Android GPS 打开流程

Android P平台 ：http://androidxref.com/9.0.0_r3/

1. Settings 界面打开，流程大致如下：

http://androidxref.com/9.0.0_r3/xref/packages/apps/Settings/src/com/android/settings/location/LocationSwitchBarController.java#setLocationEnabled

http://androidxref.com/9.0.0_r3/xref/packages/apps/Settings/src/com/android/settings/location/LocationEnabler.java#setLocationEnabled

    void setLocationEnabled(boolean enabled) {
           // 从数据库拿值，看下此刻的 LOCATION_MODE
        final int currentMode = Settings.Secure.getInt(mContext.getContentResolver(),
            Settings.Secure.LOCATION_MODE, Settings.Secure.LOCATION_MODE_OFF);

        if (isRestricted()) {   ---> 当前用户是否有权限
            // Location toggling disabled by user restriction. Read the current location mode to
            // update the location master switch.
            if (Log.isLoggable(TAG, Log.INFO)) {
                Log.i(TAG, "Restricted user, not setting location mode");
            }
            if (mListener != null) {
                mListener.onLocationModeChanged(currentMode, true);
            }
            return;
        }
           // 主要看下这个地方
        updateLocationEnabled(mContext, enabled, UserHandle.myUserId(),
                Settings.Secure.LOCATION_CHANGER_SYSTEM_SETTINGS);
        refreshLocationMode();
    }