1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'test_widgets.dart';
class TestParentData {
TestParentData({ this.top, this.right, this.bottom, this.left });
final double top;
final double right;
final double bottom;
final double left;
}
void checkTree(WidgetTester tester, List<TestParentData> expectedParentData) {
final MultiChildRenderObjectElement element = tester.element(
find.byElementPredicate((Element element) => element is MultiChildRenderObjectElement)
);
expect(element, isNotNull);
expect(element.renderObject is RenderStack, isTrue);
final RenderStack renderObject = element.renderObject;
try {
RenderObject child = renderObject.firstChild;
for (TestParentData expected in expectedParentData) {
expect(child is RenderDecoratedBox, isTrue);
final RenderDecoratedBox decoratedBox = child;
expect(decoratedBox.parentData is StackParentData, isTrue);
final StackParentData parentData = decoratedBox.parentData;
expect(parentData.top, equals(expected.top));
expect(parentData.right, equals(expected.right));
expect(parentData.bottom, equals(expected.bottom));
expect(parentData.left, equals(expected.left));
final StackParentData decoratedBoxParentData = decoratedBox.parentData;
child = decoratedBoxParentData.nextSibling;
}
expect(child, isNull);
} catch (e) {
print(renderObject.toStringDeep());
rethrow;
}
}
final TestParentData kNonPositioned = TestParentData();
void main() {
testWidgets('ParentDataWidget control test', (WidgetTester tester) async {
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
DecoratedBox(decoration: kBoxDecorationA),
Positioned(
top: 10.0,
left: 10.0,
child: DecoratedBox(decoration: kBoxDecorationB),
),
DecoratedBox(decoration: kBoxDecorationC),
],
),
);
checkTree(tester, <TestParentData>[
kNonPositioned,
TestParentData(top: 10.0, left: 10.0),
kNonPositioned,
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
Positioned(
bottom: 5.0,
right: 7.0,
child: DecoratedBox(decoration: kBoxDecorationA),
),
Positioned(
top: 10.0,
left: 10.0,
child: DecoratedBox(decoration: kBoxDecorationB),
),
DecoratedBox(decoration: kBoxDecorationC),
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(bottom: 5.0, right: 7.0),
TestParentData(top: 10.0, left: 10.0),
kNonPositioned,
]);
const DecoratedBox kDecoratedBoxA = DecoratedBox(decoration: kBoxDecorationA);
const DecoratedBox kDecoratedBoxB = DecoratedBox(decoration: kBoxDecorationB);
const DecoratedBox kDecoratedBoxC = DecoratedBox(decoration: kBoxDecorationC);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
Positioned(
bottom: 5.0,
right: 7.0,
child: kDecoratedBoxA,
),
Positioned(
top: 10.0,
left: 10.0,
child: kDecoratedBoxB,
),
kDecoratedBoxC,
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(bottom: 5.0, right: 7.0),
TestParentData(top: 10.0, left: 10.0),
kNonPositioned,
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
Positioned(
bottom: 6.0,
right: 8.0,
child: kDecoratedBoxA,
),
Positioned(
left: 10.0,
right: 10.0,
child: kDecoratedBoxB,
),
kDecoratedBoxC,
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(bottom: 6.0, right: 8.0),
TestParentData(left: 10.0, right: 10.0),
kNonPositioned,
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: <Widget>[
kDecoratedBoxA,
Positioned(
left: 11.0,
right: 12.0,
child: Container(child: kDecoratedBoxB),
),
kDecoratedBoxC,
],
),
);
checkTree(tester, <TestParentData>[
kNonPositioned,
TestParentData(left: 11.0, right: 12.0),
kNonPositioned,
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: <Widget>[
kDecoratedBoxA,
Positioned(
right: 10.0,
child: Container(child: kDecoratedBoxB),
),
Container(
child: const Positioned(
top: 8.0,
child: kDecoratedBoxC,
),
),
],
),
);
checkTree(tester, <TestParentData>[
kNonPositioned,
TestParentData(right: 10.0),
TestParentData(top: 8.0),
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
Positioned(
right: 10.0,
child: FlipWidget(left: kDecoratedBoxA, right: kDecoratedBoxB),
),
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(right: 10.0),
]);
flipStatefulWidget(tester);
await tester.pump();
checkTree(tester, <TestParentData>[
TestParentData(right: 10.0),
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
Positioned(
top: 7.0,
child: FlipWidget(left: kDecoratedBoxA, right: kDecoratedBoxB),
),
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(top: 7.0),
]);
flipStatefulWidget(tester);
await tester.pump();
checkTree(tester, <TestParentData>[
TestParentData(top: 7.0),
]);
await tester.pumpWidget(
Stack(textDirection: TextDirection.ltr)
);
checkTree(tester, <TestParentData>[]);
});
testWidgets('ParentDataWidget conflicting data', (WidgetTester tester) async {
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: const <Widget>[
Positioned(
top: 5.0,
bottom: 8.0,
child: Positioned(
top: 6.0,
left: 7.0,
child: DecoratedBox(decoration: kBoxDecorationB),
),
),
],
),
);
dynamic exception = tester.takeException();
expect(exception, isFlutterError);
expect(
exception.toString(),
equalsIgnoringHashCodes(
'Incorrect use of ParentDataWidget.\n'
'Positioned widgets must be placed directly inside Stack widgets.\n'
'Positioned(no depth, left: 7.0, top: 6.0, dirty) has a Stack ancestor, but there are other widgets between them:\n'
'- Positioned(top: 5.0, bottom: 8.0) (this is a different Positioned than the one with the problem)\n'
'These widgets cannot come between a Positioned and its Stack.\n'
'The ownership chain for the parent of the offending Positioned was:\n'
' Positioned ← Stack ← [root]'
),
);
await tester.pumpWidget(Stack(textDirection: TextDirection.ltr));
checkTree(tester, <TestParentData>[]);
await tester.pumpWidget(
Container(
child: Row(
children: const <Widget>[
Positioned(
top: 6.0,
left: 7.0,
child: DecoratedBox(decoration: kBoxDecorationB),
),
],
),
),
);
exception = tester.takeException();
expect(exception, isFlutterError);
expect(
exception.toString(),
equalsIgnoringHashCodes(
'Incorrect use of ParentDataWidget.\n'
'Positioned widgets must be placed inside Stack widgets.\n'
'Positioned(no depth, left: 7.0, top: 6.0, dirty) has no Stack ancestor at all.\n'
'The ownership chain for the parent of the offending Positioned was:\n'
' Row ← Container ← [root]'
)
);
await tester.pumpWidget(
Stack(textDirection: TextDirection.ltr)
);
checkTree(tester, <TestParentData>[]);
});
testWidgets('ParentDataWidget interacts with global keys', (WidgetTester tester) async {
final GlobalKey key = GlobalKey();
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: <Widget>[
Positioned(
top: 10.0,
left: 10.0,
child: DecoratedBox(key: key, decoration: kBoxDecorationA),
),
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(top: 10.0, left: 10.0),
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: <Widget>[
Positioned(
top: 10.0,
left: 10.0,
child: DecoratedBox(
decoration: kBoxDecorationB,
child: DecoratedBox(key: key, decoration: kBoxDecorationA),
),
),
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(top: 10.0, left: 10.0),
]);
await tester.pumpWidget(
Stack(
textDirection: TextDirection.ltr,
children: <Widget>[
Positioned(
top: 10.0,
left: 10.0,
child: DecoratedBox(key: key, decoration: kBoxDecorationA),
),
],
),
);
checkTree(tester, <TestParentData>[
TestParentData(top: 10.0, left: 10.0),
]);
});
testWidgets('Parent data invalid ancestor', (WidgetTester tester) async {
await tester.pumpWidget(Row(
children: <Widget>[
Stack(
textDirection: TextDirection.ltr,
children: <Widget>[
Expanded(
child: Container(),
),
],
),
],
));
final dynamic exception = tester.takeException();
expect(exception, isFlutterError);
expect(
exception.toString(),
equalsIgnoringHashCodes(
'Incorrect use of ParentDataWidget.\n'
'Expanded widgets must be placed directly inside Flex widgets.\n'
'Expanded(no depth, flex: 1, dirty) has a Flex ancestor, but there are other widgets between them:\n'
'- Stack(alignment: AlignmentDirectional.topStart, textDirection: ltr, fit: loose, overflow: clip)\n'
'These widgets cannot come between a Expanded and its Flex.\n'
'The ownership chain for the parent of the offending Expanded was:\n'
' Stack ← Row ← [root]'
),
);
});
}