それはあなたが実際にそれを行う方法ですInputFilter：
final String prefix = "http://"
editText.setText(prefix);
editText.setFilters(new InputFilter[] {
new InputFilter() {
@Override
public CharSequence filter(final CharSequence source, final int start,
final int end, final Spanned dest, final int dstart, final int dend) {
final int newStart = Math.max(prefix.length(), dstart);
final int newEnd = Math.max(prefix.length(), dend);
if (newStart != dstart || newEnd != dend) {
final SpannableStringBuilder builder = new SpannableStringBuilder(dest);
builder.replace(newStart, newEnd, source);
if (source instanceof Spanned) {
TextUtils.copySpansFrom(
(Spanned) source, 0, source.length(), null, builder, newStart);
}
Selection.setSelection(builder, newStart + source.length());
return builder;
} else {
return null;
}
}
}
});
プレフィックスも選択できないようにする場合は、次のコードを追加できます。
final SpanWatcher watcher = new SpanWatcher() {
@Override
public void onSpanAdded(final Spannable text, final Object what,
final int start, final int end) {
// Nothing here.
}
@Override
public void onSpanRemoved(final Spannable text, final Object what,
final int start, final int end) {
// Nothing here.
}
@Override
public void onSpanChanged(final Spannable text, final Object what,
final int ostart, final int oend, final int nstart, final int nend) {
if (what == Selection.SELECTION_START) {
if (nstart < prefix.length()) {
final int end = Math.max(prefix.length(), Selection.getSelectionEnd(text));
Selection.setSelection(text, prefix.length(), end);
}
} else if (what == Selection.SELECTION_END) {
final int start = Math.max(prefix.length(), Selection.getSelectionEnd(text));
final int end = Math.max(start, nstart);
if (end != nstart) {
Selection.setSelection(text, start, end);
}
}
}
};
editText.getText().setSpan(watcher, 0, 0, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);