[英]AsyncTask progress bar
我正在使用AsyncTask(第一次)在加密文件时显示进度条。 在尝试添加进度条之前,我的加密已起作用,但现在似乎使该应用程序崩溃。 我知道onPreExecute()可通过测试运行,所以我认为问题出在doInBackground()。 任何帮助将非常感激。
public class EncryptAsync extends AsyncTask<Void, Void, Void> {
//ProgressDialog progressDialog;
//declare other objects as per your need
@Override
protected void onPreExecute() {
// progressDialog = ProgressDialog.show(EncryptFile.this, "Progress Dialog Title Text", "Process Description Text", true);
if (password.getText().toString().equals(confirmPassword.getText().toString())) {
correctPassword = password.getText().toString();
//Toast.makeText(this,correctPassword,Toast.LENGTH_LONG).show();
//copies Plain Text to String
fileEditText.setInputType(InputType.TYPE_CLASS_TEXT);
returnFile = fileEditText.getText().toString();
Toast.makeText(EncryptFile.this, returnFile, Toast.LENGTH_LONG).show();
} else {
Toast.makeText(EncryptFile.this, "Passwords do not match", Toast.LENGTH_LONG).show();
}
}
@Override
protected Void doInBackground(Void... params) {
if (spinnerValue.equals("AES")) {
Toast.makeText(EncryptFile.this, returnFile, Toast.LENGTH_LONG).show();
try {
// Here you read the cleartext.
FileInputStream fis = new FileInputStream(returnFile);
// This stream write the encrypted text. This stream will be wrapped by another stream.
FileOutputStream fos = new FileOutputStream(returnFile + ".aes");
// hash password with SHA-256 and crop the output to 128-bit for key
MessageDigest digest = MessageDigest.getInstance("SHA-256");
digest.update(correctPassword.getBytes());
// copys hashed password to key
System.arraycopy(digest.digest(), 0, key, 0, key.length);
SecretKeySpec sks = new SecretKeySpec(key, "AES");
// Create cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, sks);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
} catch (Exception ex) {
Toast.makeText(EncryptFile.this, "Error with Exception", Toast.LENGTH_LONG).show();
} catch(Throwable t){
Toast.makeText(EncryptFile.this, "Error with throwable", Toast.LENGTH_LONG).show();
}
} else if (spinnerValue.equals("Blowfish")) {
//code for blowfish
}
return null;
}
@Override
protected void onPostExecute(Void result) {
Toast.makeText(EncryptFile.this, "Finished Encryption", Toast.LENGTH_LONG).show();
// super.onPostExecute(result);
// progressDialog.dismiss();
}
通过单击此按钮来调用
public void EncryptButton(View view) {
EncryptAsync task = new EncryptAsync();
task.execute();
}
您得到的异常很可能是NetworkOnMainThreadException之类的东西。
在AsyncTask中,不允许在doInBackground方法中对视图进行任何修改。 所有这些都应移至onPreExecute,onPostExecute或onUpdate。
至少这行违反了这一点:
Toast.makeText(EncryptFile.this, returnFile, Toast.LENGTH_LONG).show();
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