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 */
16package com.example.android.common.logger;
17
18import android.app.Activity;
19import android.content.Context;
20import android.util.*;
21import android.widget.TextView;
22
23/** Simple TextView which is used to output log data received through the LogNode interface.
24*/
25public 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