Android使用觀察者模式Observer實(shí)現(xiàn)網(wǎng)絡(luò)狀態(tài)監(jiān)聽

2019-10-22 18:10:27

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供稿：網(wǎng)友

在Android開發(fā)過程中，很多時(shí)候都會用到當(dāng)前網(wǎng)絡(luò)的狀態(tài)判斷以及網(wǎng)絡(luò)狀況發(fā)生變化的時(shí)候做出相應(yīng)的反應(yīng)，要想監(jiān)聽網(wǎng)絡(luò)狀態(tài)，用觀察者模式再合適不過了，廢話不多說，直接上代碼。

觀察者模式屬于面向?qū)ο蟮?3中設(shè)計(jì)模式之一，不了解的同學(xué)請自行Google

既然用觀察者模式，自然離不開觀察者模式里最重要的兩個(gè)類Subject和Ovserver了

Subjcet接口：

/** * Description: observer subject * author: Wang * date: 11/28/16 11:19 AM *  * Copyright©2016 by wang. All rights reserved. */public interface NetConnectionSubject {  /**   * 注冊觀察者   *   * @param observer   */  public void addNetObserver(NetConnectionObserver observer);  /**   * 移除觀察者   *   * @param observer   */  public void removeNetObserver(NetConnectionObserver observer);  /**   * 狀態(tài)更新通知   *   * @param type   */  public void notifyNetObserver(int type);}

Observer接口：

/** * Description: observer * author: Wang * date: 11/28/16 11:20 AM *  * Copyright©2016 by wang. All rights reserved. */public interface NetConnectionObserver {  /**   * 通知觀察者更改狀態(tài)   *   * @param type   */  public void updateNetStatus(int type);}

在Android里，最適合實(shí)現(xiàn)Subject類的，莫過于Application了，因?yàn)樗治ㄒ欢疑芷诰褪沁@個(gè)App的生命周期：

/** * Description: App's application should extend this class * author: Wang * date: 11/28/16 10:34 AM *  * Copyright©2016 by wang. All rights reserved. */public abstract class BaseApplication extends Application implements NetConnectionSubject {  protected static BaseApplication instance;  private int currentNetType = -1;  private List<NetConnectionObserver> observers = new ArrayList<>();  public static BaseApplication getInstance() {    return instance;  }  /**   * current net connection type   *   * @return   */  public int getCurrentNetType() {    return currentNetType;  }  /**   * current net connection status   *   * @return   */  public boolean isNetConnection() {    return currentNetType == NetWorkUtil.NET_NO_CONNECTION ? false : true;  }  @Override  public void onCreate() {    super.onCreate();    instance = this;    currentNetType = NetWorkUtil.getConnectionType(this);  }  @Override  public void addNetObserver(NetConnectionObserver observer) {    if (!observers.contains(observer)) {      observers.add(observer);    }  }  @Override  public void removeNetObserver(NetConnectionObserver observer) {    if (observers != null && observers.contains(observer)) {      observers.remove(observer);    }  }  @Override  public void notifyNetObserver(int type) {    /**     * 避免多次發(fā)送相同的網(wǎng)絡(luò)狀態(tài)     */    if (currentNetType == type) {      return;    } else {      currentNetType = type;      if (observers != null && observers.size() > 0) {        for (NetConnectionObserver observer : observers) {          observer.updateNetStatus(type);        }      }    }  }}

具體誰要實(shí)現(xiàn)Observer接口，就要看具體場景了，這里以Activity為栗子吧：

/** * Description: TODO * author: WangKunHui * date: 16/12/30 下午3:08 * <p> * Copyright©2016 by wang. All rights reserved. */public class TestActivity extends Activity implements NetConnectionObserver {  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    /**省略一些方法**/    BaseApplication.getInstance().addNetObserver(this);  }  @Override  public void updateNetStatus(int type) {    //當(dāng)監(jiān)聽網(wǎng)絡(luò)狀態(tài)發(fā)生變化 這里會及時(shí)的收到回饋  }  @Override  protected void onDestroy() {    super.onDestroy();    BaseApplication.getInstance().removeNetObserver(this);  }}

這里有個(gè)地方一定要注意：當(dāng)Activity銷毀的時(shí)候，一定要把這個(gè)觀察者從觀察者隊(duì)列里移除掉！否者會發(fā)生內(nèi)存泄漏

到這里，觀察者模式已經(jīng)寫完了，謝謝收看。

讀者：你是不是忘了點(diǎn)什么，說好的網(wǎng)絡(luò)監(jiān)聽呢？
我：Easy easy~ 剛剛只不過是中場休息

如果只有上面那么多的話，是不能監(jiān)聽網(wǎng)絡(luò)狀態(tài)的，想要監(jiān)聽網(wǎng)絡(luò)狀態(tài)的變化，還得靠我們的廣播接收者啊，有請：

/** * Description: 網(wǎng)絡(luò)連接狀態(tài)的監(jiān)聽 * author: Wang * date: 16/8/3 下午10:54 *  * Copyright©2016 by wang. All rights reserved. */public class NetConnectionReceiver extends BroadcastReceiver {  @Override  public void onReceive(Context context, Intent intent) {    if (intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION)) {      int connectionType = NetWorkUtil.getConnectionType(context);      /**       * 更改網(wǎng)絡(luò)狀態(tài)       */      if (BaseApplication.getInstance() != null) {        BaseApplication.getInstance().notifyNetObserver(connectionType);      }    }  }}

NetWorkUtil:

/** * @author Wang * @version 1.0.0 * @description 網(wǎng)絡(luò)操作工具類 * @create 2014-2-18 上午09:22:30 * @company  */public class NetWorkUtil {/**   * 無網(wǎng)絡(luò)鏈接   */  public static final int NET_NO_CONNECTION = 0;  /**   * wifi   */  public static final int NET_TYPE_WIFI = 1;  public static final int NET_TYPE_2G = 2;  public static final int NET_TYPE_3G = 3;  public static final int NET_TYPE_4G = 4;  /**   * 未知的網(wǎng)絡(luò)類型   */  public static final int NET_TYPE_UNKNOWN = 5; /**   * 獲取網(wǎng)絡(luò)類型   *   * @param context   * @return   */  public static int getConnectionType(Context context) {    int netType = NET_NO_CONNECTION;    NetworkInfo networkInfo = ((ConnectivityManager)    context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();    if (networkInfo == null) {      netType = NET_NO_CONNECTION;    } else {      if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {        netType = NET_TYPE_WIFI;      } else {        int networkType = networkInfo.getSubtype();        switch (networkType) {          case TelephonyManager.NETWORK_TYPE_GPRS:          case TelephonyManager.NETWORK_TYPE_EDGE:          case TelephonyManager.NETWORK_TYPE_CDMA:          case TelephonyManager.NETWORK_TYPE_1xRTT:          case TelephonyManager.NETWORK_TYPE_IDEN: //api<8 : replace by 11            netType = NET_TYPE_2G;            break;          case TelephonyManager.NETWORK_TYPE_UMTS:          case TelephonyManager.NETWORK_TYPE_EVDO_0:          case TelephonyManager.NETWORK_TYPE_EVDO_A:          case TelephonyManager.NETWORK_TYPE_HSDPA:          case TelephonyManager.NETWORK_TYPE_HSUPA:          case TelephonyManager.NETWORK_TYPE_HSPA:          case TelephonyManager.NETWORK_TYPE_EVDO_B: //api<9:replace by 14          case TelephonyManager.NETWORK_TYPE_EHRPD: //api<11:replace by 12          case TelephonyManager.NETWORK_TYPE_HSPAP: //api<13:replace by 15            netType = NET_TYPE_3G;            break;          case TelephonyManager.NETWORK_TYPE_LTE:  //api<11:replace by 13            netType = NET_TYPE_4G;            break;          default:            String subType = networkInfo.getSubtypeName();            if (subType.equalsIgnoreCase("TD-SCDMA") ||               subType.equalsIgnoreCase("WCDMA") ||              subType.equalsIgnoreCase("CDMA2000")) {              netType = NET_TYPE_3G;            } else {              netType = NET_TYPE_UNKNOWN;            }            break;        }      }    }    return netType;  }}

好了，到這里，標(biāo)題上所有的內(nèi)容已經(jīng)寫完了，最后，別忘了權(quán)限和注冊廣播接收者。

以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持VEVB武林網(wǎng)。

注：相關(guān)教程知識閱讀請移步到Android開發(fā)頻道。

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