小编Vip*_*bey的帖子

class BottomNavigationDrawerFragment: BottomSheetDialogFragment(), 
   NavigationView.OnNavigationItemSelectedListener {

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return inflater.inflate(R.layout.fragment_bottomsheet, container, false)
    }

    override fun onNavigationItemSelected(item : MenuItem): Boolean {
        // Bottom Navigation Drawer menu item clicks
        when (item.itemId) {
            R.id.nav1 -> context!!.toast("oneeeeee")
            R.id.nav2 -> context!!.toast("twoooooo")
            R.id.nav3 -> context!!.toast("threeeee")

            return true
        }
        // Add code here to update the UI based on the item selected
        // For example, swap
    }
    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)

        navigation_view.setNavigationItemSelectedListener(this)

        // Add code here to update …

def plot_decision_regions(X, y, classifier, resolution=0.02):
    # setup marker generator and color map
    markers = ('s', 'x', 'o', '^', 'v')
    colors = ('red', 'blue', 'lightgreen', 'gray', 'cyan')
    cmap = ListedColormap(colors[:len(np.unique(y))])
    # plot the decision surface
    x1_min, x1_max = X[:, 0].min() - 1, X[:, 0].max() + 1
    x2_min, x2_max = X[:, 1].min() - 1, X[:, 1].max() + 1
    xx1, xx2 = np.meshgrid(np.arange(x1_min, x1_max, resolution),
        np.arange(x2_min, x2_max, resolution))
    Z = classifier.predict(np.array([xx1.ravel(), xx2.ravel()]).T)
    Z = Z.reshape(xx1.shape)
    plt.contourf(xx1, xx2, Z, alpha=0.4, cmap=cmap)
    plt.xlim(xx1.min(), xx1.max())
    plt.ylim(xx2.min(), …

我正在制作一个使用 gps 访问用户位置的应用程序。这就是为什么我在 AndroidManifest.xml 中添加了以下几行

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

下面是我获取用户位置的函数

componentWillMount(){
    navigator.geolocation.getCurrentPosition(
      position => {

        this.setState({
          latitude: position.coords.latitude,
          longitude: position.coords.longitude,

        });
      },
      error => Alert.alert(error.message),
      { enableHighAccuracy: true, timeout: 20000, maximumAge: 1000 }
    );

  }

但这会产生错误，即应用程序无权访问位置，我需要声明

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

在清单文件中。我尝试了很多方法并找到了一个解决方案，即要求运行时许可。所以我还在我的代码中添加了以下几行

try {
      const granted =  PermissionsAndroid.request(
        PermissionsAndroid.PERMISSIONS.ACCESS_FINE_LOCATION,
        {
          'title': 'Location Permission',
          'message': 'This app needs access to your location',
        }
      )
      if (granted === PermissionsAndroid.RESULTS.GRANTED) {
        console.log("You can use the location")
      } else {
        console.log("Location permission denied")
      }
    } …