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BasicMultitouch / src / com.example.android.common.logger /

LogView.java

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/*
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 * Copyright (C) 2013 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package com.example.android.common.logger;
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import android.app.Activity;
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import android.content.Context;
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import android.util.*;
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import android.widget.TextView;
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/** Simple TextView which is used to output log data received through the LogNode interface.
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*/
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public class LogView extends TextView implements LogNode {
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    public LogView(Context context) {
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        super(context);
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    }
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    public LogView(Context context, AttributeSet attrs) {
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        super(context, attrs);
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    }
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    public LogView(Context context, AttributeSet attrs, int defStyle) {
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        super(context, attrs, defStyle);
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    }
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    /**
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     * Formats the log data and prints it out to the LogView.
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     * @param priority Log level of the data being logged.  Verbose, Error, etc.
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     * @param tag Tag for for the log data.  Can be used to organize log statements.
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     * @param msg The actual message to be logged. The actual message to be logged.
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     * @param tr If an exception was thrown, this can be sent along for the logging facilities
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     *           to extract and print useful information.
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     */
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    @Override
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    public void println(int priority, String tag, String msg, Throwable tr) {
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        String priorityStr = null;
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        // For the purposes of this View, we want to print the priority as readable text.
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        switch(priority) {
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            case android.util.Log.VERBOSE:
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                priorityStr = "VERBOSE";
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                break;
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            case android.util.Log.DEBUG:
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                priorityStr = "DEBUG";
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                break;
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            case android.util.Log.INFO:
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                priorityStr = "INFO";
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                break;
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            case android.util.Log.WARN:
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                priorityStr = "WARN";
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                break;
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            case android.util.Log.ERROR:
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                priorityStr = "ERROR";
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                break;
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            case android.util.Log.ASSERT:
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                priorityStr = "ASSERT";
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                break;
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            default:
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                break;
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        }
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        // Handily, the Log class has a facility for converting a stack trace into a usable string.
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        String exceptionStr = null;
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        if (tr != null) {
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            exceptionStr = android.util.Log.getStackTraceString(tr);
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        }
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        // Take the priority, tag, message, and exception, and concatenate as necessary
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        // into one usable line of text.
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        final StringBuilder outputBuilder = new StringBuilder();
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        String delimiter = "\t";
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        appendIfNotNull(outputBuilder, priorityStr, delimiter);
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        appendIfNotNull(outputBuilder, tag, delimiter);
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        appendIfNotNull(outputBuilder, msg, delimiter);
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        appendIfNotNull(outputBuilder, exceptionStr, delimiter);
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        // In case this was originally called from an AsyncTask or some other off-UI thread,
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        // make sure the update occurs within the UI thread.
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        ((Activity) getContext()).runOnUiThread( (new Thread(new Runnable() {
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            @Override
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            public void run() {
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                // Display the text we just generated within the LogView.
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                appendToLog(outputBuilder.toString());
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            }
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        })));
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        if (mNext != null) {
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            mNext.println(priority, tag, msg, tr);
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        }
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    }
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    public LogNode getNext() {
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        return mNext;
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    }
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    public void setNext(LogNode node) {
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        mNext = node;
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    }
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    /** Takes a string and adds to it, with a separator, if the bit to be added isn't null. Since
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     * the logger takes so many arguments that might be null, this method helps cut out some of the
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     * agonizing tedium of writing the same 3 lines over and over.
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     * @param source StringBuilder containing the text to append to.
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     * @param addStr The String to append
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     * @param delimiter The String to separate the source and appended strings. A tab or comma,
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     *                  for instance.
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     * @return The fully concatenated String as a StringBuilder
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     */
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    private StringBuilder appendIfNotNull(StringBuilder source, String addStr, String delimiter) {
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        if (addStr != null) {
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            if (addStr.length() == 0) {
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                delimiter = "";
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            }
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            return source.append(addStr).append(delimiter);
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        }
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        return source;
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    }
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    // The next LogNode in the chain.
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    LogNode mNext;
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    /** Outputs the string as a new line of log data in the LogView. */
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    public void appendToLog(String s) {
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        append("\n" + s);
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    }
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}