我正在使用文件编写器在我的应用程序中保存敏感的用户详细信息,该文件被保存到指定的目的地。我想在 ListView 中显示另一个类中保存的信息,我该如何将信息显示到 ListView 中,最好的方法是什么?。
任何人都可以建议任何方法来解决这个问题
保存信息的 Activity
public class PasswordKeeperActivity extends Activity implements
AdapterView.OnItemSelectedListener {
// initialise
EditText username, password, note;
Button save, reset;
public String savedata = Environment.getExternalStorageDirectory().toString();
String[] countryNames={"Google", "Yahoo", "Facebook", "Twitter", "Instagram", "BBM", "Skype", "Other"};
int flags[] = {R.drawable.google, R.drawable.yahoo, R.drawable.facebook, R.drawable.twitter, R.drawable.instagram, R.drawable.bbm, R.drawable.skype, R.drawable.other};
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
};
// for inflating the menu
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
// on selection of the menu
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.view_passwords:
Intent intent = new Intent(this, PasswordView.class);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
// An item was selected. You can retrieve the selected item using
// parent.getItemAtPosition(pos)
}
public void onNothingSelected(AdapterView<?> parent) {
// Another interface callback
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
initialise();
//Getting the instance of Spinner and applying OnItemSelectedListener on
it
Spinner spin = (Spinner) findViewById(R.id.planets_spinner);
spin.setOnItemSelectedListener(this);
CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(),
flags, countryNames);
spin.setAdapter(customAdapter);
//to set the site Edit Text to get the focus
// save the data to the textfile
save.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// creates hidden directory if not existing
File dir = new File(getCacheDir(), "/sk/");
if (!dir.exists()) {
dir.mkdirs();
}
// saving data part
String sFileName = getCacheDir() + "/sk/logp.csv";
try {
FileWriter writer = new FileWriter(sFileName, true);
String countryNames, sUser, sPass, sAdd;
countryNames =
sUser = username.getText().toString();
sPass = password.getText().toString();
sAdd = note.getText().toString();
if ((sUser.equals("")) && (sPass.equals("")) &&
(sAdd.equals(""))) {
Toast.makeText(getBaseContext(), "Please Enter At least
one Field",
Toast.LENGTH_SHORT).show();
} else {
if (sUser.equals(""))
sUser = "null";
if (sPass.equals(""))
sPass = "null";
if (sAdd.equals(""))
sAdd = "null";
// encrypting the passwords before saving
SimpleCrypto mcrypt = new SimpleCrypto();
sPass = SimpleCrypto.bytesToHex( mcrypt.encrypt(sPass) );
//sPass = SimpleCrypto.encrypt("fugly", sPass);
writer.append(sUser);
writer.append(',');
writer.append(sPass);
writer.append(',');
writer.append(sAdd);
writer.append('\n');
// generate whatever data you want
writer.flush();
writer.close();
Toast.makeText(getBaseContext(), "Password Saved!",
Toast.LENGTH_SHORT).show();
Intent intent = new Intent(PasswordKeeperActivity.this,
PasswordView.class);
String[] myStrings = new String[] {"Google", "Yahoo",
"Facebook", "Twitter", "Instagram", "BBM", "Skype", "Other"};
int logo[] = new int[] {R.drawable.google,
R.drawable.yahoo, R.drawable.facebook, R.drawable.twitter,
R.drawable.instagram,
R.drawable.bbm, R.drawable.skype, R.drawable.other};
intent.putExtra("strings", myStrings);
intent.putExtra("logos", logo);
startActivity(intent);
}
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(),
Toast.LENGTH_SHORT).show();
}
}
});
// Reset
reset.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
countryNames.equals("Google");
note.setText("");
username.setText("");
password.setText("");
Toast.makeText(getBaseContext(), "Field(s) Cleared!",
Toast.LENGTH_SHORT).show();
}
});
}
public void initialise() {
username = (EditText) findViewById(R.id.input_name);
password = (EditText) findViewById(R.id.input_email);
note = (EditText) findViewById(R.id.input_password);
save = (Button) findViewById(R.id.buttonSave);
reset = (Button) findViewById(R.id.ButtonReset);
}
/**
* Checks if the app has permission to write to device storage
*
* If the app does not has permission then the user will be prompted to
grant permissions
*
* @param activity
*/
public static void verifyStoragePermissions(Activity activity) {
// Check if we have write permission
int permission = ActivityCompat.checkSelfPermission(activity,
Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (permission != PackageManager.PERMISSION_GRANTED) {
// We don't have permission so prompt the user
ActivityCompat.requestPermissions(
activity,
PERMISSIONS_STORAGE,
REQUEST_EXTERNAL_STORAGE
);
}
}
}
最佳答案
使用 FileReader 检索文件。您应该使用一个单独的类来存储使用 FileWriter 和 FileReader 加载和保存文件的方法。从那里,您可以向该类添加引用对象,并在需要时使用整个项目的方法来加载和保存数据。
下面是如何使用 FileReader 从文件中检索数据的示例。
File file = new File("Hello.txt");
FileReader fr = new FileReader(file);
char[]a = new char[100];
for(char c : a) {
System.out.println(c);
}
fr.close();
关于java - 如何在 ListView 中显示使用文件写入器保存的项目,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45695005/