android源碼追蹤學習 RecipientsEditor

RecipientsEditor 建立簡訊時輸入收接者的editor，

public class RecipientsEditor extends MultiAutoCompleteTextView {    private int mLongPressedPosition = -1;    private final RecipientsEditorTokenizer mTokenizer;    private char mLastSeparator = ',';    public RecipientsEditor(Context context, AttributeSet attrs) {        super(context, attrs, android.R.attr.autoCompleteTextViewStyle);        mTokenizer = new RecipientsEditorTokenizer(context, this);        setTokenizer(mTokenizer);        // For the focus to move to the message body when soft Next is pressed        setImeOptions(EditorInfo.IME_ACTION_NEXT);        // Set threshold as 1 CharSequence.        setThreshold(1);        addTextChangedListener(new TextWatcher() {            private Annotation[] mAffected;            public void beforeTextChanged(CharSequence s, int start,                    int count, int after) {                mAffected = ((Spanned) s).getSpans(start, start + count,                        Annotation.class);            }            public void onTextChanged(CharSequence s, int start,                    int before, int after) {                if (before == 0 && after == 1) {    // inserting a character                    char c = s.charAt(start);                    if (c == ',' || c == ';') {                        // Remember the delimiter the user typed to end this recipient. We'll                        // need it shortly in terminateToken().                        mLastSeparator = c;                    }                }            }            public void afterTextChanged(Editable s) {                if (mAffected != null) {                    for (Annotation a : mAffected) {                        s.removeSpan(a);                    }                }                mAffected = null;            }        });    }

RecipientsEditor 繼承於 MultiAutoCompleteTextView

可支援輸入多個手機號碼，每個手機號碼用用分隔字元分開，有自動完成功能，預置匹配的資料為連絡人；

其中RecipientsEditorTokenizer為了找出輸入字串中的分隔字元","和“，”

private class RecipientsEditorTokenizer            implements MultiAutoCompleteTextView.Tokenizer {        private final MultiAutoCompleteTextView mList;        private final Context mContext;        RecipientsEditorTokenizer(Context context, MultiAutoCompleteTextView list) {            mList = list;            mContext = context;        }        public int findTokenStart(CharSequence text, int cursor) {            int i = cursor;            char c;            while (i > 0 && (c = text.charAt(i - 1)) != ',' && c != ';') {                i--;            }            while (i < cursor && text.charAt(i) == ' ') {                i++;            }            return i;        }        public int findTokenEnd(CharSequence text, int cursor) {            int i = cursor;            int len = text.length();            char c;            while (i < len) {                if ((c = text.charAt(i)) == ',' || c == ';') {                    return i;                } else {                    i++;                }            }            return len;        }        public CharSequence terminateToken(CharSequence text) {            int i = text.length();            while (i > 0 && text.charAt(i - 1) == ' ') {                i--;            }            char c;            if (i > 0 && ((c = text.charAt(i - 1)) == ',' || c == ';')) {                return text;            } else {                // Use the same delimiter the user just typed.                // This lets them have a mixture of commas and semicolons in their list.                String separator = mLastSeparator + " ";                if (text instanceof Spanned) {                    SpannableString sp = new SpannableString(text + separator);                    TextUtils.copySpansFrom((Spanned) text, 0, text.length(),                                            Object.class, sp, 0);                    return sp;                } else {                    return text + separator;                }            }        }

setImeOptions(EditorInfo.IME_ACTION_NEXT);//設定軟鍵盤右下角的button的功能為下一個，即切換到下一個輸入框，如果設定成EditorInfo.IME_ACTION_DONE，則表示輸入完成，關掉軟鍵盤，還有很多其他的選項可供設定的

setThreshold(1);// Threshold門檻的意思，此處設定只要輸入一個字元就開始匹配，若設定為“2”則表示要輸入兩個字元才是匹配。

addTextChangedListener(TextWatcher);//添加一個TextView監聽器

TextWatcher裡有三個回調方法，當有輸入框裡的字元有變化時會自動依次調用以下三個方法：

beforeTextChanged(CharSequence s, int start,int count, int after) ；

//此處已輸入為例解釋上面各變數的意思，s 是輸入以前的字串，start游標所在的位置， count為要改變的字元個數，即選中的個數，after為要插入的個數

onTextChanged(CharSequence s, int start, int before, int after)

//s為改變後的字串，start和上面的start一樣， before和上面的count一樣，after與上面的after一樣

afterTextChanged(Editable s)// s為改變後的字串

預製匹配資料為連絡人的方法是通過設定適配器：

 mRecipientsEditor.setAdapter(new RecipientsAdapter(this));

RecipientsAdapter 是extends ResourceCursorAdapter的

在適配器裡面通過Phone.CONTENT_FILTER_URI，擷取電話本裡的資訊。