Android Log工具类

文章目录

1. 1. 概要
2. 2. 减少一个 Log 参数
3. 3. 跳转到源代码 Log 调用处
4. 4. 屏蔽所有 Log
5. 5. 使用方法

工欲善其事，必先利其器。在 Android 开发过程中，相信都会遇到这样的问题：

• Log 太多，不容易找到自己设置打印的内容
• 找到 Log 但是定位到 Java 源码有不是很方便
• 对 Log 打印需要设置 Tag，大多时候 Tag 就是本类的类名，存在重复的工作
• 发布正式版本需要注释或者关掉很多 Log 开关

概要

参考 Android 源码，使用官方的 Log 打印方法（设置Tag），然后再 Eclipse 里面设置过滤标签，这样就可以查看某一个类的 Log 了，但是这样效率比较低下。基于上面的一些问题，我研究实现了一种简单易用的 Log 工具类。我的工具类主要有如下特点：

• 减少一个 Log 参数
• 调用某些 Log 方法，可以实现跳转到 Java 源代码的功能
• 采用此工具类，屏蔽 Log 只需要关闭 Log 总开关即可

减少一个 Log 参数

实现方法是采用 StackTraceElement 获取调用类的方法，代码如下：

private static String getClassName() {
    String result = "";
    StackTraceElement thisMethodStack = (new Exception()).getStackTrace()[2];
    result = thisMethodStack.getClassName();
    return result;
}

跳转到源代码 Log 调用处

实现双击 Log 跳转到 Java 源代码调用处，实现方法是参考 Android Logcat 错处日志，发现 Eclipse 实现跳转是因为 Log 中有 at MyClassName.MyMethodName(MClassName.java:行数) 。具体见代码：

/**
 * Realization of double click jump events.
 * 
 * @return
 */
private static String callMethodAndLine() {
    String result = "at ";
    StackTraceElement thisMethodStack = (new Exception()).getStackTrace()[2];
    result += thisMethodStack.getClassName() + ".";
    result += thisMethodStack.getMethodName();
    result += "(" + thisMethodStack.getFileName();
    result += ":" + thisMethodStack.getLineNumber() + ")  ";
    return result;
}

屏蔽所有 Log

采用 LogUtils 工具类，只需要将此类中DEBUG_LEVEL设置的值大一点。

• 如果想要屏蔽所有的 Log 只需要将 DEBUG_LEVEL 设置为 Log.ASSERT 即可。
• 如果想要只显示 Error 则只需要将 DEBUG_LEVEL 设置为 Log.WARN 即可。
• 如果只想要显示 Error 和 Warn 则将 DEBUG_LEVEL 设置为 Log.INFO 即可。

使用方法

只需要用 LogUtils 替换掉 Android 系统的 Log 类，并去掉 log 方法的第一个参数，例如：

LogUtils.d(Object); // 次行代码将打印Object类的toString()

无代码无真相，下面是此工具类源码：

/**
 * Copyright 2014 Zhenguo Jin
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.worthed.util;

import android.util.Log;

/**
 * This class can replace android.util.Log.
 * 
 * @author jingle1267@163.com
 * 
 * @description And you can turn off the log by set DEBUG_LEVEL = Log.ASSERT.
 * 
 */
public class LogUtils {

    /**
     * Master switch.To catch error info you need set this value below Log.WARN
     */
    public static final int DEBUG_LEVEL = 0;

    /**
     * 'System.out' switch.When it is true, you can see the 'System.out' log.
     * Otherwise, you cannot.
     */
    public static final boolean DEBUG_SYSOUT = false;

    /**
     * Send a {@link #VERBOSE} log message.
     * 
     * @param obj
     */
    public static void v(Object obj) {
        if (Log.VERBOSE > DEBUG_LEVEL) {
            String tag = getClassName();
            String msg = obj != null ? obj.toString() : "obj == null";
            Log.v(tag, msg);
        }
    }

    /**
     * Send a {@link #DEBUG_LEVEL} log message.
     * 
     * @param obj
     */
    public static void d(Object obj) {
        if (Log.DEBUG > DEBUG_LEVEL) {
            String tag = getClassName();
            String msg = obj != null ? obj.toString() : "obj == null";
            Log.d(tag, msg);
        }
    }

    /**
     * Send an {@link #INFO} log message.
     * 
     * @param obj
     */
    public static void i(Object obj) {
        if (Log.INFO > DEBUG_LEVEL) {
            String tag = getClassName();
            String msg = obj != null ? obj.toString() : "obj == null";
            Log.i(tag, msg);
        }
    }

    /**
     * Send a {@link #WARN} log message.
     * 
     * @param obj
     */
    public static void w(Object obj) {
        if (Log.WARN > DEBUG_LEVEL) {
            String tag = getClassName();
            String msg = obj != null ? obj.toString() : "obj == null";
            Log.w(tag, msg);
        }
    }

    /**
     * Send an {@link #ERROR} log message.
     * 
     * @param obj
     */
    public static void e(Object obj) {
        if (Log.ERROR > DEBUG_LEVEL) {
            String tag = getClassName();
            String msg = obj != null ? obj.toString() : "obj == null";
            Log.e(tag, msg);
        }
    }

    /**
     * What a Terrible Failure: Report a condition that should never happen. The
     * error will always be logged at level ASSERT with the call stack.
     * Depending on system configuration, a report may be added to the
     * {@link android.os.DropBoxManager} and/or the process may be terminated
     * immediately with an error dialog.
     * 
     * @param obj
     */
    public static void wtf(Object obj) {
        if (Log.ASSERT > DEBUG_LEVEL) {
            String tag = getClassName();
            String msg = obj != null ? obj.toString() : "obj == null";
            Log.wtf(tag, msg);
        }
    }

    /**
     * Send a {@link #VERBOSE} log message.
     * 
     * @param tag
     *            Used to identify the source of a log message. It usually
     *            identifies the class or activity where the log call occurs.
     * @param msg
     *            The message you would like logged.
     */
    public static void v(String tag, String msg) {
        if (Log.VERBOSE > DEBUG_LEVEL) {
            Log.v(tag, msg);
        }
    }

    /**
     * Send a {@link #DEBUG_LEVEL} log message.
     * 
     * @param tag
     *            Used to identify the source of a log message. It usually
     *            identifies the class or activity where the log call occurs.
     * @param msg
     *            The message you would like logged.
     */
    public static void d(String tag, String msg) {
        if (Log.DEBUG > DEBUG_LEVEL) {
            Log.d(tag, msg);
        }
    }

    /**
     * Send an {@link #INFO} log message.
     * 
     * @param tag
     *            Used to identify the source of a log message. It usually
     *            identifies the class or activity where the log call occurs.
     * @param msg
     *            The message you would like logged.
     */
    public static void i(String tag, String msg) {
        if (Log.INFO > DEBUG_LEVEL) {
            Log.i(tag, msg);
        }
    }

    /**
     * Send a {@link #WARN} log message.
     * 
     * @param tag
     *            Used to identify the source of a log message. It usually
     *            identifies the class or activity where the log call occurs.
     * @param msg
     *            The message you would like logged.
     */
    public static void w(String tag, String msg) {
        if (Log.WARN > DEBUG_LEVEL) {
            Log.w(tag, msg);
        }
    }

    /**
     * Send an {@link #ERROR} log message.
     * 
     * @param tag
     *            Used to identify the source of a log message. It usually
     *            identifies the class or activity where the log call occurs.
     * @param msg
     *            The message you would like logged.
     */
    public static void e(String tag, String msg) {
        if (Log.ERROR > DEBUG_LEVEL) {
            Log.e(tag, msg);
        }
    }

    /**
     * What a Terrible Failure: Report a condition that should never happen. The
     * error will always be logged at level ASSERT with the call stack.
     * Depending on system configuration, a report may be added to the
     * {@link android.os.DropBoxManager} and/or the process may be terminated
     * immediately with an error dialog.
     * 
     * @param tag
     *            Used to identify the source of a log message.
     * @param msg
     *            The message you would like logged.
     */
    public static void wtf(String tag, String msg) {
        if (Log.ASSERT > DEBUG_LEVEL) {
            Log.wtf(tag, msg);
        }
    }

    /**
     * Send a {@link #VERBOSE} log message. And just print method name and
     * position in black.
     */
    public static void print() {
        if (Log.VERBOSE > DEBUG_LEVEL) {
            String tag = getClassName();
            String method = callMethodAndLine();
            Log.v(tag, method);
            if (DEBUG_SYSOUT) {
                System.out.println(tag + "  " + method);
            }
        }
    }

    /**
     * Send a {@link #DEBUG_LEVEL} log message.
     * 
     * @param object
     *            The object to print.
     */
    public static void print(Object object) {
        if (Log.DEBUG > DEBUG_LEVEL) {
            String tag = getClassName();
            String method = callMethodAndLine();
            String content = "";
            if (object != null) {
                content = object.toString() + "                    ----    "
                        + method;
            } else {
                content = " ## " + "                ----    " + method;
            }
            Log.d(tag, content);
            if (DEBUG_SYSOUT) {
                System.out.println(tag + "  " + content + "  " + method);
            }
        }
    }

    /**
     * Send an {@link #ERROR} log message.
     * 
     * @param object
     *            The object to print.
     */
    public static void printError(Object object) {
        if (Log.ERROR > DEBUG_LEVEL) {
            String tag = getClassName();
            String method = callMethodAndLine();
            String content = "";
            if (object != null) {
                content = object.toString() + "                    ----    "
                        + method;
            } else {
                content = " ## " + "                    ----    " + method;
            }
            Log.e(tag, content);
            if (DEBUG_SYSOUT) {
                System.err.println(tag + "  " + method + "  " + content);
            }
        }
    }

    /**
     * Print the array of stack trace elements of this method in black.
     * 
     * @return
     */
    public static void printCallHierarchy() {
        if (Log.VERBOSE > DEBUG_LEVEL) {
            String tag = getClassName();
            String method = callMethodAndLine();
            String hierarchy = getCallHierarchy();
            Log.v(tag, method + hierarchy);
            if (DEBUG_SYSOUT) {
                System.out.println(tag + "  " + method + hierarchy);
            }
        }
    }

    /**
     * Print debug log in blue.
     * 
     * @param object
     *            The object to print.
     */
    public static void printMyLog(Object object) {
        if (Log.DEBUG > DEBUG_LEVEL) {
            String tag = "MYLOG";
            String method = callMethodAndLine();
            String content = "";
            if (object != null) {
                content = object.toString() + "                    ----    "
                        + method;
            } else {
                content = " ## " + "                ----    " + method;
            }
            Log.d(tag, content);
            if (DEBUG_SYSOUT) {
                System.out.println(tag + "  " + content + "  " + method);
            }
        }
    }

    private static String getCallHierarchy() {
        String result = "";
        StackTraceElement[] trace = (new Exception()).getStackTrace();
        for (int i = 2; i < trace.length; i++) {
            result += "\r\t" + trace[i].getClassName() + "."
                    + trace[i].getMethodName() + "():"
                    + trace[i].getLineNumber();
        }
        return result;
    }

    private static String getClassName() {
        String result = "";
        StackTraceElement thisMethodStack = (new Exception()).getStackTrace()[2];
        result = thisMethodStack.getClassName();
        return result;
    }

    /**
     * Realization of double click jump events.
     * 
     * @return
     */
    private static String callMethodAndLine() {
        String result = "at ";
        StackTraceElement thisMethodStack = (new Exception()).getStackTrace()[2];
        result += thisMethodStack.getClassName() + ".";
        result += thisMethodStack.getMethodName();
        result += "(" + thisMethodStack.getFileName();
        result += ":" + thisMethodStack.getLineNumber() + ")  ";
        return result;
    }

}

获取更多请参看我 Github 分享的 Android 工具类库 android-utils 。

本文地址 http://94275.cn/2014/10/16/android-log/ 作者为 Zhenguo