التعامل مع أحداث الماوس

يمكنك السماح لميزات البيانات بالاستجابة إلى حدثَي mousemove وclick واستخدامهما لتغيير مظهر الميزة استنادًا إلى تفاعل المستخدم.

تفعيل أحداث طبقات مجموعة البيانات

اتّبِع الخطوات التالية لتفعيل الأحداث على طبقة مجموعة بيانات:

  1. يمكنك تسجيل طبقة مجموعة بيانات لإشعارات الأحداث من خلال استدعاء الدالة addListener() على طبقة مجموعة البيانات لكل حدث تريد تسجيله. في هذا المثال، تحصل الخريطة أيضًا على مستمع.

    TypeScript

    datasetLayer = map.getDatasetFeatureLayer(datasetId);
    datasetLayer.style = applyStyle;
    
    datasetLayer.addListener('click', handleClick);
    datasetLayer.addListener('mousemove', handleMouseMove);
    
    // Map event listener.
    map.addListener('mousemove', () => {
      // If the map gets a mousemove, that means there are no feature layers
      // with listeners registered under the mouse, so we clear the last
      // interacted feature ids.
      if (lastInteractedFeatureIds?.length) {
        lastInteractedFeatureIds = [];
        datasetLayer.style = applyStyle;
      }
    });

    JavaScript

    datasetLayer = map.getDatasetFeatureLayer(datasetId);
    datasetLayer.style = applyStyle;
    datasetLayer.addListener("click", handleClick);
    datasetLayer.addListener("mousemove", handleMouseMove);
    // Map event listener.
    map.addListener("mousemove", () => {
      // If the map gets a mousemove, that means there are no feature layers
      // with listeners registered under the mouse, so we clear the last
      // interacted feature ids.
      if (lastInteractedFeatureIds?.length) {
        lastInteractedFeatureIds = [];
        datasetLayer.style = applyStyle;
      }
    });
    

  2. أضِف رمز معالج الأحداث لتصميم الميزة المحدّدة استنادًا إلى نوع التفاعل.

    TypeScript

    // Note, 'globalid' is an attribute in this Dataset.
    function handleClick(/* MouseEvent */ e) {
      if (e.features) {
        lastClickedFeatureIds =
            e.features.map((f) => f.datasetAttributes['globalid']);
      }
      //@ts-ignore
      datasetLayer.style = applyStyle;
    }
    
    function handleMouseMove(/* MouseEvent */ e) {
      if (e.features) {
        lastInteractedFeatureIds =
            e.features.map((f) => f.datasetAttributes['globalid']);
      }
      //@ts-ignore
      datasetLayer.style = applyStyle;
    }

    JavaScript

    // Note, 'globalid' is an attribute in this Dataset.
    function handleClick(/* MouseEvent */ e) {
      if (e.features) {
        lastClickedFeatureIds = e.features.map(
          (f) => f.datasetAttributes["globalid"],
        );
      }
    
      //@ts-ignore
      datasetLayer.style = applyStyle;
    }
    
    function handleMouseMove(/* MouseEvent */ e) {
      if (e.features) {
        lastInteractedFeatureIds = e.features.map(
          (f) => f.datasetAttributes["globalid"],
        );
      }
    
      //@ts-ignore
      datasetLayer.style = applyStyle;
    }
    

  3. استخدِم دالة نمط الميزة لتطبيق الأنماط. تطبق دالة نمط الميزة الموضحة هنا النمط بشكل مشروط بناءً على نوع التفاعل. يتم هنا تحديد ثلاثة أنماط: أحدها لجعل الحد بخط غامق على mousemove، ونمط لتغيير الخلفية في click، ونمط تلقائي.

    TypeScript

    const styleDefault = {
      strokeColor: 'green',
      strokeWeight: 2.0,
      strokeOpacity: 1.0,
      fillColor: 'green',
      fillOpacity: 0.3,
    };
    
    const styleClicked = {
      ...styleDefault,
      strokeColor: 'blue',
      fillColor: 'blue',
      fillOpacity: 0.5,
    };
    
    const styleMouseMove = {
       ...styleDefault,
      strokeWeight: 4.0
    };
    
    function applyStyle(/* FeatureStyleFunctionOptions */ params) {
      const datasetFeature = params.feature;
      // Note, 'globalid' is an attribute in this dataset.
      //@ts-ignore
      if (lastClickedFeatureIds.includes(datasetFeature.datasetAttributes['globalid'])) {
        return styleClicked;
      }
      //@ts-ignore
      if (lastInteractedFeatureIds.includes(datasetFeature.datasetAttributes['globalid'])) {
        return styleMouseMove;
      }
      return styleDefault;
    }

    JavaScript

    const styleDefault = {
      strokeColor: "green",
      strokeWeight: 2.0,
      strokeOpacity: 1.0,
      fillColor: "green",
      fillOpacity: 0.3,
    };
    const styleClicked = {
      ...styleDefault,
      strokeColor: "blue",
      fillColor: "blue",
      fillOpacity: 0.5,
    };
    const styleMouseMove = {
      ...styleDefault,
      strokeWeight: 4.0,
    };
    
    function applyStyle(/* FeatureStyleFunctionOptions */ params) {
      const datasetFeature = params.feature;
    
      // Note, 'globalid' is an attribute in this dataset.
      //@ts-ignore
      if (
        lastClickedFeatureIds.includes(datasetFeature.datasetAttributes["globalid"])
      ) {
        return styleClicked;
      }
    
      //@ts-ignore
      if (
        lastInteractedFeatureIds.includes(
          datasetFeature.datasetAttributes["globalid"],
        )
      ) {
        return styleMouseMove;
      }
      return styleDefault;
    }
    

إكمال نموذج الرمز

TypeScript

let map: google.maps.Map;
let lastInteractedFeatureIds = [];
let lastClickedFeatureIds = [];
let datasetLayer;

// Note, 'globalid' is an attribute in this Dataset.
function handleClick(/* MouseEvent */ e) {
  if (e.features) {
    lastClickedFeatureIds =
        e.features.map((f) => f.datasetAttributes['globalid']);
  }
  //@ts-ignore
  datasetLayer.style = applyStyle;
}

function handleMouseMove(/* MouseEvent */ e) {
  if (e.features) {
    lastInteractedFeatureIds =
        e.features.map((f) => f.datasetAttributes['globalid']);
  }
  //@ts-ignore
  datasetLayer.style = applyStyle;
}

async function initMap() {
  // Request needed libraries.
  const { Map } = await google.maps.importLibrary('maps') as google.maps.MapsLibrary;

  const position = {lat: 40.780101, lng: -73.967780};
  map = new Map(document.getElementById('map') as HTMLElement, {
    zoom: 13,
    center: position,
    mapId: 'b98e588c46685dd7',
    mapTypeControl: false,
  });

  // Dataset ID for NYC park data.
  const datasetId = '6fe13aa9-b900-45e7-b636-3236672c3f4f';

  //@ts-ignore
  datasetLayer = map.getDatasetFeatureLayer(datasetId);
  datasetLayer.style = applyStyle;

  datasetLayer.addListener('click', handleClick);
  datasetLayer.addListener('mousemove', handleMouseMove);

  // Map event listener.
  map.addListener('mousemove', () => {
    // If the map gets a mousemove, that means there are no feature layers
    // with listeners registered under the mouse, so we clear the last
    // interacted feature ids.
    if (lastInteractedFeatureIds?.length) {
      lastInteractedFeatureIds = [];
      datasetLayer.style = applyStyle;
    }
  });
  const attributionDiv = document.createElement('div');
  const attributionControl = createAttribution(map);

  attributionDiv.appendChild(attributionControl);
  map.controls[google.maps.ControlPosition.LEFT_BOTTOM].push(attributionDiv);
}

const styleDefault = {
  strokeColor: 'green',
  strokeWeight: 2.0,
  strokeOpacity: 1.0,
  fillColor: 'green',
  fillOpacity: 0.3,
};

const styleClicked = {
  ...styleDefault,
  strokeColor: 'blue',
  fillColor: 'blue',
  fillOpacity: 0.5,
};

const styleMouseMove = {
   ...styleDefault,
  strokeWeight: 4.0
};

function applyStyle(/* FeatureStyleFunctionOptions */ params) {
  const datasetFeature = params.feature;
  // Note, 'globalid' is an attribute in this dataset.
  //@ts-ignore
  if (lastClickedFeatureIds.includes(datasetFeature.datasetAttributes['globalid'])) {
    return styleClicked;
  }
  //@ts-ignore
  if (lastInteractedFeatureIds.includes(datasetFeature.datasetAttributes['globalid'])) {
    return styleMouseMove;
  }
  return styleDefault;
}

function createAttribution(map) {
  const attributionLabel = document.createElement('div');

  // Define CSS styles.
  attributionLabel.style.backgroundColor = '#fff';
  attributionLabel.style.opacity = '0.7';
  attributionLabel.style.fontFamily = 'Roboto,Arial,sans-serif';
  attributionLabel.style.fontSize = '10px';
  attributionLabel.style.padding = '2px';
  attributionLabel.style.margin = '2px';
  attributionLabel.textContent = 'Data source: NYC Open Data';
  return attributionLabel;
}

initMap();

JavaScript

let map;
let lastInteractedFeatureIds = [];
let lastClickedFeatureIds = [];
let datasetLayer;

// Note, 'globalid' is an attribute in this Dataset.
function handleClick(/* MouseEvent */ e) {
  if (e.features) {
    lastClickedFeatureIds = e.features.map(
      (f) => f.datasetAttributes["globalid"],
    );
  }

  //@ts-ignore
  datasetLayer.style = applyStyle;
}

function handleMouseMove(/* MouseEvent */ e) {
  if (e.features) {
    lastInteractedFeatureIds = e.features.map(
      (f) => f.datasetAttributes["globalid"],
    );
  }

  //@ts-ignore
  datasetLayer.style = applyStyle;
}

async function initMap() {
  // Request needed libraries.
  const { Map } = await google.maps.importLibrary("maps");
  const position = { lat: 40.780101, lng: -73.96778 };

  map = new Map(document.getElementById("map"), {
    zoom: 13,
    center: position,
    mapId: "b98e588c46685dd7",
    mapTypeControl: false,
  });

  // Dataset ID for NYC park data.
  const datasetId = "6fe13aa9-b900-45e7-b636-3236672c3f4f";

  //@ts-ignore
  datasetLayer = map.getDatasetFeatureLayer(datasetId);
  datasetLayer.style = applyStyle;
  datasetLayer.addListener("click", handleClick);
  datasetLayer.addListener("mousemove", handleMouseMove);
  // Map event listener.
  map.addListener("mousemove", () => {
    // If the map gets a mousemove, that means there are no feature layers
    // with listeners registered under the mouse, so we clear the last
    // interacted feature ids.
    if (lastInteractedFeatureIds?.length) {
      lastInteractedFeatureIds = [];
      datasetLayer.style = applyStyle;
    }
  });

  const attributionDiv = document.createElement("div");
  const attributionControl = createAttribution(map);

  attributionDiv.appendChild(attributionControl);
  map.controls[google.maps.ControlPosition.LEFT_BOTTOM].push(attributionDiv);
}

const styleDefault = {
  strokeColor: "green",
  strokeWeight: 2.0,
  strokeOpacity: 1.0,
  fillColor: "green",
  fillOpacity: 0.3,
};
const styleClicked = {
  ...styleDefault,
  strokeColor: "blue",
  fillColor: "blue",
  fillOpacity: 0.5,
};
const styleMouseMove = {
  ...styleDefault,
  strokeWeight: 4.0,
};

function applyStyle(/* FeatureStyleFunctionOptions */ params) {
  const datasetFeature = params.feature;

  // Note, 'globalid' is an attribute in this dataset.
  //@ts-ignore
  if (
    lastClickedFeatureIds.includes(datasetFeature.datasetAttributes["globalid"])
  ) {
    return styleClicked;
  }

  //@ts-ignore
  if (
    lastInteractedFeatureIds.includes(
      datasetFeature.datasetAttributes["globalid"],
    )
  ) {
    return styleMouseMove;
  }
  return styleDefault;
}

function createAttribution(map) {
  const attributionLabel = document.createElement("div");

  // Define CSS styles.
  attributionLabel.style.backgroundColor = "#fff";
  attributionLabel.style.opacity = "0.7";
  attributionLabel.style.fontFamily = "Roboto,Arial,sans-serif";
  attributionLabel.style.fontSize = "10px";
  attributionLabel.style.padding = "2px";
  attributionLabel.style.margin = "2px";
  attributionLabel.textContent = "Data source: NYC Open Data";
  return attributionLabel;
}

initMap();