Android写文件到Sd卡的一般过程

注意权限：在mainfest添加WRITE权限！

package com.example.writesdcard;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

	
		
		

	    

		@Override  
	    protected void onCreate(Bundle savedInstanceState) {  
	        super.onCreate(savedInstanceState);  
	  
	        // 首先判断设备是否挂载SDCard  
	        boolean isMounted = Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);  
	  
	        if (isMounted) {  
	            try {  
	               
					writeFileToSDCard("强哥","你妹.txt");  
	            } catch (IOException e) {  
	                e.printStackTrace();  
	            }  
	        } else {  
	            Log.d("SDCard错误", "未安装SDCard！");  
	        }  
	    }  
	  
	   
	    private void writeFileToSDCard(String path,String name) throws IOException {  
	      
	        File parent_path = Environment.getExternalStorageDirectory();  
	  
	        // 可以建立一个子目录专门存放自己专属文件  
	        File dir = new File(parent_path.getAbsoluteFile(),path);  
	        dir.mkdir();  
	  
	        File file = new File(dir.getAbsoluteFile(), name);  
	  
	        Log.d("文件路径", file.getAbsolutePath());  
	  
	        // 创建这个文件，如果不存在  
	        file.createNewFile();  
	  
	        FileOutputStream fos = new FileOutputStream(file);  
	  
	        String data = "hello,world! IT @ CSDN";  
	        byte[] buffer = data.getBytes();  
	  
	        // 开始写入数据到这个文件。  
	        fos.write(buffer, 0, buffer.length);  
	        fos.flush();  
	        fos.close();  
	  
	        Log.d("文件写入", "成功");  
	    }  
		
		
	

	
}