Android SD卡内的文件读写操作，androidsd卡内读写

Android SD卡内的文件读写操作，androidsd卡内读写

Android 读写SD卡内的文件操作

1.读文件

private String readFromFile(Context context){
		
		
		if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
			
			String foldername = Environment.getExternalStorageDirectory().getPath()+ "/eryaApp";
		    File folder = new File(foldername);
		    
		    if (folder == null || !folder.exists()) {
		    	folder.mkdir();
		    }
		    
		    File targetFile=new File("/sdcard/eryaApp/eryaShoppingList.txt");
		    String readedStr="";
		    
			 try{
				if(!targetFile.exists()){
					targetFile.createNewFile();
					return "No File error ";
				}else{
					 InputStream in = new BufferedInputStream(new FileInputStream(targetFile));
					 BufferedReader br= new BufferedReader(new InputStreamReader(in, "UTF-8"));
					 String tmp;
					 
					 while((tmp=br.readLine())!=null){
						 readedStr+=tmp;
					 }
					 br.close();
					 in.close();
					 
					 return readedStr;
				}
			 } catch (Exception e) {
					Toast.makeText(context,e.toString(),Toast.LENGTH_LONG).show();
					return e.toString();
			 }
		}else{
			Toast.makeText(context,"未发现SD卡！",Toast.LENGTH_LONG).show();
			return "SD Card error";
		}
		
	}

2.写文件

private void SavedToText(Context context,String stringToWrite){
		
		if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
			
			String foldername = Environment.getExternalStorageDirectory().getPath()+ "/eryaApp";
		    File folder = new File(foldername);
		    
		    if (folder == null || !folder.exists()) {
		    	folder.mkdir();
		    }
		    
		    String fileName="/eryaShoppingList"+".txt";
			
			File targetFile = new File(foldername + fileName);
			OutputStreamWriter osw;
	        
			 try{
				if(!targetFile.exists()){
					targetFile.createNewFile();
					osw = new OutputStreamWriter(new FileOutputStream(targetFile),"utf-8");
					osw.write(stringToWrite);  
					osw.close();
				}else{
					osw = new OutputStreamWriter(new FileOutputStream(targetFile,true),"utf-8");
					osw.write("\n"+stringToWrite);
					osw.flush();
					osw.close();
				}
			 } catch (Exception e) {
				Toast.makeText(context,e.toString(),Toast.LENGTH_LONG).show();
			 }
		}else{
			Toast.makeText(context,"未发现SD卡！",Toast.LENGTH_LONG).show();
		}
		
		 
	    
	  }