Code cleanups

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/CloneUidTool.java

@@ -79,7 +79,7 @@ protected void onCreate(Bundle savedInstanceState) {
  R.id.editTextCloneUidToolWriteKey);
  mStatusLogContent = findViewById(
  R.id.textViewCloneUidToolStatusLogContent);
- mShowOptions = (CheckBox) findViewById(
+ mShowOptions = findViewById(
  R.id.checkBoxCloneUidToolOptions);
  mRadioButtonKeyB = findViewById(
  R.id.radioButtonCloneUidToolKeyB);
@@ -390,7 +390,7 @@ private void appendToLog(String text) {
  * (in this case the "show options" check box).
  */
  public void onShowOptions(View view) {
- LinearLayout optionsLayout = (LinearLayout) findViewById(
+ LinearLayout optionsLayout = findViewById(
  R.id.linearLayoutOptions);
  if (mShowOptions.isChecked()) {
  optionsLayout.setVisibility(View.VISIBLE);

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/DumpEditor.java

@@ -436,9 +436,9 @@ private void saveFile(final String[] data, final String fileName,
  View dialogLayout = getLayoutInflater().inflate(
  R.layout.dialog_save_file,
  findViewById(android.R.id.content), false);
- TextView message = (TextView) dialogLayout.findViewById(
+ TextView message = dialogLayout.findViewById(
  R.id.textViewDialogSaveFileMessage);
- final EditText input = (EditText) dialogLayout.findViewById(
+ final EditText input = dialogLayout.findViewById(
  R.id.editTextDialogSaveFileName);
  message.setText(messageId);
  input.setText(fileName);
@@ -975,7 +975,7 @@ private void saveKeys() {
  if (mDumpName == null) {
  mKeysName = "UID_" + mUID;
  } else {
- mKeysName = new String(mDumpName);
+ mKeysName = mDumpName;
  }
  }
  mKeysName += ".keys";

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/FileChooser.java

@@ -332,9 +332,9 @@ private void onNewFile() {
  View dialogLayout = getLayoutInflater().inflate(
  R.layout.dialog_save_file,
  findViewById(android.R.id.content), false);
- TextView message = (TextView) dialogLayout.findViewById(
+ TextView message = dialogLayout.findViewById(
  R.id.textViewDialogSaveFileMessage);
- final EditText input = (EditText) dialogLayout.findViewById(
+ final EditText input = dialogLayout.findViewById(
  R.id.editTextDialogSaveFileName);
  message.setText(R.string.dialog_new_file);
  input.setText(prefill);
@@ -344,14 +344,9 @@ private void onNewFile() {
  // Show keyboard.
  InputMethodManager imm = (InputMethodManager) getSystemService(
  Context.INPUT_METHOD_SERVICE);
- input.postDelayed(new Runnable()
- {
- @Override
- public void run()
- {
- input.requestFocus();
- imm.showSoftInput(input, 0);
- }
+ input.postDelayed(() -> {
+ input.requestFocus();
+ imm.showSoftInput(input, 0);
  }, 100);
 
  // Ask user for filename.

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/IActivityThatReactsToSave.java

@@ -31,12 +31,12 @@ public interface IActivityThatReactsToSave {
  /**
  * This method will be called after a successful save process.
  */
- public abstract void onSaveSuccessful();
+ void onSaveSuccessful();
 
  /**
  * This method will be called, if there was an error during the
  * save process or it the user hits "cancel" in the "file already exists"
  * dialog.
  */
- public abstract void onSaveFailure();
+ void onSaveFailure();
 }

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/ImportExportTool.java

@@ -32,6 +32,8 @@
 import android.view.View;
 import android.widget.Toast;
 
+import androidx.annotation.NonNull;
+
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -97,6 +99,7 @@ private enum FileType {
  this.text = text;
  }
 
+ @NonNull
  @Override
  public String toString() {
  return text;
@@ -488,7 +491,7 @@ private void saveConvertedDataToContent(String[] convertedContent,
  Toast.LENGTH_LONG).show();
  return;
  }
- boolean success = false;
+ boolean success;
  if (mFileType != FileType.BIN) {
  success = Common.saveFile(contentDestination, convertedContent, this);
  } else {
@@ -551,7 +554,7 @@ private String[] convertDump(String[] source, FileType srcType,
  Common.isValidDumpErrorToast(err, this);
  return null;
  }
- int sectorNumber = 0;
+ int sectorNumber;
  int blockNumber = 0;
  for (String line : source) {
  if (line.startsWith("+")) {
@@ -624,7 +627,7 @@ private String[] convertDump(String[] source, FileType srcType,
  return null;
  }
 
- JSONObject blocks = null;
+ JSONObject blocks;
  try {
  JSONObject parsedJson = new JSONObject(TextUtils.join("", json));
  blocks = parsedJson.getJSONObject("blocks");
@@ -886,7 +889,7 @@ private boolean backupDumpsAndKeys(Uri contentDestUri) {
  file.getAbsolutePath().substring(commonPathLen));
  entry.setTime(file.lastModified());
  out.putNextEntry(entry);
- int count = 0;
+ int count;
  while ((count = origin.read(data, 0, BUFFER)) != -1) {
  out.write(data, 0, count);
  }

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/KeyEditor.java

@@ -312,9 +312,9 @@ private void onSave() {
  View dialogLayout = getLayoutInflater().inflate(
  R.layout.dialog_save_file,
  findViewById(android.R.id.content), false);
- TextView message = (TextView) dialogLayout.findViewById(
+ TextView message = dialogLayout.findViewById(
  R.id.textViewDialogSaveFileMessage);
- final EditText input = (EditText) dialogLayout.findViewById(
+ final EditText input = dialogLayout.findViewById(
  R.id.editTextDialogSaveFileName);
  message.setText(R.string.dialog_save_keys);
  input.setText(mFileName);

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/Preferences.java

@@ -31,6 +31,8 @@
 import android.widget.RadioGroup;
 import android.widget.Toast;
 
+import androidx.annotation.NonNull;
+
 import de.syss.MifareClassicTool.Common;
 import de.syss.MifareClassicTool.R;
 
@@ -62,6 +64,7 @@ public enum Preference {
  this.text = text;
  }
 
+ @NonNull
  @Override
  public String toString() {
  return text;
@@ -370,4 +373,4 @@ public void onSave(View view) {
  public void onCancel(View view) {
  finish();
  }
-}
+}

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/ReadTag.java

@@ -71,23 +71,21 @@ public void onCreate(Bundle savedInstanceState) {
  public void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
 
- switch(requestCode) {
- case KEY_MAP_CREATOR:
+ if (requestCode == KEY_MAP_CREATOR) {
  if (resultCode != Activity.RESULT_OK) {
  // Error.
  if (resultCode == 4) {
  // Error. Path from the calling intend was null.
  // (This is really strange and should not occur.)
  Toast.makeText(this, R.string.info_strange_error,
-  Toast.LENGTH_LONG).show();
+ Toast.LENGTH_LONG).show();
  }
  finish();
  return;
  } else {
  // Read Tag.
  readTag();
  }
- break;
  }
  }
 

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Activities/WriteTag.java

@@ -257,12 +257,10 @@ public void onActivityResult(int requestCode,
 
  // Error handling for the return value of KeyMapCreator.
  // So far, only error nr. 4 needs to be handled.
- switch (ckmError) {
- case 4:
- // Error. Path from the calling intend was null.
+ if (ckmError == 4) {// Error. Path from the calling intend was null.
  // (This is really strange and should not occur.)
  Toast.makeText(this, R.string.info_strange_error,
-  Toast.LENGTH_LONG).show();
+ Toast.LENGTH_LONG).show();
  }
  }
 
@@ -872,7 +870,7 @@ private void initDumpWithPosFromDump(String[] dump) {
  // with the static ones.
  String newBlock = dump[i].substring(0, 12)
  + mStaticAC.getText().toString()
- + dump[i].substring(18, dump[i].length());
+ + dump[i].substring(18);
  dump[i] = newBlock;
  }
  mDumpWithPos.get(sector).put(block++,

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/Common.java

@@ -275,7 +275,7 @@ public static String[] readFileLineByLine(File file, boolean readAll,
  if (file == null || !file.exists()) {
  return null;
  }
- String[] ret = null;
+ String[] ret;
  BufferedReader reader = null;
  try {
  reader = new BufferedReader(new FileReader(file));
@@ -306,8 +306,8 @@ public static String[] readFileLineByLine(File file, boolean readAll,
  * @see #readLineByLine(BufferedReader, boolean, Context)
  */
  public static String[] readUriLineByLine(Uri uri, boolean readAll, Context context) {
- InputStream contentStream = null;
- String[] ret = null;
+ InputStream contentStream;
+ String[] ret;
  if (uri == null || context == null) {
  return null;
  }
@@ -336,7 +336,7 @@ public static String[] readUriLineByLine(Uri uri, boolean readAll, Context conte
  * an read error.
  */
  public static byte[] readUriRaw(Uri uri, Context context) {
- InputStream contentStream = null;
+ InputStream contentStream;
  if (uri == null || context == null) {
  return null;
  }
@@ -372,7 +372,7 @@ public static byte[] readUriRaw(Uri uri, Context context) {
  */
  private static String[] readLineByLine(BufferedReader reader,
  boolean readAll, Context context) {
- String[] ret = null;
+ String[] ret;
  String line;
  ArrayList<String> linesArray = new ArrayList<>();
  try {
@@ -421,17 +421,14 @@ private static String[] readLineByLine(BufferedReader reader,
  public static String getFileName(Uri uri, Context context) {
  String result = null;
  if (uri.getScheme().equals("content")) {
- Cursor cursor = context.getContentResolver().query(
- uri, null, null, null, null);
- try {
+ try (Cursor cursor = context.getContentResolver().query(
+ uri, null, null, null, null)) {
  if (cursor != null && cursor.moveToFirst()) {
  int index = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
  if (index >= 0) {
  result = cursor.getString(index);
  }
  }
- } finally {
- cursor.close();
  }
  }
  if (result == null) {
@@ -580,7 +577,7 @@ public static boolean saveFile(File file, String[] lines, boolean append) {
  } else {
  error = true;
  }
- return error == false;
+ return !error;
  }
 
  /**
@@ -608,7 +605,7 @@ public static boolean saveFile(Uri contentUri, String[] lines, Context context)
  * @return True if file writing was successful. False otherwise.
  */
  public static boolean saveFile(Uri contentUri, byte[] bytes, Context context) {
- OutputStream output = null;
+ OutputStream output;
  if (contentUri == null || bytes == null || context == null || bytes.length == 0) {
  return false;
  }
@@ -906,18 +903,7 @@ public static int checkMifareClassicSupport(Tag tag, Context context) {
  // MIFARE Plus EV1 2K/4K SL1
  return -1;
  } else {
- if ((sak & 1) == 1) { // SAK bit 1 = 1?
- // MIFARE Mini
- return -1;
- } else {
- // MIFARE Classic 1k
- // MIFARE SmartMX 1k
- // MIFARE Plus S 2K SL1
- // MIFARE Plus X 2K SL1
- // MIFARE Plus SE 1K
- // MIFARE Plus EV1 2K/4K SL1
- return -1;
- }
+ return -1;
  }
  } else {
  // Some MIFARE tag, but not Classic or Classic compatible.
@@ -982,7 +968,6 @@ public static boolean openApp(Context context, String packageName) {
  * <li>-1 - Can not check because Android version is >= 8.</li>
  * </ul>
  */
- @SuppressWarnings("deprecation")
  public static int isExternalNfcServiceRunning(Context context) {
  // getRunningServices() is deprecated since Android 8.
  if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
@@ -1325,7 +1310,7 @@ public static byte[] acMatrixToACBytes(byte[][] acMatrix) {
  * @param hexString The string to check.
  * @param context The Context in which the Toast will be shown.
  * @return True if sting is hex an 16 Bytes long, False otherwise.
- * @see #isHex(String, Context) 
+ * @see #isHex(String, Context)
  */
  public static boolean isHexAnd16Byte(String hexString, Context context) {
  boolean isHex = isHex(hexString, context);
@@ -1375,14 +1360,12 @@ public static boolean isValueBlock(String hexString) {
  // For better reading (~ = invert operator):
  // if (b0=b8 and b0=~b4) and (b1=b9 and b9=~b5) ...
  // ... and (b12=b14 and b13=b15 and b12=~b13) then
- if ( (b[0] == b[8] && (byte)(b[0]^0xFF) == b[4]) &&
- (b[1] == b[9] && (byte)(b[1]^0xFF) == b[5]) &&
- (b[2] == b[10] && (byte)(b[2]^0xFF) == b[6]) &&
- (b[3] == b[11] && (byte)(b[3]^0xFF) == b[7]) &&
- (b[12] == b[14] && b[13] == b[15] &&
- (byte)(b[12]^0xFF) == b[13])) {
- return true;
- }
+ return (b[0] == b[8] && (byte) (b[0] ^ 0xFF) == b[4]) &&
+ (b[1] == b[9] && (byte) (b[1] ^ 0xFF) == b[5]) &&
+ (b[2] == b[10] && (byte) (b[2] ^ 0xFF) == b[6]) &&
+ (b[3] == b[11] && (byte) (b[3] ^ 0xFF) == b[7]) &&
+ (b[12] == b[14] && b[13] == b[15] &&
+ (byte) (b[12] ^ 0xFF) == b[13]);
  }
  return false;
  }
@@ -1634,7 +1617,7 @@ public static boolean isValidBlock0(String block0, int uidLen, int tagSize,
  // Byte3.
  if (valid && (uidLen == 7 || uidLen == 10)) {
  // The 3rd byte of a double/triple sized UID shall not be 0x88.
- valid = !block0.substring(4, 6).equals("88");
+ valid = !block0.startsWith("88", 4);
  }
  // ATQA.
  // Check if there is a special ATQA tied to MIFARE SmartMX or TNP3xxx.
@@ -1813,7 +1796,7 @@ public static String hex2Ascii(String hex) {
  return null;
  }
  byte[] bytes = hex2Bytes(hex);
- String ret = null;
+ String ret;
  // Replace non printable ASCII with ".".
  for(int i = 0; i < bytes.length; i++) {
  if (bytes[i] < (byte)0x20 || bytes[i] == (byte)0x7F) {

Mifare Classic Tool/app/src/main/java/de/syss/MifareClassicTool/MCReader.java

@@ -21,7 +21,6 @@
 import android.content.Context;
 import android.nfc.Tag;
 import android.nfc.TagLostException;
-import android.nfc.tech.IsoDep;
 import android.nfc.tech.MifareClassic;
 import android.nfc.tech.NfcA;
 import android.os.Bundle;
@@ -31,8 +30,6 @@
 import android.util.SparseArray;
 import android.widget.Toast;
 
-import androidx.core.content.res.TypedArrayUtils;
-
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;