导航栏Tools->"Android"->"Android Device Monitor"->File Explorer->mnt->sdcard
MainActivity.class:
privateStringfilename="test";
caseR.id.writBtn:
File myfile=newFile(sdcard,"this is my file.txt");
if(!sdcard.exists()){
Toast.makeText(getApplicationContext(),"当前设备不具备SD卡目录",Toast.LENGTH_LONG).show();
return;
}try{
myfile.createNewFile();
Toast.makeText(getApplicationContext(),"创建目录已完成",Toast.LENGTH_LONG).show();
FileOutputStream fos =newFileOutputStream(myfile);
OutputStreamWriter osw =newOutputStreamWriter(fos,"UTF-8");
osw.write(et.getText().toString());
osw.flush();
osw.close();
fos.close();
Toast.makeText(getApplicationContext(),"文件写入完成",Toast.LENGTH_LONG).show();
}catch(IOException e) {
e.printStackTrace();
}
break;
caseR.id.readBtn:
File myfiles=newFile(sdcard,"this is my file.txt");
if(myfiles.exists()) {
FileInputStream fis =null;
try{
fis =newFileInputStream(myfiles);
InputStreamReader isr =newInputStreamReader(fis,"UTF-8");
char[] input =new char[fis.available()];
isr.read(input);
isr.close();
fis.close();
String inString =newString(input);
show.setText(inString);
}catch(FileNotFoundException e) {
e.printStackTrace();
}catch(UnsupportedEncodingException e) {
e.printStackTrace();
}catch(IOException e) {
e.printStackTrace();
}
}
break;
注意在AndroidManifest.xml中 添加SD权限
完成效果图：
