arcgis for android 学习 (5) 在地图指定位置添加“标记“，并尝试选中它

 我做一个例子。

   

1.首先显示一个地图。

2. 点击”添加要素“按钮后再次点击地图，将会在地图上添加”红色的位置标记“。 

3.再次点击按钮后，这时，就可以点击刚刚添加的” 红色的位置标记“，就可以查看到”该标记关联到得属性值“

布局：

 <?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/btn1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="添加一个要素" />
    </LinearLayout>

    <!-- MapView layout and initial extent -->
    <com.esri.android.map.MapView
          android:id="@+id/map"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          >
      </com.esri.android.map.MapView>
</LinearLayout>

代码：

 package demo.GraphicsLayerLib;

import java.util.HashMap;
import java.util.Map;

import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

import com.esri.android.map.GraphicsLayer;
import com.esri.android.map.InfoTemplate;
import com.esri.android.map.Layer;
import com.esri.android.map.MapView;
import com.esri.android.map.event.OnSingleTapListener;
import com.esri.core.geometry.Envelope;
import com.esri.core.geometry.Geometry;
import com.esri.core.geometry.Point;
import com.esri.core.map.Graphic;
import com.esri.core.renderer.SimpleRenderer;
import com.esri.core.symbol.PictureMarkerSymbol;
import com.esri.core.symbol.Symbol;

public class GraphicsLayerDemoActivity extends Activity {
    Button btn1;
    MapView mMapView;
    final String URL_STREET_COLD = "http://cache1.arcgisonline.cn/ArcGIS/rest/services/ChinaOnlineStreetCold/MapServer";
    GraphicsLayer mGraphicsLayer;
    final int STATE_ADD_GRAPHIC = 1; // 进入 “添加graphics状态，这时候单击地图时操作就添加graphics
    final int STATE_SHOW = 2;// “选中graphics状态“，这时候单击地图时操作就
                                // 选择一个graphics，并显示该graphics的附加信息”
    int m_State;// 状态

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        m_State = STATE_SHOW;

        btn1 = (Button) findViewById(R.id.btn1);
        btn1.setText("准备添加要素");
        btn1.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // 切换按钮状态，第一次点击本按钮后进入 “添加graphics状态，这时候单击地图时操作就添加graphics”
                // 第一次点击本按钮后进入 “选中graphics状态“，这时候单击地图时操作就
                // 选择一个graphics，并显示该graphics的附加信息”
                m_State = m_State == STATE_ADD_GRAPHIC ? STATE_SHOW
                        : STATE_ADD_GRAPHIC;
                if (m_State == STATE_ADD_GRAPHIC) {
                    btn1.setText("单击地图将添加要素，单击本按钮结束");
                } else {
                    btn1.setText("准备添加要素");
                }
            }
        });

        mMapView = (MapView) findViewById(R.id.map);
        // Add layer to MapView
        mMapView.addLayer(new com.esri.android.map.ags.ArcGISTiledMapServiceLayer(
                URL_STREET_COLD));

        Envelope initextext = new Envelope(12899459.4956466, 4815363.65520802,
                13004178.2243971, 4882704.67712717);
        mMapView.setExtent(initextext);

        // 设定单击事件
        mMapView.setOnSingleTapListener(m_OnSingleTapListener);
    }

    OnSingleTapListener m_OnSingleTapListener = new OnSingleTapListener() {
        int m_Char = 65;

        public void onSingleTap(float x, float y) {
            if (!mMapView.isLoaded()) {
                return;
            }
            if (m_State == STATE_ADD_GRAPHIC) {
                // 获得图层
                AddNewGraphic(x, y);
            } else {// 选中 Graphics
                SelectOneGraphic(x, y);
            }// end if else
        }// end method

        
        private void SelectOneGraphic(float x, float y) {
            // 获得图层
            GraphicsLayer layer = GetGraphicLayer();
            if (layer != null && layer.isInitialized() && layer.isVisible()) {
                Graphic result = null;
                // 检索当前 光标点（手指按压位置）的附近的 graphic对象
                result = GetGraphicsFromLayer(x, y, layer);
                if (result != null) {
                    // 获得附加特别的属性
                    String msgTag = (String) result
                            .getAttributeValue("tag");
                    // 显示提示
                    AlertMsg(msgTag);
                }// end if
            }// end if
        }

        private void AddNewGraphic(float x, float y) {
            GraphicsLayer layer = GetGraphicLayer();
            if (layer != null && layer.isInitialized() && layer.isVisible()) {
                // 转换坐标
                Point pt = mMapView.toMapPoint(new Point(x, y));
                // 附加特别的属性
                Map<String, Object> map = new HashMap<String, Object>();
                map.put("tag", "" + (char) (m_Char++));
                // 创建 graphic对象
                Graphic gp1 = CreateGraphic(pt, map);
                // 添加 Graphics 到图层
                layer.addGraphic(gp1);
            }
        }
    };

    /*
     * 从一个图层里里 查找获得 Graphics对象. x,y是屏幕坐标,layer
     * 是GraphicsLayer目标图层（要查找的）。相差的距离是50像素。
     */
    private Graphic GetGraphicsFromLayer(double xScreen, double yScreen,
            GraphicsLayer layer) {
        Graphic result = null;
        try {
            int[] idsArr = layer.getGraphicIDs();
            double x = xScreen;
            double y = yScreen;
            for (int i = 0; i < idsArr.length; i++) {
                Graphic gpVar = layer.getGraphic(idsArr[i]);
                if (gpVar != null) {
                    Point pointVar = (Point) gpVar.getGeometry();
                    pointVar = mMapView.toScreenPoint(pointVar);
                    double x1 = pointVar.getX();
                    double y1 = pointVar.getY();
                    if (Math.sqrt((x - x1) * (x - x1) + (y - y1) * (y - y1)) < 50) {
                        result = gpVar;
                        break;
                    }
                }
            }
        } catch (Exception e) {
            return null;
        }
        return result;
    }

    /*
     * 创建一个Graphic ， 参数geometry是屏幕坐标位置，map是附加的属性参数
     */
    private Graphic CreateGraphic(Point geometry, Map<String, Object> map) {
        GraphicsLayer layer = GetGraphicLayer();// 获得图层
        Drawable image = GraphicsLayerDemoActivity.this.getBaseContext()
                .getResources().getDrawable(R.drawable.pop);
        PictureMarkerSymbol symbol = new PictureMarkerSymbol(image);

        // 构建graphic
        // Graphic g = new Graphic(geometry, symbol);
        Graphic g = new Graphic(geometry, symbol, map, null);
        return g;
    }

    /*
     * 获得 GetGraphicLayer
     */
    private GraphicsLayer GetGraphicLayer() {
        if (mGraphicsLayer == null) {
            mGraphicsLayer = new GraphicsLayer();
            mMapView.addLayer(mGraphicsLayer);
        }
        return mGraphicsLayer;
    }

    void AlertMsg(String str, Object... arg) {
        String msg = String.format(str, arg);
        Toast.makeText(this, msg, 2).show();
        Log.i("AlertMsg", msg);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
    }

    @Override
    protected void onPause() {
        super.onPause();
        mMapView.pause();
    }

    @Override
    protected void onResume() {
        super.onResume();
        mMapView.unpause();
    }

}

 源代码下载