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      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 package com.example.android.common.logger;
     17 
     18 import android.app.Activity;
     19 import android.content.Context;
     20 import android.util.*;
     21 import android.widget.TextView;
     22 
     23 /** Simple TextView which is used to output log data received through the LogNode interface.
     24 */
     25 public class LogView extends TextView implements LogNode {
     26 
     27     public LogView(Context context) {
     28         super(context);
     29     }
     30 
     31     public LogView(Context context, AttributeSet attrs) {
     32         super(context, attrs);
     33     }
     34 
     35     public LogView(Context context, AttributeSet attrs, int defStyle) {
     36         super(context, attrs, defStyle);
     37     }
     38 
     39     /**
     40      * Formats the log data and prints it out to the LogView.
     41      * @param priority Log level of the data being logged.  Verbose, Error, etc.
     42      * @param tag Tag for for the log data.  Can be used to organize log statements.
     43      * @param msg The actual message to be logged. The actual message to be logged.
     44      * @param tr If an exception was thrown, this can be sent along for the logging facilities
     45      *           to extract and print useful information.
     46      */
     47     @Override
     48     public void println(int priority, String tag, String msg, Throwable tr) {
     49 
     50 
     51         String priorityStr = null;
     52 
     53         // For the purposes of this View, we want to print the priority as readable text.
     54         switch(priority) {
     55             case android.util.Log.VERBOSE:
     56                 priorityStr = "VERBOSE";
     57                 break;
     58             case android.util.Log.DEBUG:
     59                 priorityStr = "DEBUG";
     60                 break;
     61             case android.util.Log.INFO:
     62                 priorityStr = "INFO";
     63                 break;
     64             case android.util.Log.WARN:
     65                 priorityStr = "WARN";
     66                 break;
     67             case android.util.Log.ERROR:
     68                 priorityStr = "ERROR";
     69                 break;
     70             case android.util.Log.ASSERT:
     71                 priorityStr = "ASSERT";
     72                 break;
     73             default:
     74                 break;
     75         }
     76 
     77         // Handily, the Log class has a facility for converting a stack trace into a usable string.
     78         String exceptionStr = null;
     79         if (tr != null) {
     80             exceptionStr = android.util.Log.getStackTraceString(tr);
     81         }
     82 
     83         // Take the priority, tag, message, and exception, and concatenate as necessary
     84         // into one usable line of text.
     85         final StringBuilder outputBuilder = new StringBuilder();
     86 
     87         String delimiter = "\t";
     88         appendIfNotNull(outputBuilder, priorityStr, delimiter);
     89         appendIfNotNull(outputBuilder, tag, delimiter);
     90         appendIfNotNull(outputBuilder, msg, delimiter);
     91         appendIfNotNull(outputBuilder, exceptionStr, delimiter);
     92 
     93         // In case this was originally called from an AsyncTask or some other off-UI thread,
     94         // make sure the update occurs within the UI thread.
     95         ((Activity) getContext()).runOnUiThread( (new Thread(new Runnable() {
     96             @Override
     97             public void run() {
     98                 // Display the text we just generated within the LogView.
     99                 appendToLog(outputBuilder.toString());
    100             }
    101         })));
    102 
    103         if (mNext != null) {
    104             mNext.println(priority, tag, msg, tr);
    105         }
    106     }
    107 
    108     public LogNode getNext() {
    109         return mNext;
    110     }
    111 
    112     public void setNext(LogNode node) {
    113         mNext = node;
    114     }
    115 
    116     /** Takes a string and adds to it, with a separator, if the bit to be added isn't null. Since
    117      * the logger takes so many arguments that might be null, this method helps cut out some of the
    118      * agonizing tedium of writing the same 3 lines over and over.
    119      * @param source StringBuilder containing the text to append to.
    120      * @param addStr The String to append
    121      * @param delimiter The String to separate the source and appended strings. A tab or comma,
    122      *                  for instance.
    123      * @return The fully concatenated String as a StringBuilder
    124      */
    125     private StringBuilder appendIfNotNull(StringBuilder source, String addStr, String delimiter) {
    126         if (addStr != null) {
    127             if (addStr.length() == 0) {
    128                 delimiter = "";
    129             }
    130 
    131             return source.append(addStr).append(delimiter);
    132         }
    133         return source;
    134     }
    135 
    136     // The next LogNode in the chain.
    137     LogNode mNext;
    138 
    139     /** Outputs the string as a new line of log data in the LogView. */
    140     public void appendToLog(String s) {
    141         append("\n" + s);
    142     }
    143 
    144 
    145 }
    146