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zmwxiaoming:
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struts2拦截器验证登陆状态 -
u012413283:
感谢楼主,同样的问题解决了
eclipse下安装m2e的maven插件报错的各类解决方案(含pom editor没装好的解决方案) -
javalucky:
你妹,想不吐槽都不行啊,eclipse 那来的maven4My ...
clipse加载maven工程提示pom.xml无法解析org.apache.maven.plugins:maven-resources-plugin: -
zhaoyh82:
感谢楼主
eclipse下安装m2e的maven插件报错的各类解决方案(含pom editor没装好的解决方案) -
hua2011:
按照楼主说的,还是没有出现pom editor编辑器,麻烦楼主 ...
eclipse下安装m2e的maven插件报错的各类解决方案(含pom editor没装好的解决方案)
本篇我们会介绍连接到网络中涉及的基本任务,监测的网络连接(包括连接更改),并给予用户控制应用程序的网络使用情况。还介绍了如何解析和使用XML数据。
这个类包含一个示例应用程序来说明如何执行常见的网络操作。您可以下载示例(在右边),并用它作为自己的应用程序源代码的可重用代码。本章的重点有三:
1.连接到网络
2.管理网络的使用
3.解析XML数据
一、连接到网络
在mainfest中声明权限,代码如下:
<uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
选择http客户端
大多数联网的Android应用程序使用HTTP来发送和接收数据。Android包括两个HTTP客户:HttpURLConnection HttpClient和Apache。都支持HTTPS,流媒体上传和下载,可配置的超时,IPv6,和连接池。我们建议使用HttpURLConnection目标应用程序。
检查网络连接
在你的应用程序尝试连接到网络,它应该检查是否一个网络连接可用使用getActiveNetworkInfo()和一个()。记住,这个装置可能范围的一个网络,或用户可能已经禁用wi - fi和移动数据访问。
public void myClickHandler(View view) { ... ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = connMgr.getActiveNetworkInfo(); if (networkInfo != null && networkInfo.isConnected()) { // fetch data } else { // display error } ... }
在单独线程中执行网络操作
网络操作可以包括不可预测的延迟。为了防止这种导致一个糟糕的用户体验,总是执行网络操作在一个单独的线程。
public class HttpExampleActivity extends Activity { private static final String DEBUG_TAG = "HttpExample"; private EditText urlText; private TextView textView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); urlText = (EditText) findViewById(R.id.myUrl); textView = (TextView) findViewById(R.id.myText); } // When user clicks button, calls AsyncTask. // Before attempting to fetch the URL, makes sure that there is a network connection. public void myClickHandler(View view) { // Gets the URL from the UI's text field. String stringUrl = urlText.getText().toString(); ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = connMgr.getActiveNetworkInfo(); if (networkInfo != null && networkInfo.isConnected()) { new DownloadWebpageText().execute(stringUrl); } else { textView.setText("No network connection available."); } } // Uses AsyncTask to create a task away from the main UI thread. This task takes a // URL string and uses it to create an HttpUrlConnection. Once the connection // has been established, the AsyncTask downloads the contents of the webpage as // an InputStream. Finally, the InputStream is converted into a string, which is // displayed in the UI by the AsyncTask's onPostExecute method. private class DownloadWebpageText extends AsyncTask { @Override protected String doInBackground(String... urls) { // params comes from the execute() call: params[0] is the url. try { return downloadUrl(urls[0]); } catch (IOException e) { return "Unable to retrieve web page. URL may be invalid."; } } // onPostExecute displays the results of the AsyncTask. @Override protected void onPostExecute(String result) { textView.setText(result); } } ... }
连接和下载数据
在你的线程执行您的网络交易,你可以使用HttpURLConnection来执行一个GET和下载数据。在您调用connect(),你可以得到一个InputStream的数据通过调用getInputStream()。
// Given a URL, establishes an HttpUrlConnection and retrieves // the web page content as a InputStream, which it returns as // a string. private String downloadUrl(String myurl) throws IOException { InputStream is = null; // Only display the first 500 characters of the retrieved // web page content. int len = 500; try { URL url = new URL(myurl); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setReadTimeout(10000 /* milliseconds */); conn.setConnectTimeout(15000 /* milliseconds */); conn.setRequestMethod("GET"); conn.setDoInput(true); // Starts the query conn.connect(); int response = conn.getResponseCode(); Log.d(DEBUG_TAG, "The response is: " + response); is = conn.getInputStream(); // Convert the InputStream into a string String contentAsString = readIt(is, len); return contentAsString; // Makes sure that the InputStream is closed after the app is // finished using it. } finally { if (is != null) { is.close(); } } }
getResponseCode()返回连接的状态码。这是一种有用的方式获得一些额外的信息的连接。一个200的状态代码表示成功。
转换InputStream到String
// Reads an InputStream and converts it to a String. public String readIt(InputStream stream, int len) throws IOException, UnsupportedEncodingException { Reader reader = null; reader = new InputStreamReader(stream, "UTF-8"); char[] buffer = new char[len]; reader.read(buffer); return new String(buffer); }
二、管理网络
检查设备的网络连接
一个设备可以有各种类型的网络连接。这节课的重点是使用wi - fi或手机或网络连接,这个代码片段测试网络连接wi - fi和移动。它确定这些网络接口是可用的或连接的(即网络连接是否存在,如果可以建立套接字和传递数据)
private static final String DEBUG_TAG = "NetworkStatusExample"; ... ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI); boolean isWifiConn = networkInfo.isConnected(); networkInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE); boolean isMobileConn = networkInfo.isConnected(); Log.d(DEBUG_TAG, "Wifi connected: " + isWifiConn); Log.d(DEBUG_TAG, "Mobile connected: " + isMobileConn);
管理网络的使用
您可以实现一个首选项活动,让用户明确控制应用程序的使用网络资源。例如: 1.你可能允许用户上传的视频只有当设备被连接到wi - fi网络。2.你可能会同步(或没有)根据特定标准如网络可用性、时间间隔,等等。
编写一个应用程序,支持网络访问和管理网络的使用,你的清单必须有正确的权限和意图过滤器。
在样例应用程序中,这个规定了SettingsActivity,将显示一个UI让用户知道何时可以进行下载操作。
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.android.networkusage" ...> <uses-sdk android:minSdkVersion="4" android:targetSdkVersion="14" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <application ...> ... <activity android:label="SettingsActivity" android:name=".SettingsActivity"> <intent-filter> <action android:name="android.intent.action.MANAGE_NETWORK_USAGE" /> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </activity> </application> </manifest>
public class SettingsActivity extends PreferenceActivity implements OnSharedPreferenceChangeListener { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Loads the XML preferences file addPreferencesFromResource(R.xml.preferences); } @Override protected void onResume() { super.onResume(); // Registers a listener whenever a key changes getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this); } @Override protected void onPause() { super.onPause(); // Unregisters the listener set in onResume(). // It's best practice to unregister listeners when your app isn't using them to cut down on // unnecessary system overhead. You do this in onPause(). getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this); } // When the user changes the preferences selection, // onSharedPreferenceChanged() restarts the main activity as a new // task. Sets the the refreshDisplay flag to "true" to indicate that // the main activity should update its display. // The main activity queries the PreferenceManager to get the latest settings. @Override public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) { // Sets refreshDisplay to true so that when the user returns to the main // activity, the display refreshes to reflect the new settings. NetworkActivity.refreshDisplay = true; } }
响应网络变动
如果有一个匹配发生在设置和设备的网络连接(例如,如果设置为“wi - fi”和设备有一个wi - fi连接)之间,应用程序下载提继续并刷新显示
public class NetworkActivity extends Activity { public static final String WIFI = "Wi-Fi"; public static final String ANY = "Any"; private static final String URL = "http://stackoverflow.com/feeds/tag?tagnames=android&sort=newest"; // Whether there is a Wi-Fi connection. private static boolean wifiConnected = false; // Whether there is a mobile connection. private static boolean mobileConnected = false; // Whether the display should be refreshed. public static boolean refreshDisplay = true; // The user's current network preference setting. public static String sPref = null; // The BroadcastReceiver that tracks network connectivity changes. private NetworkReceiver receiver = new NetworkReceiver(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Registers BroadcastReceiver to track network connection changes. IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION); receiver = new NetworkReceiver(); this.registerReceiver(receiver, filter); } @Override public void onDestroy() { super.onDestroy(); // Unregisters BroadcastReceiver when app is destroyed. if (receiver != null) { this.unregisterReceiver(receiver); } } // Refreshes the display if the network connection and the // pref settings allow it. @Override public void onStart () { super.onStart(); // Gets the user's network preference settings SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this); // Retrieves a string value for the preferences. The second parameter // is the default value to use if a preference value is not found. sPref = sharedPrefs.getString("listPref", "Wi-Fi"); updateConnectedFlags(); if(refreshDisplay){ loadPage(); } } // Checks the network connection and sets the wifiConnected and mobileConnected // variables accordingly. public void updateConnectedFlags() { ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo activeInfo = connMgr.getActiveNetworkInfo(); if (activeInfo != null && activeInfo.isConnected()) { wifiConnected = activeInfo.getType() == ConnectivityManager.TYPE_WIFI; mobileConnected = activeInfo.getType() == ConnectivityManager.TYPE_MOBILE; } else { wifiConnected = false; mobileConnected = false; } } // Uses AsyncTask subclass to download the XML feed from stackoverflow.com. public void loadPage() { if (((sPref.equals(ANY)) && (wifiConnected || mobileConnected)) || ((sPref.equals(WIFI)) && (wifiConnected))) { // AsyncTask subclass new DownloadXmlTask().execute(URL); } else { showErrorPage(); } } ... }
检测网络连接变化
public class NetworkReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { ConnectivityManager conn = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = conn.getActiveNetworkInfo(); // Checks the user prefs and the network connection. Based on the result, decides whether // to refresh the display or keep the current display. // If the userpref is Wi-Fi only, checks to see if the device has a Wi-Fi connection. if (WIFI.equals(sPref) && networkInfo != null && networkInfo.getType() == ConnectivityManager.TYPE_WIFI) { // If device has its Wi-Fi connection, sets refreshDisplay // to true. This causes the display to be refreshed when the user // returns to the app. refreshDisplay = true; Toast.makeText(context, R.string.wifi_connected, Toast.LENGTH_SHORT).show(); // If the setting is ANY network and there is a network connection // (which by process of elimination would be mobile), sets refreshDisplay to true. } else if (ANY.equals(sPref) && networkInfo != null) { refreshDisplay = true; // Otherwise, the app can't download content--either because there is no network // connection (mobile or Wi-Fi), or because the pref setting is WIFI, and there // is no Wi-Fi connection. // Sets refreshDisplay to false. } else { refreshDisplay = false; Toast.makeText(context, R.string.lost_connection, Toast.LENGTH_SHORT).show(); } }
三、解析xml
上传和解析XML数据是很常见的任务,网络连接应用程序。这一课解释了如何解析XML文档并使用他们的数据
选择转换器
我们建议XmlPullParser,这是一种高效且可维护的方式来解析XML在Android里。
分析需求
<?xml version="1.0" encoding="utf-8"?> <feed xmlns="http://www.w3.org/2005/Atom" xmlns:creativeCommons="http://backend.userland.com/creativeCommonsRssModule" ..."> <title type="text">newest questions tagged android - Stack Overflow</title> ... <entry> ... </entry> <entry> <id>http://stackoverflow.com/q/9439999</id> <re:rank scheme="http://stackoverflow.com">0</re:rank> <title type="text">Where is my data file?</title> <category scheme="http://stackoverflow.com/feeds/tag?tagnames=android&sort=newest/tags" term="android"/> <category scheme="http://stackoverflow.com/feeds/tag?tagnames=android&sort=newest/tags" term="file"/> <author> <name>cliff2310</name> <uri>http://stackoverflow.com/users/1128925</uri> </author> <link rel="alternate" href="http://stackoverflow.com/questions/9439999/where-is-my-data-file" /> <published>2012-02-25T00:30:54Z</published> <updated>2012-02-25T00:30:54Z</updated> <summary type="html"> <p>I have an Application that requires a data file...</p> </summary> </entry> <entry> ... </entry> ... </feed>
实例化转化器
public class StackOverflowXmlParser { // We don't use namespaces private static final String ns = null; public List parse(InputStream in) throws XmlPullParserException, IOException { try { XmlPullParser parser = Xml.newPullParser(); parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false); parser.setInput(in, null); parser.nextTag(); return readFeed(parser); } finally { in.close(); } } ... } 读取xml private List readFeed(XmlPullParser parser) throws XmlPullParserException, IOException { List entries = new ArrayList(); parser.require(XmlPullParser.START_TAG, ns, "feed"); while (parser.next() != XmlPullParser.END_TAG) { if (parser.getEventType() != XmlPullParser.START_TAG) { continue; } String name = parser.getName(); // Starts by looking for the entry tag if (name.equals("entry")) { entries.add(readEntry(parser)); } else { skip(parser); } } return entries; }
下面这个代码片段展示了如何解析器解析条目、标题、链接和总结:
public static class Entry { public final String title; public final String link; public final String summary; private Entry(String title, String summary, String link) { this.title = title; this.summary = summary; this.link = link; } } // Parses the contents of an entry. If it encounters a title, summary, or link tag, hands them off // to their respective "read" methods for processing. Otherwise, skips the tag. private Entry readEntry(XmlPullParser parser) throws XmlPullParserException, IOException { parser.require(XmlPullParser.START_TAG, ns, "entry"); String title = null; String summary = null; String link = null; while (parser.next() != XmlPullParser.END_TAG) { if (parser.getEventType() != XmlPullParser.START_TAG) { continue; } String name = parser.getName(); if (name.equals("title")) { title = readTitle(parser); } else if (name.equals("summary")) { summary = readSummary(parser); } else if (name.equals("link")) { link = readLink(parser); } else { skip(parser); } } return new Entry(title, summary, link); } // Processes title tags in the feed. private String readTitle(XmlPullParser parser) throws IOException, XmlPullParserException { parser.require(XmlPullParser.START_TAG, ns, "title"); String title = readText(parser); parser.require(XmlPullParser.END_TAG, ns, "title"); return title; } // Processes link tags in the feed. private String readLink(XmlPullParser parser) throws IOException, XmlPullParserException { String link = ""; parser.require(XmlPullParser.START_TAG, ns, "link"); String tag = parser.getName(); String relType = parser.getAttributeValue(null, "rel"); if (tag.equals("link")) { if (relType.equals("alternate")){ link = parser.getAttributeValue(null, "href"); parser.nextTag(); } } parser.require(XmlPullParser.END_TAG, ns, "link"); return link; } // Processes summary tags in the feed. private String readSummary(XmlPullParser parser) throws IOException, XmlPullParserException { parser.require(XmlPullParser.START_TAG, ns, "summary"); String summary = readText(parser); parser.require(XmlPullParser.END_TAG, ns, "summary"); return summary; } // For the tags title and summary, extracts their text values. private String readText(XmlPullParser parser) throws IOException, XmlPullParserException { String result = ""; if (parser.next() == XmlPullParser.TEXT) { result = parser.getText(); parser.nextTag(); } return result; } ... }
跳过无用的标签
private void skip(XmlPullParser parser) throws XmlPullParserException, IOException { if (parser.getEventType() != XmlPullParser.START_TAG) { throw new IllegalStateException(); } int depth = 1; while (depth != 0) { switch (parser.next()) { case XmlPullParser.END_TAG: depth--; break; case XmlPullParser.START_TAG: depth++; break; } } }
使用xml数据
public class NetworkActivity extends Activity { public static final String WIFI = "Wi-Fi"; public static final String ANY = "Any"; private static final String URL = "http://stackoverflow.com/feeds/tag?tagnames=android&sort=newest"; // Whether there is a Wi-Fi connection. private static boolean wifiConnected = false; // Whether there is a mobile connection. private static boolean mobileConnected = false; // Whether the display should be refreshed. public static boolean refreshDisplay = true; public static String sPref = null; ... // Uses AsyncTask to download the XML feed from stackoverflow.com. public void loadPage() { if((sPref.equals(ANY)) && (wifiConnected || mobileConnected)) { new DownloadXmlTask().execute(URL); } else if ((sPref.equals(WIFI)) && (wifiConnected)) { new DownloadXmlTask().execute(URL); } else { // show error } }
动态下载xml
// Implementation of AsyncTask used to download XML feed from stackoverflow.com. private class DownloadXmlTask extends AsyncTask<String, Void, String> { @Override protected String doInBackground(String... urls) { try { return loadXmlFromNetwork(urls[0]); } catch (IOException e) { return getResources().getString(R.string.connection_error); } catch (XmlPullParserException e) { return getResources().getString(R.string.xml_error); } } @Override protected void onPostExecute(String result) { setContentView(R.layout.main); // Displays the HTML string in the UI via a WebView WebView myWebView = (WebView) findViewById(R.id.webview); myWebView.loadData(result, "text/html", null); } }
加载xml
// Uploads XML from stackoverflow.com, parses it, and combines it with // HTML markup. Returns HTML string. private String loadXmlFromNetwork(String urlString) throws XmlPullParserException, IOException { InputStream stream = null; // Instantiate the parser StackOverflowXmlParser stackOverflowXmlParser = new StackOverflowXmlParser(); List<Entry> entries = null; String title = null; String url = null; String summary = null; Calendar rightNow = Calendar.getInstance(); DateFormat formatter = new SimpleDateFormat("MMM dd h:mmaa"); // Checks whether the user set the preference to include summary text SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this); boolean pref = sharedPrefs.getBoolean("summaryPref", false); StringBuilder htmlString = new StringBuilder(); htmlString.append("<h3>" + getResources().getString(R.string.page_title) + "</h3>"); htmlString.append("<em>" + getResources().getString(R.string.updated) + " " + formatter.format(rightNow.getTime()) + "</em>"); try { stream = downloadUrl(urlString); entries = stackOverflowXmlParser.parse(stream); // Makes sure that the InputStream is closed after the app is // finished using it. } finally { if (stream != null) { stream.close(); } } // StackOverflowXmlParser returns a List (called "entries") of Entry objects. // Each Entry object represents a single post in the XML feed. // This section processes the entries list to combine each entry with HTML markup. // Each entry is displayed in the UI as a link that optionally includes // a text summary. for (Entry entry : entries) { htmlString.append("<p><a href='"); htmlString.append(entry.link); htmlString.append("'>" + entry.title + "</a></p>"); // If the user set the preference to include summary text, // adds it to the display. if (pref) { htmlString.append(entry.summary); } } return htmlString.toString(); } // Given a string representation of a URL, sets up a connection and gets // an input stream. private InputStream downloadUrl(String urlString) throws IOException { URL url = new URL(urlString); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setReadTimeout(10000 /* milliseconds */); conn.setConnectTimeout(15000 /* milliseconds */); conn.setRequestMethod("GET"); conn.setDoInput(true); // Starts the query conn.connect(); InputStream stream = conn.getInputStream(); }
上面的片段代码为了帮助大家理解,这里还是老习惯,贴上项目的源代码,本来是有项目截图,运行效果图之类的图的,只是这篇文章太长了,再弄图片,就更占篇幅了,所以就只贴源码了,大家可以自己的运行起来看看,希望能从整体的架构和具体的代码细节上帮助到大家。
- NetworkUsage.rar (675 KB)
- 下载次数: 1
发表评论
-
android云同步
2012-10-23 16:23 1586通过互联网连接提供功能强大的API,Android框架 ... -
java.lang.RuntimeException: Unable to start activity ComponentInfo解决方案
2012-10-23 14:28 4476java.lang.RuntimeException: Un ... -
让你的app可以定位
2012-10-22 20:15 2783用户带和他们的移动设备与他们几乎无处不在。移动应用程序 ... -
android中完成分享功能(邮件或者短信方式)
2012-10-17 16:22 5095应上篇所说,我紧接着,便把前两篇的效果图中的最后一个按钮, ... -
android中使用PopupWindow实现弹出窗口菜单
2012-10-17 16:00 4021结合上篇android中使用ViewPager实现图片拖动, ... -
android调用webservice实现手机归属查询
2012-10-15 15:30 1502android中的webservice调用方式与java中差异 ... -
android中使用ViewPager实现图片左右拖动
2012-10-15 14:30 3517最近项目中做到一个帮助的功能,具体就是点击帮助按钮后,出现仿新 ...
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在Android开发中,网络操作是不可或缺的一部分,它使得应用程序能够获取远程数据,实现与服务器的交互。本知识点主要聚焦于如何在Android中进行网络操作的封装,以便开发者能更便捷地进行网络请求,提高开发效率。 ...
此外,Android有严格的网络访问策略,比如在主线程中直接进行网络操作会导致ANR(Application Not Responding)错误,因此网络操作通常应在工作线程或者IntentService中执行。为了提高用户体验,还可以使用AsyncTask...
在Android 4.0及以上版本中,为了保证用户界面的流畅性,网络操作通常不会在主线程中执行,而是通过子线程或者异步任务来处理。以下是对这个主题的详细阐述: 1. **网络访问基础** - Android系统出于性能和用户...
由于Android主线程不支持耗时操作,网络请求和图片加载通常在后台线程执行,然后通过Handler、AsyncTask或者使用RxJava等异步编程库来更新UI。 总的来说,这个“android实战 网络图片浏览器”项目涵盖了Android开发...
4. **网络请求的异步处理**:Android主线程不应直接执行网络操作,否则可能导致应用无响应。可以使用AsyncTask、Handler/Looper或Retrofit(一个基于OkHttp的高级网络库)进行异步处理。 5. **HTTPS与安全**:对于...
你可以创建一个继承自AsyncTask的类,重写doInBackground()方法来执行网络请求,然后在onPostExecute()方法中更新UI。 2. **使用Volley库**:Volley是Google推荐的网络请求库,它内部实现了线程池和请求队列,能...
2. 运行应用:启动待调试的应用,执行网络操作。 3. 监控调试:在调试助手中查看捕获的网络请求,分析问题。 4. 修改与重发:若需要,可修改请求参数并重新发送,观察不同参数下的服务器响应。 5. 结束调试:完成...
系统运行库层是Android的核心组成部分,它包含了各种库和运行环境,如Dalvik虚拟机(现在已被ART取代)用于执行Java代码,以及C/C++库,如SQLite用于数据库管理,OpenSSL用于网络安全,以及多媒体框架等。...
在Android开发中,掌握文件操作、网络通信、数据库管理和用户界面(UI)设计是至关重要的。以下是对这些关键知识点的详细说明: 1. **文件操作**: - Android中的文件操作主要包括读取和写入。`File`类是进行文件...
// 网络连接可用,执行网络操作 } else { // 网络未连接,提示用户或执行相应操作 } ``` 5. **监听网络变化** 若要实时监听网络状态的变化,可以注册一个`BroadcastReceiver`来接收网络状态改变的广播: ```...
罗列了android常用两种检测网络方法,在工作线程中定时执行检测操作
3. **AsyncTask**:Android提供的轻量级异步任务类,用于在后台线程执行网络操作,避免阻塞UI线程。但因为生命周期问题,不建议在大型项目中广泛使用。 4. **Volley库**:Google推出的网络请求库,提供了高效的缓存...
这不仅可以帮助开发者判断应用程序是否应该执行某些依赖于网络的操作(例如数据同步、下载资源等),还可以根据当前网络环境为用户提供更合适的提示或界面显示。 #### 1. 导入必要的包 首先,为了实现检测网络状态...