分析：新建短信，当我们接受人RecipientsEditor中输入+86的时候，系统会自动在+86后加入空格

我们可以认为这是一个很人性的格式化操作，在ComposeMessageActivity中系统在调用initRecipientsEditor（）方法对联系人进行初始化的时候调用了 PhoneNumberFormatter.setPhoneNumberFormattingTextWatcher(this, mRecipientsEditor);我们通过对代码进行追踪发现，最终调用了Framework中PhoneNumberFormattingTextWatcher类对电话号码进行格式化处理，并在处理后在PhoneNumberFormatter中使用异步类控件的值进行处理，这里贴处该类的代码进行分析。

package android.telephony;

import com.android.i18n.phonenumbers.AsYouTypeFormatter;

import com.android.i18n.phonenumbers.PhoneNumberUtil;

import android.telephony.PhoneNumberUtils;

import android.text.Editable;

import android.text.Selection;

import android.text.TextWatcher;

import java.util.Locale;

/**

* Watches a {@link android.widget.TextView} and if a phone number is entered

* will format it.

* <p>

* Stop formatting when the user

* <ul>

* <li>Inputs non-dialable characters</li>

* <li>Removes the separator in the middle of string.</li>

* </ul>

* <p>

* The formatting will be restarted once the text is cleared.

*/

public class PhoneNumberFormattingTextWatcher implements TextWatcher {

/**

* Indicates the change was caused by ourselves.

*/

private boolean mSelfChange = false;

/**

* Indicates the formatting has been stopped.

*/

private boolean mStopFormatting;

private AsYouTypeFormatter mFormatter;

/**

* The formatting is based on the current system locale and future locale changes

* may not take effect on this instance.

*/

public PhoneNumberFormattingTextWatcher() {

this(Locale.getDefault().getCountry());

}

/**

* The formatting is based on the given <code>countryCode</code>.

*

* @param countryCode the ISO 3166-1 two-letter country code that indicates the country/region

* where the phone number is being entered.

*

* @hide

*/

public PhoneNumberFormattingTextWatcher(String countryCode) {

if (countryCode == null) throw new IllegalArgumentException();

mFormatter = PhoneNumberUtil.getInstance().getAsYouTypeFormatter(countryCode);

}

@Override

public void beforeTextChanged(CharSequence s, int start, int count,

int after) {

if (mSelfChange || mStopFormatting) {

return;

}

// If the user manually deleted any non-dialable characters, stop formatting

if (count > 0 && hasSeparator(s, start, count)) {

stopFormatting();

}

}

@Override

public void onTextChanged(CharSequence s, int start, int before, int count) {

if (mSelfChange || mStopFormatting) {

return;

}

// If the user inserted any non-dialable characters, stop formatting

if (count > 0 && hasSeparator(s, start, count)) {

stopFormatting();

}

}

@Override

public synchronized void afterTextChanged(Editable s) {

if (mStopFormatting) {

// Restart the formatting when all texts were clear.

mStopFormatting = !(s.length() == 0);

return;

}

if (mSelfChange) {

// Ignore the change caused by s.replace().

return;

}

String formatted = reformat(s, Selection.getSelectionEnd(s));

if (formatted != null) {

int rememberedPos = mFormatter.getRememberedPosition();

mSelfChange = true;

s.replace(0, s.length(), formatted, 0, formatted.length());

// The text could be changed by other TextWatcher after we changed it. If we found the

// text is not the one we were expecting, just give up calling setSelection().

if (formatted.equals(s.toString())) {

Selection.setSelection(s, rememberedPos);

}

mSelfChange = false;

}

}

/**

* Generate the formatted number by ignoring all non-dialable chars and stick the cursor to the

* nearest dialable char to the left. For instance, if the number is (650) 123-45678 and '4' is

* removed then the cursor should be behind '3' instead of '-'.

*/

private String reformat(CharSequence s, int cursor) {

// The index of char to the leftward of the cursor.

int curIndex = cursor - 1;

String formatted = null;

mFormatter.clear();

char lastNonSeparator = 0;

boolean hasCursor = false;

int len = s.length();

for (int i = 0; i < len; i++) {

char c = s.charAt(i);

if (PhoneNumberUtils.isNonSeparator(c)) {

if (lastNonSeparator != 0) {

formatted = getFormattedNumber(lastNonSeparator, hasCursor);

hasCursor = false;

}

lastNonSeparator = c;

}

if (i == curIndex) {

hasCursor = true;

}

}

if (lastNonSeparator != 0) {

formatted = getFormattedNumber(lastNonSeparator, hasCursor);

}

return formatted;

}

private String getFormattedNumber(char lastNonSeparator, boolean hasCursor) {

return hasCursor ? mFormatter.inputDigitAndRememberPosition(lastNonSeparator)

: mFormatter.inputDigit(lastNonSeparator);

}

private void stopFormatting() {

mStopFormatting = true;

mFormatter.clear();

}

private boolean hasSeparator(final CharSequence s, final int start, final int count) {

for (int i = start; i < start + count; i++) {

char c = s.charAt(i);

if (!PhoneNumberUtils.isNonSeparator(c)) {

return true;

}

}

return false;

}

}

通过查看PhoneNumberFormattingTextWatcher代码我们发现，该类继承至TextWatcher，则实现了对RecipientEditor的值的变化进行了监听，最后调用PhoneNumberUtils进行处理。