Table des matières
Le Tutoriel de Android TextWatcher
View more Tutorials:
Comme vous le savez, TextEdit permet à l'utilisateur d'entrer et de modifier le texte. TextEdit utilise l'interface TextWatcher pour afficher les changements survenus à ses textes, ou pour modifier le contenu du texte.
editText.addTextChangedListener(TextWatcher watcher)editText.addTextChangedListener(TextWatcher watcher)
Les méthodes de l'interface TextWatcher sont:
- void afterTextChanged(Editable s)
- void beforeTextChanged(CharSequence s, int start, int count, int after)
- void onTextChanged(CharSequence s, int start, int before, int count)
TextWatcher est utilisé pour s'assurer que l'utilisateur entre un texte correspondant à un modèle (pattern) donné.
Dans l'exemple ci-dessous, on utilise TextWatcher pour s'assurer que l'utilisateur entre une date valide au format DD/MM/YYYY.
DateFormatTextWatcher.java
package org.o7planning.textwatcherdateexample;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import java.util.Calendar;
public class DateFormatTextWatcher implements TextWatcher {
private static final String DDMMYYYY = "DDMMYYYY";
private static final String SEPARATOR = "/";
private final Calendar calendar = Calendar.getInstance();
private String currentText = "";
private EditText editText;
public DateFormatTextWatcher(EditText editText) {
this.editText = editText;
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (!s.toString().equals(this.currentText)) {
// Remove all non-digit.
String newTextClean = s.toString().replaceAll("[^\\d.]|\\.", "");
String currentTextClean = this.currentText.replaceAll("[^\\d.]|\\.", "");
int newTextLength = newTextClean.length();
// Cursor Position Index.
int selectionIndex = newTextLength;
for (int i = 2; i <= newTextLength && i < 6; i += 2) {
selectionIndex++;
}
// Fix for pressing delete next to a forward slash
if (newTextClean.equals(currentTextClean)) {
selectionIndex--;
}
if (newTextClean.length() < 8) {
newTextClean = newTextClean + this.DDMMYYYY.substring(newTextClean.length());
} else {
// This part makes sure that when we finish entering numbers
// the date is correct, fixing it otherwise
int day = Integer.parseInt(newTextClean.substring(0,2));
int month = Integer.parseInt(newTextClean.substring(2,4));
int year = Integer.parseInt(newTextClean.substring(4,8));
month = month < 1 ? 1 : month > 12 ? 12 : month;
this.calendar.set(Calendar.MONTH, month-1);
year = (year < 1900)? 1900:(year > 2100)? 2100 : year;
this.calendar.set(Calendar.YEAR, year);
// ^ first set year for the line below to work correctly
// with leap years - otherwise, date e.g. 29/02/2012
// would be automatically corrected to 28/02/2012
day = (day > this.calendar.getActualMaximum(Calendar.DATE))? this.calendar.getActualMaximum(Calendar.DATE):day;
newTextClean = String.format("%02d%02d%02d",day, month, year);
}
// "%s/%s/%s"
String format = "%s" + SEPARATOR + "%s" + SEPARATOR +"%s";
newTextClean = String.format(format, newTextClean.substring(0, 2),
newTextClean.substring(2, 4),
newTextClean.substring(4, 8));
selectionIndex = selectionIndex < 0 ? 0 : selectionIndex;
this.currentText = newTextClean;
this.editText.setText(this.currentText);
this.editText.setSelection(selectionIndex < this.currentText.length() ? selectionIndex : this.currentText.length());
}
}
@Override
public void afterTextChanged(Editable s) {
}
}
Voici l'interface de l'application
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView71"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:text="Birthday:"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/editText_birthDay"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:ems="10"
android:hint="DD/MM/YYYY"
android:inputType="date"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView71" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.java
package org.o7planning.textwatcherdateexample;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextWatcher;
import android.widget.EditText;
public class MainActivity extends AppCompatActivity {
private EditText editText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.editText = (EditText) this.findViewById(R.id.editText_birthDay);
// Create TextWatcher:
TextWatcher textWatcher = new DateFormatTextWatcher(this.editText);
this.editText.addTextChangedListener(textWatcher);
}
}
NumberTextWatcher.java
package org.o7planning.textwatchernumberexample;
import android.text.Editable;
import android.text.TextWatcher;
import android.text.method.DigitsKeyListener;
import android.util.Log;
import android.widget.EditText;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.ParseException;
import java.util.Locale;
public class NumberTextWatcher implements TextWatcher {
private static final String LOG_TAG = "AndroidExample";
private final int numDecimals;
private String groupingSeparator;
private String decimalSeparator;
private boolean nonUsFormat;
private DecimalFormat decimalFormatDec;
private DecimalFormat decimalFormatInt;
private boolean hasFractionalPart;
private EditText editText;
private String value;
public NumberTextWatcher(EditText editText, Locale locale, int numDecimals) {
this.editText = editText;
this.numDecimals = numDecimals;
this.hasFractionalPart = false;
this.editText.setKeyListener(DigitsKeyListener.getInstance("0123456789.,"));
DecimalFormatSymbols symbols = new DecimalFormatSymbols(locale);
char gs = symbols.getGroupingSeparator();
char ds = symbols.getDecimalSeparator();
this.groupingSeparator = String.valueOf(gs);
this.decimalSeparator = String.valueOf(ds);
String patternInt = "#,###";
this.decimalFormatInt = new DecimalFormat(patternInt, symbols);
String patternDec = patternInt + "." + replicate('#', this.numDecimals);
this.decimalFormatDec = new DecimalFormat(patternDec, symbols);
this.decimalFormatDec.setDecimalSeparatorAlwaysShown(true);
this.decimalFormatDec.setRoundingMode(RoundingMode.DOWN);
this.nonUsFormat = !this.decimalSeparator.equals(".");
this.value = null;
}
@Override
public void afterTextChanged(Editable s) {
Log.d(LOG_TAG, "afterTextChanged");
this.editText.removeTextChangedListener(this);
try {
int initLeng = this.editText.getText().length();
String v = this.value.replace(this.groupingSeparator, "");
Number n = this.decimalFormatDec.parse(v);
int selectionStart = this.editText.getSelectionStart();
if (this.hasFractionalPart) {
int decPos = v.indexOf(this.decimalSeparator) + 1;
int decLen = v.length() - decPos;
if (decLen > this.numDecimals) {
v = v.substring(0, decPos + this.numDecimals);
}
int trz = countTrailingZeros(v);
StringBuilder fmt = new StringBuilder(this.decimalFormatDec.format(n));
while (trz-- > 0) {
fmt.append("0");
}
this.editText.setText(fmt.toString());
} else {
this.editText.setText(this.decimalFormatInt.format(n));
}
int endLeng = this.editText.getText().length();
int selection = (selectionStart + (endLeng - initLeng));
if (selection > 0 && selection <= this.editText.getText().length()) {
this.editText.setSelection(selection);
} else {
// Place cursor at the end?
this.editText.setSelection(this.editText.getText().length() - 1);
}
} catch (NumberFormatException | ParseException nfe) {
// Do nothing?
}
this.editText.addTextChangedListener(this);
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
Log.d(LOG_TAG, "beforeTextChanged");
this.value = this.editText.getText().toString();
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
Log.d(LOG_TAG, "onTextChanged");
String newValue = s.toString();
String change = newValue.substring(start, start + count);
String prefix = this.value.substring(0, start);
String suffix = this.value.substring(start + before);
if (".".equals(change) && this.nonUsFormat) {
change = this.decimalSeparator;
}
this.value = prefix + change + suffix;
this.hasFractionalPart = this.value.contains(this.decimalSeparator);
Log.d(LOG_TAG, "VALUE: " + this.value);
}
private int countTrailingZeros(String str) {
int count = 0;
for (int i = str.length() - 1; i >= 0; i--) {
char ch = str.charAt(i);
if ('0' == ch) {
count++;
} else {
break;
}
}
return count;
}
private String replicate(char ch, int n) {
return new String(new char[n]).replace("\0", "" + ch);
}
}
Voici l'interface de l'application
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView71"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginLeft="16dp"
android:layout_marginTop="32dp"
android:layout_marginRight="16dp"
android:text="Enter a Number:"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/editText_number"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:ems="10"
android:inputType="number"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView71" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.java
package org.o7planning.textwatchernumberexample;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextWatcher;
import android.widget.EditText;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
private EditText editTextNumber;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.editTextNumber = (EditText) this.findViewById(R.id.editText_number) ;
Locale locale = new Locale("en", "US");
int numDecs = 2; // Let's use 2 decimals
TextWatcher textWatcher = new NumberTextWatcher(this.editTextNumber, locale, numDecs);
this.editTextNumber.addTextChangedListener(textWatcher);
}
}
