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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.AttributeSet;
     21 import android.widget.TextView;
     22 
     23 /**
     24  * Simple TextView which is used to output log data received through the LogNode interface.
     25  */
     26 public class LogView extends TextView implements LogNode {
     27 
     28     public LogView(Context context) {
     29         super(context);
     30     }
     31 
     32     public LogView(Context context, AttributeSet attrs) {
     33         super(context, attrs);
     34     }
     35 
     36     public LogView(Context context, AttributeSet attrs, int defStyle) {
     37         super(context, attrs, defStyle);
     38     }
     39 
     40     /**
     41      * Formats the log data and prints it out to the LogView.
     42      *
     43      * @param priority Log level of the data being logged.  Verbose, Error, etc.
     44      * @param tag      Tag for for the log data.  Can be used to organize log statements.
     45      * @param msg      The actual message to be logged. The actual message to be logged.
     46      * @param tr       If an exception was thrown, this can be sent along for the logging
     47      *                 facilities
     48      *                 to extract and print useful information.
     49      */
     50     @Override
     51     public void println(int priority, String tag, String msg, Throwable tr) {
     52 
     53         String priorityStr = null;
     54 
     55         // For the purposes of this View, we want to print the priority as readable text.
     56         switch (priority) {
     57             case android.util.Log.VERBOSE:
     58                 priorityStr = "VERBOSE";
     59                 break;
     60             case android.util.Log.DEBUG:
     61                 priorityStr = "DEBUG";
     62                 break;
     63             case android.util.Log.INFO:
     64                 priorityStr = "INFO";
     65                 break;
     66             case android.util.Log.WARN:
     67                 priorityStr = "WARN";
     68                 break;
     69             case android.util.Log.ERROR:
     70                 priorityStr = "ERROR";
     71                 break;
     72             case android.util.Log.ASSERT:
     73                 priorityStr = "ASSERT";
     74                 break;
     75             default:
     76                 break;
     77         }
     78 
     79         // Handily, the Log class has a facility for converting a stack trace into a usable string.
     80         String exceptionStr = null;
     81         if (tr != null) {
     82             exceptionStr = android.util.Log.getStackTraceString(tr);
     83         }
     84 
     85         // Take the priority, tag, message, and exception, and concatenate as necessary
     86         // into one usable line of text.
     87         final StringBuilder outputBuilder = new StringBuilder();
     88 
     89         String delimiter = "\t";
     90         appendIfNotNull(outputBuilder, priorityStr, delimiter);
     91         appendIfNotNull(outputBuilder, tag, delimiter);
     92         appendIfNotNull(outputBuilder, msg, delimiter);
     93         appendIfNotNull(outputBuilder, exceptionStr, delimiter);
     94 
     95         // In case this was originally called from an AsyncTask or some other off-UI thread,
     96         // make sure the update occurs within the UI thread.
     97         ((Activity) getContext()).runOnUiThread((new Thread(new Runnable() {
     98             @Override
     99             public void run() {
    100                 // Display the text we just generated within the LogView.
    101                 appendToLog(outputBuilder.toString());
    102             }
    103         })));
    104 
    105         if (mNext != null) {
    106             mNext.println(priority, tag, msg, tr);
    107         }
    108     }
    109 
    110     public LogNode getNext() {
    111         return mNext;
    112     }
    113 
    114     public void setNext(LogNode node) {
    115         mNext = node;
    116     }
    117 
    118     /**
    119      * Takes a string and adds to it, with a separator, if the bit to be added isn't null. Since
    120      * the logger takes so many arguments that might be null, this method helps cut out some of the
    121      * agonizing tedium of writing the same 3 lines over and over.
    122      *
    123      * @param source    StringBuilder containing the text to append to.
    124      * @param addStr    The String to append
    125      * @param delimiter The String to separate the source and appended strings. A tab or comma,
    126      *                  for instance.
    127      * @return The fully concatenated String as a StringBuilder
    128      */
    129     private StringBuilder appendIfNotNull(StringBuilder source, String addStr, String delimiter) {
    130         if (addStr != null) {
    131             if (addStr.length() == 0) {
    132                 delimiter = "";
    133             }
    134 
    135             return source.append(addStr).append(delimiter);
    136         }
    137         return source;
    138     }
    139 
    140     // The next LogNode in the chain.
    141     LogNode mNext;
    142 
    143     /** Outputs the string as a new line of log data in the LogView. */
    144     public void appendToLog(String s) {
    145         append("\n" + s);
    146     }
    147 
    148 
    149 }
    150