Android 判断网络状态，网络无连接时 打开网络设置对话框

在使用Android连接网络的时候，并不是每次都能连接到网络，在这个时候，我们最好是在程序启动的时候对网络的状态进行一下判断，如果没有网络则进行即时提醒用户进行设置。

要判断网络状态，首先需要有相应的权限，下面为权限代码：

即允许访问网络状态：

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

下面为判断代码：

/**
* 获取当前手机的网络状态
*
* @return
*/
private boolean isNetworkConnected() {

ConnectivityManager manager = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
NetworkInfo info = manager.getActiveNetworkInfo();
return (info != null && info.isConnected());

}若网络未连接，则进行提示，并可以进入设置网络界面

/**
* 提示网络状态不可用，并进行设置
*/
private void showSetNetworkDialog() {

AlertDialog.Builder builder = new Builder(this);
builder.setTitle("设置网络");
builder.setMessage("网络错误，请检查网络状态");
builder.setCancelable(false);
builder.setPositiveButton("设置网络", new OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
// Intent intent = new Intent();
// 类名一定要包含包名(这种显示意图不是很好，因为不同的系统可能包名，类名都不同，因此最好采用隐式意图进行跳转)
// intent.setClassName("com.android.phone",
// "com.android.phone.MiuiMobileNetworkSettings");
Intent intent = new Intent();
intent.setAction(Settings.ACTION_DATA_ROAMING_SETTINGS);
//startActivity(intent);
startActivityForResult(intent,0); // 如果在设置完成后需要再次进行操作，可以重写操作代码，在这里不再重写
finish();

}
});
builder.setNegativeButton("取消", new OnClickListener() {

public void onClick(DialogInterface dialog, int which) {
finish();
}
});
builder.create().show();

}

关于从Android应用程序跳转到各个设置页面

在android SDK文档中有这样一个类，android.provider.Settings类提供android系统各个页面的跳转常量：

使用实例例：

startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS))，即可跳到android手机网络设置页面。
 

如果要launch Mobile Networks Setting页面按如下方法：
Intent intent=new Intent(Settings.ACTION_DATA_ROAMING_SETTINGS);

ComponentName cName = new ComponentName(“com.android.phone”,”com.android.phone.Settings”);

intent.setComponent(cName);

startActivity(intent);

 

如果要进入Networks Operators页面按如下方法：
Intent intent = new Intent(Intent.ACTION_MAIN);

intent.setClassName(“com.android.phone”, “com.android.phone.NetworkSetting”);

startActivity(intent);

String	ACTION_ACCESSIBILITY_SETTINGS 辅助功能模块的显示设置。	Activity Action: Show settings for accessibility modules.
String	ACTION_ADD_ACCOUNT 显示屏幕上创建一个新帐户添加帐户。	Activity Action: Show add account screen for creating a new account.
String	ACTION_AIRPLANE_MODE_SETTINGS 显示设置，以允许进入/退出飞行模式。	Activity Action: Show settings to allow entering/exiting airplane mode.
String	ACTION_APN_SETTINGS 显示设置，以允许配 置的APN。	Activity Action: Show settings to allow configuration of APNs.
String	ACTION_APPLICATION_DETAILS_SETTINGS 有关特定应用程序的详细信息的显示屏幕。	Activity Action: Show screen of details about a particular application.
String	ACTION_APPLICATION_DEVELOPMENT_SETTINGS 显示设置，以允许应用程序开发相关的设置配置	Activity Action: Show settings to allow configuration of application development-related settings.
String	ACTION_APPLICATION_SETTINGS 显示设置，以允许应用程序相关的设置配置	Activity Action: Show settings to allow configuration of application-related settings.
String	ACTION_BLUETOOTH_SETTINGS 显示设置，以允许蓝牙配置	Activity Action: Show settings to allow configuration of Bluetooth.
String	ACTION_DATA_ROAMING_SETTINGS 选择of2G/3G显示设置	Activity Action: Show settings for selection of2G/3G.
String	ACTION_DATE_SETTINGS 显示日期和时间设置，以允许配 置	Activity Action: Show settings to allow configuration of date and time.
String	ACTION_DEVICE_INFO_SETTINGS 显示一般的设备信息设置（序列号，软件版本，电话号码，等）	Activity Action: Show general device information settings (serial number, software version, phone number, etc.).
String	ACTION_DISPLAY_SETTINGS 显示设置，以允许配 置显示	Activity Action: Show settings to allow configuration of display.
String	ACTION_INPUT_METHOD_SETTINGS 特别配置的输入方法，允许用户启用输入法的显示设置	Activity Action: Show settings to configure input methods, in particular allowing the user to enable input methods.
String	ACTION_INPUT_METHOD_SUBTYPE_SETTINGS 显示设置来启用/禁用输入法亚型	Activity Action: Show settings to enable/disable input method subtypes.
String	ACTION_INTERNAL_STORAGE_SETTINGS 内部存储的显示设置	Activity Action: Show settings for internal storage.
String	ACTION_LOCALE_SETTINGS 显示设置，以允许配 置的语言环境	Activity Action: Show settings to allow configuration of locale.
String	ACTION_LOCATION_SOURCE_SETTINGS 显示设置，以允许当前位置源的配置	Activity Action: Show settings to allow configuration of current location sources.
String	ACTION_MANAGE_ALL_APPLICATIONS_SETTINGS 显示设置来管理所有的应用程序	Activity Action: Show settings to manage all applications.
String	ACTION_MANAGE_APPLICATIONS_SETTINGS 显示设置来管理安装的应用程序	Activity Action: Show settings to manage installed applications.
String	ACTION_MEMORY_CARD_SETTINGS 显示设置为存储卡存储	Activity Action: Show settings for memory card storage.
String	ACTION_NETWORK_OPERATOR_SETTINGS 选择网络运营商的显示设置	Activity Action: Show settings for selecting the network operator.
String	ACTION_PRIVACY_SETTINGS 显示设置，以允许配 置隐私选项	Activity Action: Show settings to allow configuration of privacy options.
String	ACTION_QUICK_LAUNCH_SETTINGS 显示设置，以允许快速启动快捷键的配置	Activity Action: Show settings to allow configuration of quick launch shortcuts.
String	ACTION_SEARCH_SETTINGS 全局搜索显示设置	Activity Action: Show settings for global search.
String	ACTION_SECURITY_SETTINGS 显示设置，以允许配 置的安全性和位置隐私	Activity Action: Show settings to allow configuration of security and location privacy.
String	ACTION_SETTINGS 显示系统设置	Activity Action: Show system settings.
String	ACTION_SOUND_SETTINGS 显示设置，以允许配 置声音和音量	Activity Action: Show settings to allow configuration of sound and volume.
String	ACTION_SYNC_SETTINGS 显示设置，以允许配 置同步设置	Activity Action: Show settings to allow configuration of sync settings.
String	ACTION_USER_DICTIONARY_SETTINGS 显示设置来管理用户输入字典	Activity Action: Show settings to manage the user input dictionary.
String	ACTION_WIFI_IP_SETTINGS 显示设置，以允许配 置一个静态IP地址的Wi – Fi	Activity Action: Show settings to allow configuration of a static IP address for Wi-Fi.
String	ACTION_WIFI_SETTINGS 显示设置，以允许Wi – Fi配置	Activity Action: Show settings to allow configuration of Wi-Fi.
String	ACTION_WIRELESS_SETTINGS 显示设置，以允许配 置，如Wi – Fi，蓝牙和移动网络的无线控制	Activity Action: Show settings to allow configuration of wireless controls such as Wi-Fi, Bluetooth and Mobile networks.
String	AUTHORITY
String	EXTRA_AUTHORITIES 在推出活动的基础上给予的权力限制可选项。	Activity Extra: Limit available options in launched activity based on the given authority.
String	EXTRA_INPUT_METHOD_ID

参考：http://www.cnblogs.com/-cyb/articles/Android_forward_settings.html