コンテキスト関連メニューは、PCでマウスの右ボタンを押して表示されるメニューと似ていますが、Androidプラットフォームでは長押しでコンテキストメニューを起動し、一般的に現在のUIコンテンツに関連するメニューを表示するために使用されます。
コンテキストメニューの使い方は、オプションメニューとよく似ています：
<?xml version=”1.0 encoding=”utf-8″?>
<menu
xmlns:android=”http://..com/apk/res/android >
<item
android:id=”@+id/mnuOval”
android:title=”Oval”>
</item>
<item
android:id=”@+id/mnuPear”
android:title=”Pear”>
</item>
<item
android:id=”@+id/mnuShape2DDemo”
android:title=”Shape2D”>
</item>
</menu>
コンテキストメニューの展開はonCreateContextMenuメソッドで行います：
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_context_shape, menu);
}
コンテキストメニューイベントを処理します：
@Override
public boolean onContextItemSelected(MenuItem item) {
menuOption = item.getItemId();
drawImage();
return super.onContextItemSelected(item);
}
ビューを長押ししたときにコンテキストメニューを表示するには、ビューにコンテキストメニューを登録する必要があります：
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
registerForContextMenu(graphic2dView);
}
全コードは以下の通り：
1 public class Shape extends Graphics2DActivity {
2
3 private int menuOption;
4
5 public void onCreate(Bundle savedInstanceState) {
6 super.onCreate(savedInstanceState);
7 registerForContextMenu(graphic2dView);
8 }
9
10 @Override
11 protected void drawImage() {
12 switch (menuOption) {
13 case R.id.mnuOval:
14 drawOval();
15 break;
16 case R.id.mnuPear:
17 drawPear();
18 break;
19 case R.id.mnuShape2DDemo:
20 drawShape2D();
21 break;
22 default:
23 drawOval();
24 break;
25 }
26 graphic2dView.refreshCanvas();
27
28 }
29
30 @Override
31 public void onCreateContextMenu(ContextMenu menu, View v,
32 ContextMenuInfo menuInfo) {
33 super.onCreateContextMenu(menu, v, menuInfo);
34 MenuInflater inflater = getMenuInflater();
35 inflater.inflate(R.menu.menu_context_shape, menu);
36 }
37
38 @Override
39 public boolean onContextItemSelected(MenuItem item) {
40
41 menuOption = item.getItemId();
42 drawImage();
43 return super.onContextItemSelected(item);
44
45 }
46
47 private void drawOval() {
48 AffineTransform mat1;
49
50 /** Colors */
51 Color redColor = new Color(0x96ff0000, true);
52 Color greenColor = new Color(0xff00ff00);
53 mat1 = new AffineTransform();
54 mat1.translate(30, 40);
55 mat1.rotate(-30 * Math.PI / 180.0);
56 // Clear the canvas with white color.
57 graphics2D.clear(Color.WHITE);
58 graphics2D.Reset();
59
60 graphics2D.setAffineTransform(new AffineTransform());
61 SolidBrush brush = new SolidBrush(greenColor);
62 graphics2D.fillOval(brush, 20, 60, 100, 50);
63
64 com.mapdigit.drawing.Pen pen
65 = new com.mapdigit.drawing.Pen(redColor, 5);
66 graphics2D.setAffineTransform(mat1);
67 graphics2D.drawOval(pen, 20, 60, 100, 50);
68 }
69
70 private void drawPear() {
71 Ellipse circle, oval, leaf, stem;
72 Area circ, ov, leaf1, leaf2, st1, st2;
73 circle = new Ellipse();
74 oval = new Ellipse();
75 leaf = new Ellipse();
76 stem = new Ellipse();
77 circ = new Area(circle);
78 ov = new Area(oval);
79 leaf1 = new Area(leaf);
80 leaf2 = new Area(leaf);
81 st1 = new Area(stem);
82 st2 = new Area(stem);
83 graphics2D.clear(Color.WHITE);
84 graphics2D.Reset();
85 int w = SharedGraphics2DInstance.CANVAS_WIDTH;
86 int h = SharedGraphics2DInstance.CANVAS_HEIGHT;
87 int ew = w / 2;
88 int eh = h / 2;
89 SolidBrush brush = new SolidBrush(Color.GREEN);
90 graphics2D.setDefaultBrush(brush);
91 // Creates the first leaf by filling the
92 //intersection of two Area
93 // objects created from an ellipse.
94 leaf.setFrame(ew - 16, eh - 29, 15, 15);
95 leaf1 = new Area(leaf);
96 leaf.setFrame(ew - 14, eh - 47, 30, 30);
97 leaf2 = new Area(leaf);
98 leaf1.intersect(leaf2);
99 graphics2D.fill(null, leaf1);
100
101 // Creates the second leaf.
102 leaf.setFrame(ew + 1, eh - 29, 15, 15);
103 leaf1 = new Area(leaf);
104 leaf2.intersect(leaf1);
105 graphics2D.fill(null, leaf2);
106
107 brush = new SolidBrush(Color.BLACK);
108 graphics2D.setDefaultBrush(brush);
109
110 // Creates the stem by filling the Area
111 //resulting from the subtraction of two
112 //Area objects created from an ellipse.
113 stem.setFrame(ew, eh - 42, 40, 40);
114 st1 = new Area(stem);
115 stem.setFrame(ew + 3, eh - 47, 50, 50);
116 st2 = new Area(stem);
117 st1.subtract(st2);
118 graphics2D.fill(null, st1);
119
120 brush = new SolidBrush(Color.YELLOW);
121 graphics2D.setDefaultBrush(brush);
122
123 // Creates the pear itself by filling the
124 //Area resulting from the union of two Area
125 //objects created by two different ellipses.
126 circle.setFrame(ew - 25, eh, 50, 50);
127 oval.setFrame(ew - 19, eh - 20, 40, 70);
128 circ = new Area(circle);
129 ov = new Area(oval);
130 circ.add(ov);
131 graphics2D.fill(null, circ);
132 }
133
134 private void drawShape2D() {
135 Color bg = Color.white;
136 Color fg = Color.black;
137 Color red = Color.red;
138 Color white = Color.white;
139 com.mapdigit.drawing.Pen pen
140 = new com.mapdigit.drawing.Pen(fg, 1);
141 SolidBrush brush = new SolidBrush(red);
142 // Clear the canvas with white color.
143 graphics2D.clear(bg);
144 graphics2D.Reset();
145 Dimension d = new Dimension(SharedGraphics2DInstance.CANVAS_WIDTH,
146 SharedGraphics2DInstance.CANVAS_HEIGHT);
147 int gridWidth = d.width / 2;
148 int gridHeight = d.height / 6;
149
150 int x = 5;
151 int y = 7;
152 int rectWidth = gridWidth - 2 * x;
153 int stringY = gridHeight - 3 - 2 - 16;
154 int rectHeight = stringY - y - 2;
155 graphics2D.draw(pen, new Line(x, y + rectHeight - 1,
156 x + rectWidth, y));
157 x += gridWidth;
158 graphics2D.draw(pen, new Rectangle(x, y, rectWidth,
159 rectHeight));
160 x += gridWidth;
161 x = 5;
162 y += gridHeight;
163 stringY += gridHeight;
164 graphics2D.draw(pen, new RoundRectangle(x, y, rectWidth,
165 rectHeight,
166 10, 10));
167 x += gridWidth;
168 graphics2D.draw(pen, new Arc(x, y, rectWidth,
169 rectHeight, 90, 135,
170 Arc.OPEN));
171 x = 5;
172 y += gridHeight;
173 stringY += gridHeight;
174 graphics2D.draw(pen, new Ellipse(x, y, rectWidth,
175 rectHeight));
176 x += gridWidth;
177 // draw GeneralPath (polygon)
178 int x1Points[] = { x, x + rectWidth, x,
179 x + rectWidth };
180 int y1Points[] = { y, y + rectHeight,
181 y + rectHeight, y };
182 com.mapdigit.drawing.geometry.Path polygon
183 = new com.mapdigit.drawing.geometry.Path(
184 com.mapdigit.drawing.geometry.Path.WIND_EVEN_ODD,
185 x1Points.length);
186 polygon.moveTo(x1Points[0], y1Points[0]);
187 for (int index = 1; index < x1Points.length; index++) {
188 polygon.lineTo(x1Points[index], y1Points[index]);
189 }
190 polygon.closePath();
191 graphics2D.draw(pen, polygon);
192 x = 5;
193 y += gridHeight;
194 stringY += gridHeight;
195 int x2Points[] = { x, x + rectWidth, x, x + rectWidth };
196 int y2Points[] = { y, y + rectHeight, y + rectHeight, y };
197 com.mapdigit.drawing.geometry.Path polyline
198 = new com.mapdigit.drawing.geometry.Path(
199 com.mapdigit.drawing.geometry.Path.WIND_EVEN_ODD,
200 x2Points.length);
201 polyline.moveTo(x2Points[0], y2Points[0]);
202 for (int index = 1; index < x2Points.length; index++) {
203 polyline.lineTo(x2Points[index], y2Points[index]);
204 }
205 graphics2D.draw(pen, polyline);
206 x += gridWidth;
207 graphics2D.setPenAndBrush(pen, brush);
208 graphics2D.fill(null,
209 new Rectangle(x, y, rectWidth, rectHeight));
210 graphics2D.draw(null,
211 new Rectangle(x, y, rectWidth, rectHeight));
212 x = 5;
213 y += gridHeight;
214 stringY += gridHeight;
215 Color[] colors = new Color[] { red, white };
216 int[] fractions = new int[] { 0, 255 };
217 LinearGradientBrush redtowhite
218 = new LinearGradientBrush(x, y, x
219 + rectWidth, y, fractions, colors,
220 com.mapdigit.drawing.Brush.NO_CYCLE);
221 graphics2D.setPenAndBrush(pen, redtowhite);
222 graphics2D.fill(null, new RoundRectangle(x, y, rectWidth,
223 rectHeight,
224 10, 10));
225 graphics2D.draw(null, new RoundRectangle(x, y, rectWidth,
226 rectHeight,
227 10, 10));
228 x += gridWidth;
229 graphics2D.setPenAndBrush(pen, brush);
230 graphics2D.fill(null, new Arc(x, y, rectWidth,
231 rectHeight, 90, 135,
232 Arc.CHORD));
233 graphics2D.draw(null, new Arc(x, y, rectWidth,
234 rectHeight, 90, 135,
235 Arc.CHORD));
236 x = 5;
237 y += gridHeight;
238 stringY += gridHeight;
239 int x3Points[] = { x, x + rectWidth, x, x + rectWidth };
240 int y3Points[] = { y, y + rectHeight, y + rectHeight, y };
241 com.mapdigit.drawing.geometry.Path filledPolygon
242 = new com.mapdigit.drawing.geometry.Path(
243 com.mapdigit.drawing.geometry.Path.WIND_EVEN_ODD,
244 x3Points.length);
245 filledPolygon.moveTo(x3Points[0], y3Points[0]);
246 for (int index = 1; index < x3Points.length; index++) {
247 filledPolygon.lineTo(x3Points[index], y3Points[index]);
248 }
249 filledPolygon.closePath();
250 graphics2D.setPenAndBrush(pen, brush);
251 graphics2D.fill(null, filledPolygon);
252 graphics2D.draw(null, filledPolygon);
253
254 }
255 }
メニュー ここで説明した機能に加えて、Androidは動的メニューや動的に変更されるメニューもサポートしています。詳しくはAndroidのドキュメントを参照してください。
