Imitation Box Horse - Positioning Acquisition (25)

Technology Stack
Appgallery Connect

Development Preparation
In the previous section, we implemented data querying and display for the address management page. Next, we will focus on address addition features, specifically map-based location selection. Before selecting a location on the map, we need to obtain the user's current location. After acquiring the coordinates and other information, we will display them on the corresponding map.

Functional Analysis
To implement location functionality:

Apply for location permissions in the application.
Check if location services are enabled each time the page loads. If not, prompt the user to enable them.
Request location permissions from the user. Upon approval, retrieve the current coordinates.

Code Implementation

1. Add Permissions in model.json5 json { "name": "ohos.permission.LOCATION", "reason": "$string:app_location", "usedScene": { "abilities": ["EntryAbility"], "when": "inuse" } }, { "name": "ohos.permission.APPROXIMATELY_LOCATION", "reason": "$string:app_reason_location", "usedScene": { "abilities": ["EntryAbility"], "when": "inuse" } }
2. Create Location Management Page typescript @State locationKey: boolean = false; @State addressSetting: boolean = false;

aboutToAppear(): void {
try {
const locationEnabled = geoLocationManager.isLocationEnabled();
this.addressSetting = locationEnabled;
} catch (err) {
console.error("errCode:" + err.code + ", message:" + err.message);
}
}

1. Prompt User to Enable Location
   typescript
   build() {
   Column() {
   Stack({ alignContent: Alignment.Bottom }) {
   Column() {
   // Content
   }
   .layoutWeight(1);

   if (this.addressSetting && !this.locationKey) {
   Row() {
   Text().width(40);
   Text("Location Disabled").fontColor(Color.Black);
   Text("Enable Location")
   .fontColor(Color.White)
   .backgroundColor(Color.Pink)
   .borderRadius(10)
   .padding(10)
   .onClick(() => {
   this.reqPermissionsFromUser(permissions);
   this.permissionController.open();
   });
   }
   .padding(10)
   .borderRadius(5)
   .margin({ bottom: 30 })
   .backgroundColor('#33000000')
   .justifyContent(FlexAlign.SpaceAround)
   .width('90%');
   }
   }
   .backgroundColor(Color.White)
   .height('100%')
   .width('100%');
   }
   }

2. Permission Request Dialog
   typescript
   @CustomDialog
   export default struct PermissionDialogWidget {
   @State titleText: string = '';
   @State contentText: string = '';
   controller: CustomDialogController;

build() {
Column() {
Text(this.titleText).margin({ top: 10 });
Text(this.contentText).margin({ top: 20, bottom: 10 });
}
.justifyContent(FlexAlign.Start)
.padding({ left: 20, right: 20 });
}
}

// Usage
permissionController: CustomDialogController = new CustomDialogController({
builder: PermissionDialogWidget({
titleText: "Permission Explanation",
contentText: 'Location permission is required for address selection. Once granted, this permission will be reused for address selection without re-requesting. Denying this permission will not affect other app functions.'
}),
alignment: DialogAlignment.Top
});

1. Execute Permission Request typescript reqPermissionsFromUser(permissions: Array): void { const context = getContext(this) as common.UIAbilityContext; const atManager = abilityAccessCtrl.createAtManager();

atManager.requestPermissionsFromUser(context, permissions).then((data) => {
const grantStatus: Array = data.authResults;

for (let i = 0; i < grantStatus.length; i++) {
  if (grantStatus[i] === 0) {
    this.locationKey = true;
    this.permissionController.close();

    const request: geoLocationManager.SingleLocationRequest = {
      'locatingPriority': geoLocationManager.LocatingPriority.PRIORITY_LOCATING_SPEED,
      'locatingTimeoutMs': 10000
    };

    try {
      geoLocationManager.getCurrentLocation(request).then((result) => {
        console.log('Current location: ' + JSON.stringify(result));

        const reverseGeocodeRequest: geoLocationManager.ReverseGeoCodeRequest = {
          "latitude": result.latitude, 
          "longitude": result.longitude, 
          "maxItems": 1
        };

        try {
          geoLocationManager.getAddressesFromLocation(reverseGeocodeRequest, (err, data) => {
            if (err) {
              console.error('getAddressesFromLocation error: ' + JSON.stringify(err));
            }
            if (data) {
              console.info('Address info: ' + JSON.stringify(data));
            }
          });
        } catch (err) {
          console.error("Reverse geocoding error: " + err.message);
        }
      }).catch((error) => {
        console.error('Location request error: ' + JSON.stringify(error));
      });
    } catch (err) {
      console.error("Location request exception: " + JSON.stringify(err));
    }
  } else {
    this.locationKey = false;
    this.permissionController.close();
    return;
  }
}

}).catch((err: Error) => {
console.error(Permission request failed: ${err.message});
});
}

This implementation achieves both the synchronous explanation through a custom dialog and the configuration of permission reasons in model.json5. You can choose the appropriate approach based on your needs.

The location coordinates are retrieved from the location request response, completing the location acquisition functionality.