Home | History | Annotate | Download | only in content 
      1 /*
      2  * Copyright (C) 2013 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 com.example.android.apis.content;
     18 
     19 import com.example.android.apis.R;
     20 
     21 import android.app.Activity;
     22 import android.os.Bundle;
     23 import android.text.Editable;
     24 import android.text.InputFilter;
     25 import android.text.Spanned;
     26 import android.text.TextWatcher;
     27 import android.text.method.DigitsKeyListener;
     28 import android.util.Log;
     29 import android.view.View;
     30 import android.widget.Button;
     31 import android.widget.EditText;
     32 
     33 /**
     34  * Simple example of using an UndoManager for editing text in a TextView.
     35  */
     36 public class TextUndoActivity extends Activity {
     37     // Characters allowed as input in the credit card field.
     38     private static final String CREDIT_CARD_CHARS = "0123456789 ";
     39 
     40     EditText mDefaultText;
     41     EditText mLengthLimitText;
     42     EditText mCreditCardText;
     43 
     44     @Override
     45     protected void onCreate(Bundle savedInstanceState) {
     46         super.onCreate(savedInstanceState);
     47 
     48         setContentView(R.layout.text_undo);
     49 
     50         mDefaultText = (EditText) findViewById(R.id.default_text);
     51         ((Button) findViewById(R.id.set_text)).setOnClickListener(new View.OnClickListener() {
     52             @Override
     53             public void onClick(View v) {
     54                 mDefaultText.setText("some text");
     55             }
     56         });
     57         ((Button) findViewById(R.id.append_text)).setOnClickListener(new View.OnClickListener() {
     58             @Override
     59             public void onClick(View v) {
     60                 mDefaultText.append(" append");
     61             }
     62         });
     63         ((Button) findViewById(R.id.insert_text)).setOnClickListener(new View.OnClickListener() {
     64             @Override
     65             public void onClick(View v) {
     66                 Editable editable = mDefaultText.getText();
     67                 editable.insert(0, "insert ");
     68             }
     69         });
     70 
     71         mLengthLimitText = (EditText) findViewById(R.id.length_limit_text);
     72         mLengthLimitText.setFilters(new InputFilter[] { new InputFilter.LengthFilter(4) });
     73 
     74         mCreditCardText = (EditText) findViewById(R.id.credit_card_text);
     75         mCreditCardText.setKeyListener(DigitsKeyListener.getInstance(CREDIT_CARD_CHARS));
     76         mCreditCardText.addTextChangedListener(new CreditCardTextWatcher());
     77      }
     78 
     79     /**
     80      * A simple credit card input formatter that adds spaces every 4 characters.
     81      */
     82     private static class CreditCardTextWatcher implements TextWatcher {
     83         @Override
     84         public void beforeTextChanged(CharSequence s, int start, int count, int after) {
     85         }
     86 
     87         @Override
     88         public void onTextChanged(CharSequence s, int start, int before, int count) {
     89         }
     90 
     91         @Override
     92         public void afterTextChanged(Editable s) {
     93             String original = s.toString();
     94             String formatted = addSpaces(getNumbers(original));
     95             // This is an ugly way to avoid infinite recursion, but it's common in app code.
     96             if (!formatted.equals(original)) {
     97                 s.replace(0, s.length(), formatted);
     98             }
     99         }
    100 
    101         /**
    102          * @return Returns a string with a space added every 4 characters.
    103          */
    104         private static String addSpaces(CharSequence str) {
    105             StringBuilder builder = new StringBuilder();
    106             int len = str.length();
    107             for (int i = 0; i < len; i += 4) {
    108                 if (i + 4 < len) {
    109                     builder.append(str.subSequence(i, i + 4));
    110                     builder.append(' ');
    111                 } else {
    112                     // Don't put a space after the end.
    113                     builder.append(str.subSequence(i, len));
    114                 }
    115             }
    116             return builder.toString();
    117         }
    118 
    119         /**
    120          * @return Returns a string containing only the digits from a character sequence.
    121          */
    122         private static String getNumbers(CharSequence cc) {
    123             StringBuilder sb = new StringBuilder(16);
    124             for (int i = 0, count = cc.length(); i < count; ++i) {
    125                 char c = cc.charAt(i);
    126                 if (isNumber(c)) {
    127                     sb.append(c);
    128                 }
    129             }
    130             return sb.toString();
    131         }
    132 
    133         private static boolean isNumber(char c) {
    134             return c >= '0' && c <= '9';
    135         }
    136 
    137     }
    138 }
    139