Android 检测网络连接状态

http://blog.csdn.net/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

/**
 * 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;
}

	/**
	 * 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

/**
 * 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...");
    }
}

	/**
	 * 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：