Big Bug Ban

最近需要实现一个如下图所示的列表

但是系统提供的GridView抑或是ListView均不能实现item自动排列

于是自己实现了一个

核心在于自己实现了adaper和view添加的事件，添加的时候决定是否生成一个新的line来容纳item

另外注意这个实现有一处优化的地方。

即若到第三行的时候，第三行放不下，会尝试从第一行开始计算，这样可以尽可能保证每行都是好看的效果

1.  
2.  
3. /**
4.  * Copyright 2013
5.  * Created on : 13-11-27 , 上午11:53
6.  * Author     : haku
7.  * Blog       : http://haku.hk
8.  */
9. public class AutoFitLinearLayout extends LinearLayout {
10.  
11.     private DataSetObserver obv;
12.     private BaseAdapter adapter;
13.     private ArrayList<LinearLayout> lineViews = new ArrayList<LinearLayout>();
14.  
15.     private AdapterView.OnItemClickListener itemClickListener;
16.  
17.     private class ItemProxyClickListener implements OnClickListener {
18.         int pos;
19.  
20.         ItemProxyClickListener(int pos) {
21.             this.pos = pos;
22.         }
23.  
24.         @Override
25.         public void onClick(View v) {
26.             itemClickListener.onItemClick(null, v, pos, 0);
27.         }
28.     }
29.  
30.     public AutoFitLinearLayout(Context context, AttributeSet attrs) {
31.         super(context, attrs);
32.         this.setOrientation(LinearLayout.VERTICAL);
33.     }
34.  
35.     public AutoFitLinearLayout(Context context) {
36.         super(context);
37.         this.setOrientation(LinearLayout.VERTICAL);
38.     }
39.  
40.     /**
41.      * 清空绑定view
42.      */
43.     public void reset() {
44.         int total = lineViews.size();
45.         for (int i = 0; i < total; i++) {
46.             this.removeView(lineViews.get(i));
47.         }
48.         lineViews.clear();
49.     }
50.  
51.     /**
52.      * @param adp
53.      */
54.     public void setAdapter(BaseAdapter adp) {
55.         adapter = adp;
56.         obv = new DataSetObserver() {
57.             @Override
58.             public void onChanged() {
59.                 super.onChanged();
60.                 reset();
61.                 int total = adapter.getCount();
62.                 for (int i = 0; i < total; i++) {
63.                     View v = adapter.getView(i, null, getLastLineHolder());
64.                     if (getItemClickListener() != null) {
65.                         v.setOnClickListener(new ItemProxyClickListener(i));
66.                     }
67.                     addToSuitableLayout(v);
68.                 }
69.             }
70.         };
71.         adapter.registerDataSetObserver(this.obv);
72.     }
73.  
74.     public void addToSuitableLayout(View v) {
75.         LinearLayout suitableLayout = getBestLineHolder(v);
76.         suitableLayout.addView(v);
77.         // 添加子view后重新计算宽度
78.         suitableLayout.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
79.     }
80.  
81.     /**
82.      * 添加一个水平的layout
83.      *
84.      * @return
85.      */
86.     public LinearLayout addNewLineHolder() {
87.         LinearLayout v = new LinearLayout(this.getContext());
88.  
89.         LayoutParams layoutParams = new LayoutParams(
90.                 ViewGroup.LayoutParams.MATCH_PARENT,
91.                 ViewGroup.LayoutParams.WRAP_CONTENT);
92.  
93.         v.setOrientation(LinearLayout.HORIZONTAL);
94.         v.setLayoutParams(layoutParams);
95.         lineViews.add(v);
96.         this.addView(v);
97.         return v;
98.     }
99.  
100.     /**
101.      * 自动计算宽度后反馈line holder
102.      *
103.      * @return
104.      */
105.     public LinearLayout getBestLineHolder(View v) {
106.         // 计算子view的宽度和margin
107.         v.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
108.         int viewWidth = v.getMeasuredWidth();
109.         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) v.getLayoutParams();
110.  
111.         if (lineViews.isEmpty()) {
112.             this.addNewLineHolder();
113.         }
114.         LinearLayout lHolder;
115.         // 遍历所有存在的line，计算剩余宽度，如果适合就返回
116.         for (int i = 0, size = lineViews.size(); i < size; i++) {
117.             lHolder = lineViews.get(i);
118.             int lineMaxWidth = lHolder.getMeasuredWidth();
119.             if (lineMaxWidth + viewWidth + lp.leftMargin + lp.rightMargin < this.getMeasuredWidth()) {
120.                 return lHolder;
121.             }
122.         }
123.         lHolder = this.addNewLineHolder();
124.         return lHolder;
125.     }
126.  
127.     /**
128.      * @return
129.      */
130.     public LinearLayout getLastLineHolder() {
131.         if (lineViews.isEmpty()) {
132.             this.addNewLineHolder();
133.         }
134.         // 得到最后一行，计算其剩余宽度
135.         LinearLayout lHolder = lineViews.get(lineViews.size() – 1);
136.         return lHolder;
137.     }
138.  
139.     public void setOnItemClickListener(AdapterView.OnItemClickListener itemClickListener) {
140.         this.itemClickListener = itemClickListener;
141.     }
142.  
143.     public AdapterView.OnItemClickListener getItemClickListener() {
144.         return itemClickListener;
145.     }
146. }