方法一、引导用户修改

此方法使用系统提供的Action，跳转到系统界面，不涉及敏感权限，所有APP均可通用。方法如下：

  1. Intent intent = new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
  2. startActivityForResult(intent, 0);

方法二、代码修改

权限

这种方法需要修改SettingsProvider的值，需要使用的权限也很高：

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

但是，这个权限不是什么APP都能申请的，它的限定如下：

Permission is only granted to system apps. Permissions with the protection level signature, privileged or signatureOrSystem are only granted to system apps. If an app is a regular non-system app, it will never be able to use these permissions.

意思就是说，要使用这个权限，必须是系统APP（可以没有 platform 签名）。如果是系统APP，或者有platform权限，就继续往下看；否则，就放弃吧，苦海无涯回头是岸……

SettingsProvider

一般 SettingsProvider 的值，都能通过 android.provider.Settings 的内部类 Global、Secure、System 的各种 put 方法进行修改，修改也是即时生效的。比如修改WiFi开关状态：

  1. Settings.Global.putInt(
  2.         getContentResolver(),
  3.         Settings.Global.WIFI_ON,
  4.         isChecked ? 1 : 0       //1开，0关
  5. );

而位置信息的KEY值是：Settings.Secure.LOCATION_PROVIDERS_ALLOWED，具体说明如下：

  1. /**
  2.  * Comma-separated list of location providers that activities may access. Do not rely on
  3.  * this value being present in settings.db or on ContentObserver notifications on the
  4.  * corresponding Uri.
  5.  *
  6.  * @deprecated use {@link #LOCATION_MODE} and
  7.  * {@link LocationManager#MODE_CHANGED_ACTION} (or
  8.  * {@link LocationManager#PROVIDERS_CHANGED_ACTION})
  9.  */
  10. @Deprecated
  11. public static final String LOCATION_PROVIDERS_ALLOWED = "location_providers_allowed";
  13. /**
  14.  * The degree of location access enabled by the user.
  15.  * <p>
  16.  * When used with {@link #putInt(ContentResolver, String, int)}, must be one of {@link
  17.  * #LOCATION_MODE_HIGH_ACCURACY}, {@link #LOCATION_MODE_SENSORS_ONLY}, {@link
  18.  * #LOCATION_MODE_BATTERY_SAVING}, or {@link #LOCATION_MODE_OFF}. When used with {@link
  19.  * #getInt(ContentResolver, String)}, the caller must gracefully handle additional location
  20.  * modes that might be added in the future.
  21.  * <p>
  22.  * Note: do not rely on this value being present in settings.db or on ContentObserver
  23.  * notifications for the corresponding Uri. Use {@link LocationManager#MODE_CHANGED_ACTION}
  24.  * to receive changes in this value.
  25.  */
  26. public static final String LOCATION_MODE = "location_mode";

可以看到，LOCATION_PROVIDERS_ALLOWED 已经废弃（API19）了，取而代之的是 LOCATION_MODE，这个值的取值范围是如下这几个 int 值之一：

  1. /**
  2.  * Location access disabled.
  3.  */
  4. public static final int LOCATION_MODE_OFF = 0;
  5. /**
  6.  * Network Location Provider disabled, but GPS and other sensors enabled.
  7.  */
  8. public static final int LOCATION_MODE_SENSORS_ONLY = 1;
  9. /**
  10.  * Reduced power usage, such as limiting the number of GPS updates per hour. Requests
  11.  * with {@link android.location.Criteria#POWER_HIGH} may be downgraded to
  12.  * {@link android.location.Criteria#POWER_MEDIUM}.
  13.  */
  14. public static final int LOCATION_MODE_BATTERY_SAVING = 2;
  15. /**
  16.  * Best-effort location computation allowed.
  17.  */
  18. public static final int LOCATION_MODE_HIGH_ACCURACY = 3;

这些啥意思就不解释了，不懂的copy一下，出门右转百度翻译……

踩坑（M0，API22）

这里我的需求是，当检测到用户关闭位置信息开关时，自动将其重置为“网络定位”，即 BATTERY_SAVING 模式。

于是基于上面的分析，还有自己的经验积累，就有了一个方案：
对 LOCATION_MODE 的值进行监听，检测到变化后，判断是不是关闭操作；如果是，则重新设置为 BATTERY_SAVING 模式。样例代码如下：

  1. getContentResolver().registerContentObserver(
  2.         Settings.Secure.getUriFor(Settings.Secure.LOCATION_MODE),
  3.         false,
  4.         new ContentObserver(new Handler(Looper.getMainLooper())) {
  5.             @Override
  6.             public void onChange(boolean selfChange) {
  7.                 super.onChange(selfChange);
  9.                 int mode = Settings.Secure.getInt(getContentResolver(), Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_OFF);
  10.                 if (Settings.Secure.LOCATION_MODE_OFF == mode) {
  11.                     Settings.Secure.putInt(getContentResolver(), Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_BATTERY_SAVING);
  12.                 }
  13.             }
  14.         }
  15. );

看起来没毛病，结果却发现怎么也监听不到 LOCATION_MODE 的变化，WTF？？？
因为时间关系，就没有研究为什么监听不到了，后面有时间再细看一下。

因为我本职工作是做ROM定制开发的，在位置信息开关这个点上，经常有客需要默认开或者关，每次我们改的都是 xml 里面的字符串值，而这个修改方法到 O1 都是可行的。

字符串值说明： “”，关闭 “gps”，仅GPS传感器定位 “network”，仅网络定位，即省电模式 “gps,network”，高精度模式

这写字符串值是存储在LOCATION_PROVIDERS_ALLOWED里的，于是稍微调整了一下上面的代码：

  1. getContentResolver().registerContentObserver(
  2.         Settings.Secure.getUriFor(Settings.Secure.LOCATION_PROVIDERS_ALLOWED),
  3.         false,
  4.         new ContentObserver(new Handler(Looper.getMainLooper())) {
  5.             @Override
  6.             public void onChange(boolean selfChange) {
  7.             super.onChange(selfChange);
  9.             String mode = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
  10.             if (null == mode || "".equals(mode)) {
  11.                 Settings.Secure.putString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED, "network");
  12.             }
  13.         }
  14.     }
  15. );

本以为这样就可以了，结果却发现能监听到 LOCATION_PROVIDERS_ALLOWED 的变化，但是重置为“network”却不能成功……

不对呀，string 值就是这么 put 的呀！就在一脸懵逼的时候，仔细看了下 Settings.Secure 的方法列表，发现这么两个方法：
[app]Android 修改位置信息（GPS）开关状态 - 图1
好家伙，在这儿等着呢！

  1. @Deprecated
  2. public static final void setLocationProviderEnabled(ContentResolver cr,
  3.         String provider, boolean enabled) {
  4.     setLocationProviderEnabledForUser(cr, provider, enabled, UserHandle.myUserId());
  5. }
  7. @Deprecated
  8. public static final boolean setLocationProviderEnabledForUser(ContentResolver cr,
  9.         String provider, boolean enabled, int userId) {
  10.     synchronized (mLocationSettingsLock) {
  11.         // to ensure thread safety, we write the provider name with a '+' or '-'
  12.         // and let the SettingsProvider handle it rather than reading and modifying
  13.         // the list of enabled providers.
  14.         if (enabled) {
  15.             provider = "+" + provider;
  16.         } else {
  17.             provider = "-" + provider;
  18.         }
  19.         return putStringForUser(cr, Settings.Secure.LOCATION_PROVIDERS_ALLOWED, provider,
  20.                 userId);
  21.     }
  22. }

看到这就明白了，这货虽然看起来存的是"gps,network"的值，实际上是两个字段拼接的，每次通过 "+/- provider"去改变的。

因此，要想在用户关闭位置信息开关后，能重置为"network"，只需要将前面的代码稍作修改即可：

  1. String mode = Settings.Secure.getString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED);
  2. if (null == mode || "".equals(mode)) {
  3.     Settings.Secure.setLocationProviderEnabled(getContentResolver(), LocationManager.NETWORK_PROVIDER, true);
  4.     //或者用下面的方式
  5.     //Settings.Secure.putString(getContentResolver(), Settings.Secure.LOCATION_PROVIDERS_ALLOWED, "+network");
  6. }

补充：三方APP如何监听位置开关变化？

上面介绍的接听方法是系统APP适用的，三方APP没有权限这么做，但并不是没有办法，只不过实现不一样而已。
而方法在前面介绍源码时就已在注释信息中出现：

  1. /**
  2.  * The degree of location access enabled by the user.
  3.  * <p>
  4.  * When used with {@link #putInt(ContentResolver, String, int)}, must be one of {@link
  5.  * #LOCATION_MODE_HIGH_ACCURACY}, {@link #LOCATION_MODE_SENSORS_ONLY}, {@link
  6.  * #LOCATION_MODE_BATTERY_SAVING}, or {@link #LOCATION_MODE_OFF}. When used with {@link
  7.  * #getInt(ContentResolver, String)}, the caller must gracefully handle additional location
  8.  * modes that might be added in the future.
  9.  * <p>
  10.  * Note: do not rely on this value being present in settings.db or on ContentObserver
  11.  * notifications for the corresponding Uri. Use {@link LocationManager#MODE_CHANGED_ACTION}
  12.  * to receive changes in this value.
  13.  */
  14. public static final String LOCATION_MODE = "location_mode";

三方APP可以通过监听如下广播来监听开关变化：

  1. /**
  2.  * Broadcast intent action when {@link android.provider.Settings.Secure#LOCATION_MODE} changes.
  3.  * For use with the {@link android.provider.Settings.Secure#LOCATION_MODE} API.
  4.  * If you're interacting with {@link #isProviderEnabled(String)}, use
  5.  * {@link #PROVIDERS_CHANGED_ACTION} instead.
  6.  *
  7.  * In the future, there may be mode changes that do not result in
  8.  * {@link #PROVIDERS_CHANGED_ACTION} broadcasts.
  9.  */
  10. public static final String MODE_CHANGED_ACTION = "android.location.MODE_CHANGED";

示例如下：

  1. registerReceiver(
  2.         new BroadcastReceiver() {
  3.             @Override
  4.             public void onReceive(Context context, Intent intent) {
  5.                 LocationManager manager = (LocationManager) getSystemService(LOCATION_SERVICE);
  6.                 boolean isEnabled = manager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);//可以换成其它provider
  7.                 if (isEnabled) {
  8.                     //已开启
  9.                 }
  10.                 else {
  11.                     //已关闭，可引导用户打开
  12.                 }
  13.             }
  14.         },
  15.         new IntentFilter(LocationManager.PROVIDERS_CHANGED_ACTION)
  16. );