1 import java.io.File;
 2 
 3 import android.content.Context;
 4 import android.os.Environment;
 5 import android.os.StatFs;
 6 
 7 public class CommonUtil {
 8 
 9     /**
10      * 检测sdcard是否可用
11      * 
12      * @return true为可用，否则为不可用
13      */
14     public static boolean sdCardIsAvailable() {
15         String status = Environment.getExternalStorageState();
16         if (!status.equals(Environment.MEDIA_MOUNTED))
17             return false;
18         return true;
19     }
20 
21     /**
22      * 检测内存上的剩余空间够不够用，以及是否可用
23      */
24     public static boolean enoughSpaceOnSdCard(long downloadSize) {
25         String status = Environment.getExternalStorageState();
26         if (!status.equals(Environment.MEDIA_MOUNTED))
27             return false;
28         return (downloadSize < getRealSizeOnSdcard());
29     }
30 
31     /**
32      * 获得SD卡上的剩余空间
33      */
34     public static long getRealSizeOnSdcard() {
35         File path = new File(Environment.getExternalStorageDirectory().getAbsolutePath());
36         StatFs stat = new StatFs(path.getPath());
37         long blockSize = stat.getBlockSize();
38         long availableBlocks = stat.getAvailableBlocks();
39         return availableBlocks * blockSize;
40     }
41 
42     /**
43      * 检查机身内存是否够用
44      */
45     public static boolean enoughSpaceOnPhone(long downloadSize) {
46         return getRealSizeOnPhone() > downloadSize;
47     }
48 
49     /**
50      * 获得机身剩余内存
51      */
52     public static long getRealSizeOnPhone() {
53         File path = Environment.getDataDirectory();
54         StatFs stat = new StatFs(path.getPath());
55         long blockSize = stat.getBlockSize();
56         long availableBlocks = stat.getAvailableBlocks();
57         long realSize = blockSize * availableBlocks;
58         return realSize;
59     }
60     
61     /**
62      * 根据手机分辨率从dp转成px
63      */
64     public static  int dip2px(Context context, float dpValue) {  
65         final float scale = context.getResources().getDisplayMetrics().density;  
66         return (int) (dpValue * scale + 0.5f);  
67     }  
68       
69     /** 
70      * 根据手机的分辨率从 px(像素) 的单位 转成为 dp 
71      */  
72     public static  int px2dip(Context context, float pxValue) {  
73         final float scale = context.getResources().getDisplayMetrics().density;  
74         return (int) (pxValue / scale + 0.5f)-15;  
75     }  
76 
77     
78 }