使用SharedPreferences将姓名和年龄信息保存到文件，然后再读取

main xml

java

定义

private EditText ev_userName;
private EditText password;
private Button write;
private Button read;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ev_userName = (EditText) findViewById(R.id.ev_userName);
password = (EditText) findViewById(R.id.ev_password);
write = (Button) findViewById(R.id.btn_login);
read = (Button) findViewById(R.id.btn_login2);

写入

write.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String Name = ev_userName.getText().toString();
String age = password.getText().toString();
if (saveToFile(Name)) {
Toast.makeText(MainActivity.this, "保存成功", Toast.LENGTH_SHORT).show();

}
}
});

读取

read.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String filename = "data.txt";
String result = "";
String uesrName;
try {
FileInputStream in = openFileInput(filename);
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
uesrName= reader.readLine();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (java.io.IOException e) {
e.printStackTrace();
}
uesrName = ev_userName.getText().toString();
String age = password.getText().toString();
Toast.makeText(MainActivity.this, "输入姓名" + uesrName + ",年龄：" + age, Toast.LENGTH_SHORT).show();
}
});
}

存储

private boolean saveToFile(String userName) {
//1.打开文件
try {
FileOutputStream out = openFileOutput("data.txt", MODE_PRIVATE );
//2.写入
BufferedWriter writer = new BufferedWriter( new OutputStreamWriter(out));
writer.write(userName);
//3.关闭文件输入流
out.close();
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}

}