// 向sd卡写入数据
private void writesdcard(string str) {
try {
// 判断是否存在sd卡
if (environment.getexternalstoragestate().equals(
environment.media_mounted)) {
// 获取sd卡的目录
file sddire = environment.getexternalstoragedirectory();
fileoutputstream outfilestream = new fileoutputstream(
sddire.getcanonicalpath() + "/test.txt");
outfilestream.write(str.getbytes());
outfilestream.close();
toast.maketext(this, "数据保存到text.txt文件了", toast.length_long)
.show();
}
} catch (exception e) {
e.printstacktrace();
}
}
// 从sd卡中读取数据
private void readsdcard() {
stringbuffer strsbuffer = new stringbuffer();
// 判断是否存在sd
file file = new file(environment.getexternalstoragedirectory()
.getcanonicalpath() + "/test.txt");
// 判断是否存在该文件
if (file.exists()) {
// 打开文件输入流
fileinputstream filer = new fileinputstream(file);
bufferedreader reads = new bufferedreader(
new inputstreamreader(filer));
string st = null;
while ((st = reads.readline()) != null) {
strsbuffer.append(st);
}
filer.close();
} else {
toast.maketext(this, "该目录下文件不存在", toast.length_long).show();
}
toast.maketext(this, "读取到的数据是：" + strsbuffer.tostring() + "",
toast.length_long).show();
}
转载：http://blog.csdn.net/chaoyu168/article/details/50721480