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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.widget;
     18 
     19 import android.os.Handler;
     20 
     21 /**
     22  * Provides callbacks indicating the steps in two digit pressing within a
     23  * timeout.
     24  *
     25  * Package private: only relevant in helping {@link TimeSpinnerHelper}.
     26  */
     27 class DoubleDigitManager {
     28 
     29     private final long timeoutInMillis;
     30     private final CallBack mCallBack;
     31 
     32     private Integer intermediateDigit;
     33 
     34     /**
     35      * @param timeoutInMillis How long after the first digit is pressed does
     36      *   the user have to press the second digit?
     37      * @param callBack The callback to indicate what's going on with the user.
     38      */
     39     public DoubleDigitManager(long timeoutInMillis, CallBack callBack) {
     40         this.timeoutInMillis = timeoutInMillis;
     41         mCallBack = callBack;
     42     }
     43 
     44     /**
     45      * Report to this manager that a digit was pressed.
     46      * @param digit
     47      */
     48     public void reportDigit(int digit) {
     49         if (intermediateDigit == null) {
     50             intermediateDigit = digit;
     51 
     52             new Handler().postDelayed(new Runnable() {
     53                 public void run() {
     54                     if (intermediateDigit != null) {
     55                         mCallBack.singleDigitFinal(intermediateDigit);
     56                         intermediateDigit = null;
     57                     }
     58                 }
     59             }, timeoutInMillis);
     60 
     61             if (!mCallBack.singleDigitIntermediate(digit)) {
     62 
     63                 // this wasn't a good candidate for the intermediate digit,
     64                 // make it the final digit (since there is no opportunity to
     65                 // reject the final digit).
     66                 intermediateDigit = null;
     67                 mCallBack.singleDigitFinal(digit);
     68             }
     69         } else if (mCallBack.twoDigitsFinal(intermediateDigit, digit)) {
     70              intermediateDigit = null;
     71         }
     72     }
     73 
     74     /**
     75      * The callback to indicate what is going on with the digits pressed.
     76      */
     77     static interface CallBack {
     78 
     79         /**
     80          * A digit was pressed, and there are no intermediate digits.
     81          * @param digit The digit pressed.
     82          * @return Whether the digit was accepted; how the user of this manager
     83          *   tells us that the intermediate digit is acceptable as an
     84          *   intermediate digit.
     85          */
     86         boolean singleDigitIntermediate(int digit);
     87 
     88         /**
     89          * A single digit was pressed, and it is 'the final answer'.
     90          * - a single digit pressed, and the timeout expires.
     91          * - a single digit pressed, and {@link #singleDigitIntermediate}
     92          *   returned false.
     93          * @param digit The digit.
     94          */
     95         void singleDigitFinal(int digit);
     96 
     97         /**
     98          * The user pressed digit1, then digit2 within the timeout.
     99          * @param digit1
    100          * @param digit2
    101          */
    102         boolean twoDigitsFinal(int digit1, int digit2);
    103     }
    104 
    105 }
    106