android中把文件保存到sdcard代码实例

直接上代码：

package com.example.test;

import java.io.file;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;

import android.os.bundle;
import android.os.environment;
import android.app.activity;
import android.widget.toast;

public class mainactivity extends activity {
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
    
    //要保存的文件名和文件内容
    string filename = "test.txt";
    string content = "this is a test.";
    
    //判断sdcard是否存在
    string state = environment.getexternalstoragestate();
    if(state.equals(environment.media_mounted)) {
     //获取sdcard目录
     file sdcardpath = environment.getexternalstoragedirectory();
     
     file file = new file(sdcardpath, filename);
     fileoutputstream fos;
  try {
  fos = new fileoutputstream(file);
  fos.write(content.getbytes());
  fos.close();
  } catch (filenotfoundexception e) {
  e.printstacktrace();
  } catch (ioexception e) {
  e.printstacktrace();
  }
  toast.maketext(this, "保存成功", toast.length_short).show();
    } else {
     toast.maketext(this, "sdcard不存在获取不可写入", toast.length_short).show();
    }
    
  }
}