android applications for specific types of files both locallyoptimal method

 Just because there is a demand

projects , the demand for mobile applications have the following two local files

 

first one is to specify the directory to be searched , and the second is the file type , such as "*. jpg; *. png ; *. gif".

 

queries from the data obtained with a variety of methods , there are two main kind is a direct query , another way is to use the broadcast way .

 

  
1. broadcasts
 

 

notification system through a proactive approach we need to file list, send a broadcast to your system

 

  

sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://" 
+ Environment.getExternalStorageDirectory())));

 

 

then access the system through the receiver text list

 

  

public class MediaScannerReceiver extends BroadcastReceiver 
{ 
    private final static String TAG = "MediaScannerReceiver"; 
    @Override 
    public void onReceive(Context context, Intent intent) { 
        String action = intent.getAction(); 
        Uri uri = intent.getData(); 
        String externalStoragePath = Environment.getExternalStorageDirectory().getPath(); 
        if (action.equals(Intent.ACTION_BOOT_COMPLETED)) { 
            // scan internal storage 
            scan(context, MediaProvider.INTERNAL_VOLUME); 
        } else { 
            if (uri.getScheme().equals("file")) { 
                // handle intents related to external storage 
                String path = uri.getPath(); 
                if (action.equals(Intent.ACTION_MEDIA_MOUNTED) && 
                        externalStoragePath.equals(path)) { 
                    scan(context, MediaProvider.EXTERNAL_VOLUME); 
                } else if (action.equals(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE) && 
                        path != null && path.startsWith(externalStoragePath + "/")) { 
                    scanFile(context, path); 
                } 
            } 
        } 
    } 
    private void scan(Context context, String volume) { 
        Bundle args = new Bundle(); 
        args.putString("volume", volume); 
        context.startService( 
                new Intent(context, MediaScannerService.class).putExtras(args)); 
    } 
    private void scanFile(Context context, String path) { 
        Bundle args = new Bundle(); 
        args.putString("filepath", path); 
        context.startService( 
                new Intent(context, MediaScannerService.class).putExtras(args)); 
    } 
}

 

 

  

注意部分： 
 
通过 Intent.ACTION_MEDIA_MOUNTED 进行全扫描 
 
通过 Intent.ACTION_MEDIA_SCANNER_SCAN_FILE 扫描某个文件 
 
上述方法是不支持对文件夹的 即：Uri data 必须是 文件的Uri  如果是文件夹的 其不会起作用的 切记！ 
 
方法二 直接查找 
      这种方法是最原始的方法，通过获取文件目录递归来查询文件 
       正面是主要实现： 
/** 
 
* 获取指定位置的指定类型的文件 
 
* 
 
* @param path 
 
*            文件夹路径 
 
* @param type 
 
*            文件类型（如"*.jpg;*.png;*.gif"） 
 
* @return 
 
*/ 
 
public static void getFileList(String path, String type, 
 
final OnFileListCallback onFileListCallback) { 
 
  
 
new AsyncTask<String, String, String>() { 
 
ArrayList<FileInfo> list = new ArrayList<FileInfo>(); 
 
@Override 
 
protected void onPostExecute(String result) { 
 
onFileListCallback.SearchFileListInfo(list); 
 
} 
 
  
 
@Override 
 
protected String doInBackground(String… params) { 
 
// TODO Auto-generated method stub 
 
  
 
String path = params[1].substring(params[1] 
 
.lastIndexOf(".") + 1); 
 
File file = new File(params[0]); 
 
scanSDCard(file,path,list); 
 
return null; 
 
} 
 
  
 
}.execute(path, type, ""); 
 
} 
 
  
 
/** 
 
* 扫描完成后的回调，获取文件列表必须实现 
 
* 
 
* @author cola 
 
* 
 
*/ 
 
public interface OnFileListCallback { 
 
/** 
 
* 返回查询的文件列表 
 
* @param list 文件列表 
 
*/ 
 
public void SearchFileListInfo(List<FileInfo> list); 
 
} 
 
  
 
private static void scanSDCard(File file, String ext, ArrayList<FileInfo> list) { 
 
if (file.isDirectory()) { 
 
File[] files = file.listFiles(); 
 
if (files != null) { 
 
for (int i = 0; i < files.length; i++) { 
 
File tmp = files[i]; 
 
if (tmp.isFile()) { 
 
String fileName = tmp.getName(); 
 
String filePath = tmp.getName(); 
 
if (fileName.indexOf(".") >= 0) { 
 
fileName = fileName.substring(fileName 
 
.lastIndexOf(".") + 1); 
 
if (ext != null && ext.equalsIgnoreCase(fileName)) { 
 
AspLog.i(TAG, filePath); 
 
FileInfo info = new FileInfo(); 
 
info.fileName = filePath; 
 
info.filePath = tmp.getAbsolutePath(); 
 
list.add(info); 
 
} 
 
} 
 
} else 
 
scanSDCard(tmp, ext, list); 
 
} 
 
} 
 
} else { 
 
if (file.isFile()) { 
 
String fileName = file.getName(); 
 
String filePath = file.getName(); 
 
if (fileName.indexOf(".") >= 0) { 
 
fileName = fileName 
 
.substring(fileName.lastIndexOf(".") + 1); 
 
if (ext != null && ext.equalsIgnoreCase(fileName)) { 
 
AspLog.i(TAG, filePath); 
 
FileInfo info = new FileInfo(); 
 
info.fileName = filePath; 
 
info.filePath = file.getAbsolutePath(); 
 
list.add(info); 
 
} 
 
} 
 
} 
 
} 
 
}

 

 

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