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
<template>
<div
class="el-tree"
:class="{
'el-tree--highlight-current': highlightCurrent,
'is-dragging': !!dragState.draggingNode,
'is-drop-not-allow': !dragState.allowDrop,
'is-drop-inner': dragState.dropType === 'inner',
}"
role="tree"
>
<app-element-tree-node
v-for="child in root.childNodes"
:node="child"
:props="props"
:render-after-expand="renderAfterExpand"
:show-checkbox="showCheckbox"
:key="getNodeKey(child)"
:render-content="renderContent"
@node-expand="handleNodeExpand"
>
</app-element-tree-node>
<div class="el-tree__empty-block" v-if="isEmpty">
<span class="el-tree__empty-text">{{ emptyText }}</span>
</div>
<div v-show="dragState.showDropIndicator" class="el-tree__drop-indicator" ref="dropIndicator"></div>
</div>
</template>
<script>
import { Tree } from 'element-ui';
import AppElementTreeNode from './app-element-tree-node.vue';
export default {
mixins: [Tree],
components: {
AppElementTreeNode
},
created() {
let dragState = this.dragState;
this.$on('tree-node-drag-start', async (event, treeNode) => {
if (typeof this.allowDrag === 'function' && !(await this.allowDrag(treeNode.node))) {
event.preventDefault();
dragState.draggingNode = null;
return false;
}
event.dataTransfer.effectAllowed = 'move';
// wrap in try catch to address IE's error when first param is 'text/plain'
try {
// setData is required for draggable to work in FireFox
// the content has to be '' so dragging a node out of the tree won't open a new tab in FireFox
event.dataTransfer.setData('text/plain', '');
} catch (e) {}
dragState.draggingNode = treeNode;
this.$emit('node-drag-start', treeNode.node, event);
});
this.$on('tree-node-drag-over', async (event, treeNode) => {
const dropNode = this.findNearestComponent(event.target, 'AppElementTreeNode');
const oldDropNode = dragState.dropNode;
if (oldDropNode && oldDropNode !== dropNode) {
this.removeClass(oldDropNode.$el, 'is-drop-inner');
}
const draggingNode = dragState.draggingNode;
if (!draggingNode || !dropNode) return;
let dropPrev = true;
let dropInner = true;
let dropNext = true;
let userAllowDropInner = true;
if (typeof this.allowDrop === 'function') {
dropPrev = await this.allowDrop(draggingNode.node, dropNode.node, 'prev');
userAllowDropInner = dropInner = await this.allowDrop(draggingNode.node, dropNode.node, 'inner');
dropNext = await this.allowDrop(draggingNode.node, dropNode.node, 'next');
}
event.dataTransfer.dropEffect = dropInner ? 'move' : 'none';
if ((dropPrev || dropInner || dropNext) && oldDropNode !== dropNode) {
if (oldDropNode) {
this.$emit('node-drag-leave', draggingNode.node, oldDropNode.node, event);
}
this.$emit('node-drag-enter', draggingNode.node, dropNode.node, event);
}
if (dropPrev || dropInner || dropNext) {
dragState.dropNode = dropNode;
}
if (dropNode.node.nextSibling === draggingNode.node) {
dropNext = false;
}
if (dropNode.node.previousSibling === draggingNode.node) {
dropPrev = false;
}
if (dropNode.node.contains(draggingNode.node, false)) {
dropInner = false;
}
if (draggingNode.node === dropNode.node || draggingNode.node.contains(dropNode.node)) {
dropPrev = false;
dropInner = false;
dropNext = false;
}
const targetPosition = dropNode.$el.getBoundingClientRect();
const treePosition = this.$el.getBoundingClientRect();
let dropType;
const prevPercent = dropPrev ? (dropInner ? 0.25 : dropNext ? 0.45 : 1) : -1;
const nextPercent = dropNext ? (dropInner ? 0.75 : dropPrev ? 0.55 : 0) : 1;
let indicatorTop = -9999;
const distance = event.clientY - targetPosition.top;
if (distance < targetPosition.height * prevPercent) {
dropType = 'before';
} else if (distance > targetPosition.height * nextPercent) {
dropType = 'after';
} else if (dropInner) {
dropType = 'inner';
} else {
dropType = 'none';
}
const iconPosition = dropNode.$el.querySelector('.el-tree-node__expand-icon').getBoundingClientRect();
const dropIndicator = this.$refs.dropIndicator;
if (dropType === 'before') {
indicatorTop = iconPosition.top - treePosition.top;
} else if (dropType === 'after') {
indicatorTop = iconPosition.bottom - treePosition.top;
}
dropIndicator.style.top = indicatorTop + 'px';
dropIndicator.style.left = iconPosition.right - treePosition.left + 'px';
if (dropType === 'inner') {
this.addClass(dropNode.$el, 'is-drop-inner');
} else {
this.removeClass(dropNode.$el, 'is-drop-inner');
}
dragState.showDropIndicator = dropType === 'before' || dropType === 'after';
dragState.allowDrop = dragState.showDropIndicator || userAllowDropInner;
dragState.dropType = dropType;
this.$emit('node-drag-over', draggingNode.node, dropNode.node, event);
});
},
methods: {
findNearestComponent(element, componentName) {
let target = element;
while (target && target.tagName !== 'BODY') {
if (target.__vue__ && target.__vue__.$options.name === componentName) {
return target.__vue__;
}
target = target.parentNode;
}
return null;
},
removeClass(el, cls) {
if (!el || !cls) return;
var classes = cls.split(' ');
var curClass = ' ' + el.className + ' ';
for (var i = 0, j = classes.length; i < j; i++) {
var clsName = classes[i];
if (!clsName) continue;
if (el.classList) {
el.classList.remove(clsName);
} else if (hasClass(el, clsName)) {
curClass = curClass.replace(' ' + clsName + ' ', ' ');
}
}
if (!el.classList) {
el.setAttribute('class', trim(curClass));
}
},
addClass(el, cls) {
if (!el) return;
var curClass = el.className;
var classes = (cls || '').split(' ');
for (var i = 0, j = classes.length; i < j; i++) {
var clsName = classes[i];
if (!clsName) continue;
if (el.classList) {
el.classList.add(clsName);
} else if (!hasClass(el, clsName)) {
curClass += ' ' + clsName;
}
}
if (!el.classList) {
el.setAttribute('class', curClass);
}
},
},
};
</script>