Android 检测网络连接状态

http://blog.youkuaiyun.com/sunboy_2050/article/details/7896313

Android连接网络的时候，并不是每次都能连接到网络，因此在程序启动中需要对网络的状态进行判断，如果没有网络则提醒用户进行设置。

首先，要判断网络状态，需要有相应的权限，下面为权限代码（AndroidManifest.xml）：

  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
  <uses-permission android:name="android.permission.INTERNET"/>

然后，检测网络状态是否可用

[java] view plain copy print ?

1. /** 
2.  * 对网络连接状态进行判断 
3.  * @return  true, 可用； false， 不可用 
4.  */  
5. private boolean isOpenNetwork() {  
6.     ConnectivityManager connManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);  
7.     if(connManager.getActiveNetworkInfo() != null) {  
8.         return connManager.getActiveNetworkInfo().isAvailable();  
9.     }  
10.   
11.     return false;  
12. }  

	/**
	 * 对网络连接状态进行判断
	 * @return  true, 可用； false， 不可用
	 */
	private boolean isOpenNetwork() {
		ConnectivityManager connManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
		if(connManager.getActiveNetworkInfo() != null) {
			return connManager.getActiveNetworkInfo().isAvailable();
		}

		return false;
	}

最后，不可用则打开网络设置

[java] view plain copy print ?

1. /** 
2.  * 访问百度主页，网络不可用则需设置 
3.  */  
4. private void initMoreGames() {  
5.     String URL_MOREGAMES = "http://www.baidu.com";  
6.     mWebView = (WebView) findViewById(R.id.view_gamesort);  
7.   
8.     if (mWebView != null) {  
9.         mWebView.requestFocus();  
10.         WebSettings webSettings = mWebView.getSettings();  
11.         if (webSettings != null) {  
12.             webSettings.setJavaScriptEnabled(true);  
13.             webSettings.setCacheMode(MODE_PRIVATE);  
14.             webSettings.setDefaultTextEncodingName("utf-8");  
15.         }  
16.   
17.         // 判断网络是否可用   
18.         if(isOpenNetwork() == true) {  
19.             mWebView.loadUrl(URL_MOREGAMES);  
20.         } else {  
21.             AlertDialog.Builder builder = new AlertDialog.Builder(MoreGamesActivity.this);  
22.             builder.setTitle("没有可用的网络").setMessage("是否对网络进行设置?");  
23.               
24.             builder.setPositiveButton("是", new DialogInterface.OnClickListener() {  
25.                 @Override  
26.                 public void onClick(DialogInterface dialog, int which) {  
27.                     Intent intent = null;  
28.                       
29.                     try {  
30.                         String sdkVersion = android.os.Build.VERSION.SDK;  
31.                         if(Integer.valueOf(sdkVersion) > 10) {  
32.                             intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);  
33.                         }else {  
34.                             intent = new Intent();  
35.                             ComponentName comp = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings");  
36.                             intent.setComponent(comp);  
37.                             intent.setAction("android.intent.action.VIEW");  
38.                         }  
39.                         MoreGamesActivity.this.startActivity(intent);  
40.                     } catch (Exception e) {  
41.                         Log.w(TAG, "open network settings failed, please check...");  
42.                         e.printStackTrace();  
43.                     }  
44.                 }  
45.             }).setNegativeButton("否", new DialogInterface.OnClickListener() {  
46.                 @Override  
47.                 public void onClick(DialogInterface dialog, int which) {  
48.                     dialog.cancel();          
49.                     finish();  
50.                 }  
51.             }).show();  
52.         }  
53.     } else {  
54.         Log.w(TAG, "mWebView is null, please check...");  
55.     }  
56. }  

	/**
	 * 访问百度主页，网络不可用则需设置
	 */
	private void initMoreGames() {
		String URL_MOREGAMES = "http://www.baidu.com";
		mWebView = (WebView) findViewById(R.id.view_gamesort);

		if (mWebView != null) {
			mWebView.requestFocus();
			WebSettings webSettings = mWebView.getSettings();
			if (webSettings != null) {
				webSettings.setJavaScriptEnabled(true);
				webSettings.setCacheMode(MODE_PRIVATE);
				webSettings.setDefaultTextEncodingName("utf-8");
			}

			// 判断网络是否可用
			if(isOpenNetwork() == true) {
				mWebView.loadUrl(URL_MOREGAMES);
			} else {
				AlertDialog.Builder builder = new AlertDialog.Builder(MoreGamesActivity.this);
				builder.setTitle("没有可用的网络").setMessage("是否对网络进行设置?");
				
				builder.setPositiveButton("是", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						Intent intent = null;
						
						try {
							String sdkVersion = android.os.Build.VERSION.SDK;
							if(Integer.valueOf(sdkVersion) > 10) {
								intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
							}else {
								intent = new Intent();
								ComponentName comp = new ComponentName("com.android.settings", "com.android.settings.WirelessSettings");
								intent.setComponent(comp);
								intent.setAction("android.intent.action.VIEW");
							}
							MoreGamesActivity.this.startActivity(intent);
						} catch (Exception e) {
							Log.w(TAG, "open network settings failed, please check...");
							e.printStackTrace();
						}
					}
				}).setNegativeButton("否", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						dialog.cancel();		
						finish();
					}
				}).show();
			}
		} else {
			Log.w(TAG, "mWebView is null, please check...");
		}
	}

运行界面：