ArcGIS for Android 100.3.0（17）：SketchEditor(草图编辑器)

SketchEditor

表示草图编辑器，允许用户在地图视图上以交互方式绘制几何图形。通过使用相应的SketchCreationMode启动SketchEditor，可以从头开始绘制不同的几何类型，例如点，多点，折线或多边形。

构造方法

public SketchEditor ()

常用方法

//如果草图有效，则获取当前几何
public Geometry getGeometry （）

//指示草图几何体是否有效
public boolean isSketchValid （）

//撤消草图几何体的最后一个动作
public void undo （）

//重做草图几何体的最后一个动作
public void redo （）

//如果草图会话已启动，则停止该草绘会话。getGeometry()在调用stop之前可以获得最终的草图几何。
public void stop （）

//为给定的草图创建模式启动新的编辑会话
public void start （SketchCreationMode creationMode）

//设置草图几何体的不透明度
public void setOpacity （float opacity）

看官网例子就能掌握SketchEditor的用法：

/**
 * SketchEditor:表示草图编辑器，允许用户在地图视图上以交互方式绘制几何图形。
 */
public class SketchEditorActivity extends AppCompatActivity {

    private final String TAG = MainActivity.class.getSimpleName();

    private SimpleMarkerSymbol mPointSymbol;
    private SimpleLineSymbol mLineSymbol;
    private SimpleFillSymbol mFillSymbol;
    private MapView mMapView;
    private SketchEditor mSketchEditor;
    private GraphicsOverlay mGraphicsOverlay;

    private ImageButton mPointButton;
    private ImageButton mMultiPointButton;
    private ImageButton mPolylineButton;
    private ImageButton mPolygonButton;
    private ImageButton mFreehandLineButton;
    private ImageButton mFreehandPolygonButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sketch_editor);

        mMapView = findViewById(R.id.mapView);
        ArcGISMap map = new ArcGISMap(Basemap.Type.LIGHT_GRAY_CANVAS, 34.056295, -117.195800, 16);
        mMapView.setMap(map);

        mGraphicsOverlay = new GraphicsOverlay();
        mMapView.getGraphicsOverlays().add(mGraphicsOverlay);

        // 创建一个新的草图编辑器并将其添加到地图视图中
        mSketchEditor = new SketchEditor();
        mMapView.setSketchEditor(mSketchEditor);

        mPointSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbol.Style.SQUARE, 0xFFFF0000, 20);
        mLineSymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, 0xFFFF8800, 4);
        mFillSymbol = new SimpleFillSymbol(SimpleFillSymbol.Style.CROSS, 0x40FFA9A9, mLineSymbol);

        initViews();
    }

    private void initViews() {
        // get buttons from layouts
        mPointButton = findViewById(R.id.pointButton);
        mMultiPointButton = findViewById(R.id.pointsButton);
        mPolylineButton = findViewById(R.id.polylineButton);
        mPolygonButton = findViewById(R.id.polygonButton);
        mFreehandLineButton = findViewById(R.id.freehandLineButton);
        mFreehandPolygonButton = findViewById(R.id.freehandPolygonButton);

        // add click listeners
        mPointButton.setOnClickListener(view -> createModePoint());
        mMultiPointButton.setOnClickListener(view -> createModeMultipoint());
        mPolylineButton.setOnClickListener(view -> createModePolyline());
        mPolygonButton.setOnClickListener(view -> createModePolygon());
        mFreehandLineButton.setOnClickListener(view -> createModeFreehandLine());
        mFreehandPolygonButton.setOnClickListener(view -> createModeFreehandPolygon());
    }

    /**
     * 单击point按钮时，重置其他按钮，显示选中的point按钮和开始点绘图模式。
     */
    private void createModePoint() {
        resetButtons();
        mPointButton.setSelected(true);
        mSketchEditor.start(SketchCreationMode.POINT);
    }

    /**
     * 单击multipoint按钮时，重置其他按钮，显示选中的multipoint按钮，然后开始多点绘图模式。
     */
    private void createModeMultipoint() {
        resetButtons();
        mMultiPointButton.setSelected(true);
        mSketchEditor.start(SketchCreationMode.MULTIPOINT);
    }

    /**
     * 单击折线按钮时，重置其他按钮，显示选中的折线按钮，然后开始折线图模式。
     */
    private void createModePolyline() {
        resetButtons();
        mPolylineButton.setSelected(true);
        mSketchEditor.start(SketchCreationMode.POLYLINE);

    }

    /**
     * 当单击多边形按钮时，重置其他按钮，显示选中的多边形按钮，并启动多边形绘图模式。
     */
    private void createModePolygon() {
        resetButtons();
        mPolygonButton.setSelected(true);
        mSketchEditor.start(SketchCreationMode.POLYGON);
    }

    /**
     * 单击FREEHAND_LINE按钮时，重置其他按钮，显示选定的FREEHAND_LINE按钮，和开始徒手画线模式。
     */
    private void createModeFreehandLine() {
        resetButtons();
        mFreehandLineButton.setSelected(true);
        mSketchEditor.start(SketchCreationMode.FREEHAND_LINE);
    }

    /**
     * 单击FREEHAND_POLYGON按钮时，重置其他按钮，显示选定的FREEHAND_POLYGON按钮，并启用徒手绘制多边形模式。
     */
    private void createModeFreehandPolygon() {
        resetButtons();
        mFreehandPolygonButton.setSelected(true);
        mSketchEditor.start(SketchCreationMode.FREEHAND_POLYGON);
    }

    /**
     * 当单击undo按钮时，撤消SketchEditor上的最后一个事件。
     */
    private void undo() {
        if (mSketchEditor.canUndo()) {
            mSketchEditor.undo();
        }
    }

    /**
     * 当单击redo按钮时，在SketchEditor上重做最后一个未完成的事件。
     */
    private void redo() {
        if (mSketchEditor.canRedo()) {
            mSketchEditor.redo();
        }
    }

    /**
     * 当单击停止按钮时，检查草图是否有效。如果是，从草图中得到几何图形，设置它将其添加到图形覆盖层。
     */
    private void stop() {
        if (!mSketchEditor.isSketchValid()) {
            reportNotValid(); //如果草图无效，则调用。向用户报告草图无效的原因。
            mSketchEditor.stop();
            resetButtons();
            return;
        }

        // 从草图编辑器获得几何图形
        Geometry sketchGeometry = mSketchEditor.getGeometry();
        mSketchEditor.stop();
        resetButtons();

        if (sketchGeometry != null) {

            //从草图编辑器创建一个图形
            Graphic graphic = new Graphic(sketchGeometry);

            // 根据几何类型分配符号
            if (graphic.getGeometry().getGeometryType() == GeometryType.POLYGON) {
                graphic.setSymbol(mFillSymbol);
            } else if (graphic.getGeometry().getGeometryType() == GeometryType.POLYLINE) {
                graphic.setSymbol(mLineSymbol);
            } else if (graphic.getGeometry().getGeometryType() == GeometryType.POINT ||
                    graphic.getGeometry().getGeometryType() == GeometryType.MULTIPOINT) {
                graphic.setSymbol(mPointSymbol);
            }

            // 将图形添加到图形覆盖层
            mGraphicsOverlay.getGraphics().add(graphic);
        }
    }

    /**
     * 如果草图无效，则调用。向用户报告草图无效的原因。
     */
    private void reportNotValid() {
        String validIf;
        if (mSketchEditor.getSketchCreationMode() == SketchCreationMode.POINT) {
            validIf = "Point only valid if it contains an x & y coordinate.";
        } else if (mSketchEditor.getSketchCreationMode() == SketchCreationMode.MULTIPOINT) {
            validIf = "Multipoint only valid if it contains at least one vertex.";
        } else if (mSketchEditor.getSketchCreationMode() == SketchCreationMode.POLYLINE
                || mSketchEditor.getSketchCreationMode() == SketchCreationMode.FREEHAND_LINE) {
            validIf = "Polyline only valid if it contains at least one part of 2 or more vertices.";
        } else if (mSketchEditor.getSketchCreationMode() == SketchCreationMode.POLYGON
                || mSketchEditor.getSketchCreationMode() == SketchCreationMode.FREEHAND_POLYGON) {
            validIf = "Polygon only valid if it contains at least one part of 3 or more vertices which form a closed ring.";
        } else {
            validIf = "No sketch creation mode selected.";
        }
        String report = "Sketch geometry invalid:\n" + validIf;
        Snackbar reportSnackbar = Snackbar.make(findViewById(R.id.toolbarInclude), report, Snackbar.LENGTH_INDEFINITE);
        reportSnackbar.setAction("Dismiss", view -> reportSnackbar.dismiss());
        TextView snackbarTextView = reportSnackbar.getView().findViewById(android.support.design.R.id.snackbar_text);
        snackbarTextView.setSingleLine(false);
        reportSnackbar.show();
        Log.e(TAG, report);
    }

    /**
     * De-selects all buttons.
     */
    private void resetButtons() {
        mPointButton.setSelected(false);
        mMultiPointButton.setSelected(false);
        mPolylineButton.setSelected(false);
        mPolygonButton.setSelected(false);
        mFreehandLineButton.setSelected(false);
        mFreehandPolygonButton.setSelected(false);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.undo_redo_stop_menu, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.undo) {
            undo();
        } else if (id == R.id.redo) {
            redo();
        } else if (id == R.id.stop) {
            stop();
        }
        return super.onOptionsItemSelected(item);
    }

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

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

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