Android开发之GridView的Item放大缩小

ゝ一纸荒年。 2022-08-02 01:55 417阅读 0赞

为了弄GridView中Item的放大缩小，弄了好久，纠结了好久，也找了好多资料，终于弄出来了。

一、效果图如下：

![gridview中item的放大缩小][gridview_item]

二、GridView实现九宫格比较容易，难的是实现动画放大和放大后不会被后面的Item覆盖的问题，有人说用View.Bringtofornt()可以解决，不过我试了好久都不行，可能我的方法不对，有高手使用View.Bringtofornt()实现成功的可以交流一下。我用的是另一种方法：继承GridView，实现protected int getChildDrawingOrder(int childCount, int i)方法。代码如下：MyGridView.java

**\[java\]**  [view plain][] [copy][view plain] [print][view plain] [?][view plain]

1.  **package** com.src;  
2.    
3.  **import** android.annotation.SuppressLint;  
4.  **import** android.content.Context;  
5.  **import** android.util.AttributeSet;  
6.  **import** android.widget.GridView;  
7.    
8.  **public** **class** MyGridView **extends** GridView \{  
9.    
10.     **private** **int** position = 0;  
11.   
12.     **public** MyGridView(Context context) \{  
13.         **super**(context);  
14.     \}  
15.   
16.     **public** MyGridView(Context context, AttributeSet attrs) \{  
17.         **super**(context, attrs);  
18.         setChildrenDrawingOrderEnabled(**true**);  
19.     \}  
20.   
21.     **public** **void** setCurrentPosition(**int** pos) \{  
22.         // 刷新adapter前，在activity中调用这句传入当前选中的item在屏幕中的次序  
23.         **this**.position = pos;  
24.     \}  
25.   
26.     @SuppressLint("NewApi")  
27.     @Override  
28.     **protected** **void** setChildrenDrawingOrderEnabled(**boolean** enabled) \{  
29.         // TODO Auto-generated method stub  
30.         **super**.setChildrenDrawingOrderEnabled(enabled);  
31.     \}  
32.   
33.     @Override  
34.     **protected** **int** getChildDrawingOrder(**int** childCount, **int** i) \{  
35.         **if** (i == childCount - 1) \{ // 这是最后一个需要刷新的item  
36.             **return** position;  
37.         \}  
38.         **if** (i == position) \{ // 这是原本要在最后一个刷新的item  
39.             **return** childCount - 1;  
40.         \}  
41.         **return** i;// 正常次序的item  
42.     \}  
43.   
44. \}

三、然后在XML中使用重写的GridView定义控件：main.xml

**\[html\]**  [view plain][] [copy][view plain] [print][view plain] [?][view plain]

1.  **<?****xml** version="1.0" encoding="utf-8"**?>**  
2.  **<****LinearLayout** xmlns:android="http://schemas.android.com/apk/res/android"  
3.      android:layout\_width="match\_parent"  
4.      android:layout\_height="match\_parent"  
5.      android:gravity="center\_horizontal"  
6.      android:orientation="vertical" **>**  
7.    
8.      **<****LinearLayout**  
9.          android:layout\_width="600dip"  
10.         android:layout\_height="wrap\_content"  
11.         android:orientation="vertical" **>**  
12.   
13.         **<****com.src.MyGridView**  
14.             android:id="@+id/gridview"  
15.             android:layout\_width="match\_parent"  
16.             android:layout\_height="match\_parent"  
17.             android:background="\#ffffff"  
18.             android:focusable="true"  
19.             android:gravity="center"  
20.             android:horizontalSpacing="1.0dip"  
21.             android:listSelector="@android:color/transparent"  
22.             android:numColumns="5"  
23.             android:stretchMode="spacingWidthUniform"  
24.             android:unselectedAlpha="0.2"  
25.             android:verticalSpacing="1.0dip" **/>**  
26.     **</****LinearLayout****>**  
27.   
28. **</****LinearLayout****>**

四、然后重写适配器继承BaseAdapter：ImageAdapter.java

**\[java\]**  [view plain][] [copy][view plain] [print][view plain] [?][view plain]

1.  **package** com.src;  
2.    
3.  **import** java.util.ArrayList;  
4.  **import** java.util.HashMap;  
5.    
6.  **import** android.content.Context;  
7.  **import** android.view.LayoutInflater;  
8.  **import** android.view.View;  
9.  **import** android.view.ViewGroup;  
10. **import** android.widget.BaseAdapter;  
11. **import** android.widget.GridView;  
12. **import** android.widget.ImageView;  
13. **import** android.widget.TextView;  
14.   
15. **public** **class** ImageAdapter **extends** BaseAdapter \{  
16.     **private** ArrayList<HashMap<String, String>> list = **null**;  
17.     **private** **int** isSelect = -1;  
18.     **private** **int** isClick = -1;  
19.     **private** Context context;  
20.   
21.     **public** ImageAdapter(Context context, ArrayList<HashMap<String, String>> list) \{  
22.         **this**.list = list;  
23.         **this**.context = context;  
24.     \}  
25.   
26.     **public** **int** getCount() \{  
27.         // TODO Auto-generated method stub  
28.         **return** list.size();  
29.     \}  
30.   
31.     **public** Object getItem(**int** position) \{  
32.         // TODO Auto-generated method stub  
33.         **return** list.get(position);  
34.     \}  
35.   
36.     **public** **long** getItemId(**int** position) \{  
37.         // TODO Auto-generated method stub  
38.         **return** position;  
39.     \}  
40.   
41.     **public** **void** setNotifyDataChange(**int** id) \{  
42.         isSelect = id;  
43.         **super**.notifyDataSetChanged();  
44.     \}  
45.   
46.     **public** **void** setNotifyItemSelected(**int** id) \{  
47.         isClick = id;  
48.         **super**.notifyDataSetChanged();  
49.     \}  
50.   
51.     **public** View getView(**int** position, View convertView, ViewGroup parent) \{  
52.         // TODO Auto-generated method stub  
53.         ViewHolder holder = **new** ViewHolder();  
54.         **if** (convertView == **null**) \{  
55.             convertView = LayoutInflater.from(context).inflate(  
56.                     R.layout.gridview\_item, **null**);  
57.             holder.mImageView = (ImageView) convertView.findViewById(R.id.img);  
58.             holder.mTextView = (TextView) convertView.findViewById(R.id.text);  
59.   
60.             convertView.setTag(holder);  
61.         \} **else** \{  
62.             holder = (ViewHolder) convertView.getTag();  
63.         \}  
64.   
65.         holder.mImageView.setImageResource(R.drawable.icon);  
66.         String name = list.get(position).get("name");  
67.         holder.mTextView.setText(name);  
68.         convertView.setLayoutParams(**new** GridView.LayoutParams(150, 210));  
69.   
70.         **if** (isClick == position) \{  
71.             holder.mImageView.setBackgroundResource(R.drawable.gvitemselect2);  
72.         \} **else** \{  
73.             **if** (isSelect == position) \{  
74.                 holder.mImageView  
75.                         .setBackgroundResource(R.drawable.gvitemselect1);  
76.             \} **else** \{  
77.                 holder.mImageView  
78.                         .setBackgroundResource(R.drawable.gvitemselect);  
79.             \}  
80.         \}  
81.   
82.         **return** convertView;  
83.   
84.     \}  
85.   
86.     **class** ViewHolder \{  
87.         **public** ImageView mImageView = **null**;  
88.         **public** TextView mTextView = **null**;  
89.     \}  
90.   
91. \}

五、在Activity中监听GridView事件实现放大缩小：GrideActivity.java

**\[java\]**  [view plain][] [copy][view plain] [print][view plain] [?][view plain]

1.  **package** com.src;  
2.    
3.  **import** java.util.ArrayList;  
4.  **import** java.util.HashMap;  
5.    
6.  **import** android.app.Activity;  
7.  **import** android.os.Bundle;  
8.  **import** android.view.View;  
9.  **import** android.view.animation.Animation;  
10. **import** android.view.animation.AnimationSet;  
11. **import** android.view.animation.ScaleAnimation;  
12. **import** android.widget.AdapterView;  
13. **import** android.widget.AdapterView.OnItemClickListener;  
14. **import** android.widget.AdapterView.OnItemSelectedListener;  
15.   
16. **public** **class** GrideActivity **extends** Activity **implements** OnItemClickListener,  
17.         OnItemSelectedListener \{  
18.     **private** ArrayList<HashMap<String, String>> itemList = **null**;  
19.     **private** ImageAdapter adapterItem = **null**;  
20.     **private** MyGridView gridview = **null**;  
21.   
22.     **private** AnimationSet manimationSet;  
23.   
24.     ScaleAnimation scaleAnimation = **new** ScaleAnimation(1.7f, 0.8f, 1.7f, 0.8f,  
25.             Animation.RELATIVE\_TO\_SELF, 0.5f, Animation.RELATIVE\_TO\_SELF, 0.5f);  
26.     ScaleAnimation scaleAnimation1 = **new** ScaleAnimation(1, 1.7f, 1, 1.7f,  
27.             Animation.RELATIVE\_TO\_SELF, 0.5f, Animation.RELATIVE\_TO\_SELF, 0.5f);  
28.   
29.     @Override  
30.     **protected** **void** onCreate(Bundle savedInstanceState) \{  
31.         // TODO Auto-generated method stub  
32.         **super**.onCreate(savedInstanceState);  
33.         setContentView(R.layout.main);  
34.   
35.         itemList = **new** ArrayList<HashMap<String, String>>();  
36.         **for** (**int** i = 0; i < 10; i++) \{  
37.             HashMap<String, String> map = **new** HashMap<String, String>();  
38.             map.put("name", i + " item");  
39.             itemList.add(map);  
40.         \}  
41.   
42.         adapterItem = **new** ImageAdapter(**this**, itemList);  
43.         gridview = (MyGridView) findViewById(R.id.gridview);  
44.         gridview.setAdapter(adapterItem);  
45.         gridview.setOnItemClickListener(**this**);  
46.         gridview.setOnItemSelectedListener(**this**);  
47.         gridview.smoothScrollToPosition(2);  
48.   
49.     \}  
50.   
51.     /\*\* 
52.      \* 播放动画 
53.      \*  
54.      \* @param view 
55.      \*/  
56.     **private** **void** startAnimation(View view) \{  
57.         AnimationSet animationSet = **new** AnimationSet(**true**);  
58.         **if** (manimationSet != **null** && manimationSet != animationSet) \{  
59.   
60.             scaleAnimation.setDuration(500);  
61.             manimationSet.addAnimation(scaleAnimation);  
62.             manimationSet.setFillAfter(**false**);  
63.             view.startAnimation(manimationSet);  
64.         \}  
65.         scaleAnimation1.setDuration(500);  
66.         animationSet.addAnimation(scaleAnimation1);  
67.         animationSet.setFillAfter(**true**);  
68.         view.startAnimation(animationSet);  
69.         manimationSet = animationSet;  
70.   
71.     \}  
72.   
73.     /\*\* 
74.      \* 点击选中 
75.      \*/  
76.     **public** **void** onItemClick(AdapterView<?> parent, View view, **int** position,  
77.             **long** id) \{  
78.         // TODO Auto-generated method stub  
79.         startAnimation(view);  
80.         gridview.setCurrentPosition(position);  
81.         adapterItem.setNotifyItemSelected(position);  
82.     \}  
83.   
84.     /\*\* 
85.      \* 移动焦点 
86.      \*/  
87.     **public** **void** onItemSelected(AdapterView<?> parent, View view, **int** position,  
88.             **long** id) \{  
89.         // TODO Auto-generated method stub  
90.         startAnimation(view);  
91.         gridview.setCurrentPosition(position);  
92.         adapterItem.setNotifyDataChange(position);  
93.   
94.     \}  
95.   
96.     **public** **void** onNothingSelected(AdapterView<?> parent) \{  
97.         // TODO Auto-generated method stub  
98.   
99.     \}  
100.   
101. \}

项目源代码下载： [http://download.csdn.net/detail/gaosunqiong/7937217][http_download.csdn.net_detail_gaosunqiong_7937217]

[gridview_item]: /images/20220731/ce399449865b42f29afcdd157ed6b3d5.png
[view plain]: http://blog.csdn.net/gaosunqiong/article/details/39371401#
[http_download.csdn.net_detail_gaosunqiong_7937217]: http://download.csdn.net/detail/gaosunqiong/7937217