LogView.java

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
}