VERSION_CODES.JELLY_BEAN_MR1) {
7 collapse = statusBarManager.getMethod("collapsePanels");
8 } else {
9 collapse = statusBarManager.getMethod("collapse");
10 }
11 collapse.invoke(sbservice);
12 } catch (Exception e) {
13 e.printStackTrace();
14 }
15 }
16 public static final void expandStatusBar(Context ctx) {
17 Object sbservice = ctx.getSystemService("statusbar");
18 try {
19 Class ? statusBarManager = Class.forName("android.app.StatusBarManager");
20 Method expand;
21 if (Build.VERSION.SDK_INT = 17) {
22 expand = statusBarManager.getMethod("expandNotificationsPanel");
23 } else {
24 expand = statusBarManager.getMethod("expand");
25 }
26 expand.invoke(sbservice);
27 } catch (Exception e) {
28 e.printStackTrace();
29 }
30 }
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;
}
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;
}
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);
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
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);
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);
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。
6018.html
app程序应用开发手机开发无线开发移动端开发相关文章
- Android逆向第一步之开启root权限
- android中的加密算法,Android中加密算法[通俗易懂]
- android系统开机画面_Android开机画面
- android签名命令行,Android系统签名位置及命令
- strictmode android,Android 应用性能优化-StrictMode(严格模式)
- android 混淆规则作用,Android代码混淆详解
- android sdk根目录,Android SDK位置
- robotium android,Robotium 测试Android apk安装包
- android触摸屏事件,Android Touch事件分析
- Android修改字体_android设置字体样式
- Android 数据库加密 android-database-sqlcipher 开源版本编译过程
- 【Android 内存优化】libjpeg-turbo 函数库交叉编译 ( libjpeg-turbo 函数库下载 | libjpeg-turbo 编译文档 | 环境准备 | NASM 安装 )
- 【Android 安全】Android 应用 APK 加固总结 ( 加固原理 | 应用加固完整的实现方案 | 源码资源 )
- 【Android 逆向】Android 权限 ( Android 逆向中使用的 android.permission 权限 | Android 系统中的 Linux 用户权限 )
- 【Android 逆向】加壳的 Android 应用启动流程 | 使用反射替换 LoadedApk 中的类加载器流程
- 【ijkplayer】编译 Android 版本的 ijkplayer ③ ( 执行 compile-ffmpeg.sh clean 命令 | 下载并配置 android-ndk-r10e )
- 【ijkplayer】编译 Android 版本的 ijkplayer ⑥ ( 进入 ijkplayer-android/android 目录 | 执行 compile-ijk.sh 脚本完成编译 )
- 【Android UI】Paint Gradient 渐变渲染 ② ( SweepGradient 梯度渐变渲染 | 围绕中心点绘制扫描渐变的着色器 | 多渐变色构造函数 | 雷达扫描效果 )
- Android 路由设计最佳实践详解手机开发
- Android开发中遇到的问题(三)——eclipse创建android项目无法正常预览布局文件详解手机开发
- [android] 看博客学习Android常见的几种RuntimeException详解手机开发
- android Universal Image Loader for Android 说明文档 (1)详解手机开发
- Android Studio 导入项目 出现安装Error:Cause: failed to find target with hash string ‘android-23’ 等错误详解手机开发
- Android中的ProgressBar的android:indeterminate详解手机开发
- 细数Android系统那些DOS漏洞
- 安卓编年史（27）：Android 5.0 Lollipop——有史以来最重要的安卓版本
- android书架效果实现原理与代码