Androidではパスワード入力ボックスの貼り付け・コピーは禁止されています

  /** * Called when a context menu option for the text view is selected.  Currently
 * this will be one of {@link android.R.id#selectAll}, {@link android.R.id#cut},
 * {@link android.R.id#copy}, {@link android.R.id#paste} or {@link android.R.id#shareText}.
 * @return true if the context menu item action was performed.
 */  
 public boolean onTextContextMenuItem(int id){
     …………………………
     switch (id) {
        case ID_SELECT_ALL:
            selectAllText();
            return true;

        case ID_UNDO:
            if (mEditor != null) {
                mEditor.undo();
            }
            return true;  // Returns true even if nothing was undone.

        case ID_REDO:
            if (mEditor != null) {
                mEditor.redo();
            }
            return true;  // Returns true even if nothing was undone.

        case ID_PASTE:
            paste(min, max, true /* withFormatting */);
            return true;

        case ID_PASTE_AS_PLAIN_TEXT:
            paste(min, max, false /* withFormatting */);
            return true;

        case ID_CUT:
            setPrimaryClip(ClipData.newPlainText(null, getTransformedText(min, max)));
            deleteText_internal(min, max);
            return true;

        case ID_COPY:
            setPrimaryClip(ClipData.newPlainText(null, getTransformedText(min, max)));
            stopTextActionMode();
            return true;

        case ID_REPLACE:
            if (mEditor != null) {
                mEditor.replace();
            }
            return true;

        case ID_SHARE:
            shareSelectedText();
            return true;
    }
    return false;
} 

  @Override
public boolean onTextContextMenuItem(int id) {
    if (id == android.R.id.paste) {
        return false;
    }
    return super.onTextContextMenuItem(id);
}  `