Android内存泄露自动检测神器LeakCanary

经典的面试题：

a、怎样在coding过程中避免内存泄露？

b、怎样检测内存泄露？

这两个问题我想大部分Android 职位面试时都会被问到吧。

怎样避免就不赘述了，网上很多答案。

工具呢，当然也有很多，比如DDMS、MAT等，但是怎样在我们编码过程中植入内存检测代码，让我们程序在开发调试阶段就能发现内存泄露呢？好了，现在该大名鼎鼎的LeakCanary出场了，它是Square公司的一个内存探测开源项目。下面就介绍下怎样使用.

1、配置gradle依赖:

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debugCompile 'com.squareup.leakcanary:leakcanary-android:1.3.1'

releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.3.1'

2、初始化Watcher

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package com.micky.leakcanarysamples;;

import android.app.Application;

import com.squareup.leakcanary.LeakCanary;

import com.squareup.leakcanary.RefWatcher;

/**

* @Project LeakCanaryTest

* @Packate com.micky.leakcanarysamples;

* @Description

* @Author Micky Liu

* @Email mickyliu@126.com

* @Date 2016-01-04 10:32

* @Version 1.0

*/

public class BaseApplication extends Application {

private static BaseApplication instance;

private RefWatcher mRefWatcher;

@Override

public void onCreate() {

super.onCreate();

instance = this;

mRefWatcher = Constants.DEBUG ? LeakCanary.install(this) : RefWatcher.DISABLED;

}

public static BaseApplication getInstance() {

return instance;

}

public static RefWatcher getRefWatcher() {

return getInstance().mRefWatcher;

}

}

3、在Activity或Fragment中添加检测

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package com.micky.leakcanarysamples;

import android.app.Activity;

import android.support.v7.app.AppCompatActivity;

/**

* @Project LeakCanaryTest

* @Packate com.micky.leakcanarysamples;

* @Description

* @Author Micky Liu

* @Email mickyliu@126.com

* @Date 2016-01-04 10:39

* @Version 1.0

*/

public class BaseActivity extends AppCompatActivity {

@Override

protected void onDestroy() {

super.onDestroy();

BaseApplication.getRefWatcher().watch(this);

}

}

4、测试

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package com.micky.leakcanarysamples;;

import android.os.Bundle;

import android.os.Handler;

/**

* @Project LeakCanaryTest

* @Packate com.micky.leakcanarysamples;

* @Description

* @Author Micky Liu

* @Email mickyliu@126.com

* @Date 2016-01-04 10:29

* @Version 1.0

*/

public class TestActivity extends BaseActivity {

private final Handler mHandler = new Handler();

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

//模拟内存泄露

mHandler.postDelayed(new Runnable() {

@Override

public void run() {

}

}, 3 * 60 * 1000);

finish();

}

}

5、测试结果

a、Toast显示（大概10秒左右显示）



b、通知显示



c、桌面自动添加的图表



d、内存泄露列表



e、内存泄露详细



LogCat可以看到日志日下（hprof文件可以用MAT打开进行分析）：

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01-04 11:49:41.815 12967-13004/com.micky.leakcanarysamples I/dalvikvm: hprof: dumping heap strings to "/storage/emulated/0/Download/leakcanary/suspected_leak_heapdump.hprof".

01-04 11:49:42.020 12967-13004/com.micky.leakcanarysamples I/dalvikvm: hprof: heap dump completed (28850KB)

查看自动生成的AndroidManifest文件，LeakCanarySamples/app/build/intermediates/manifests/full/debug/AndroidManifest.xml

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<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.micky.leakcanarysamples"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="10"

android:targetSdkVersion="23" />

<!-- To store the heap dumps and leak analysis results. -->

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<android:uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

<application

android:name="com.micky.leakcanarysamples.BaseApplication"

android:allowBackup="true"

android:icon="@mipmap/ic_launcher"

android:label="@string/app_name"

android:supportsRtl="true"

android:theme="@style/AppTheme" >

<activity

android:name="com.micky.leakcanarysamples.MainActivity"

android:label="@string/app_name"

android:theme="@style/AppTheme.NoActionBar" >

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

<activity android:name="com.micky.leakcanarysamples.TestActivity" />

<service

android:name="com.squareup.leakcanary.internal.HeapAnalyzerService"

android:enabled="false"

android:process=":leakcanary" />

<service

android:name="com.squareup.leakcanary.DisplayLeakService"

android:enabled="false" />

<activity

android:name="com.squareup.leakcanary.internal.DisplayLeakActivity"

android:enabled="false"

android:icon="@drawable/__leak_canary_icon"

android:label="@string/__leak_canary_display_activity_label"

android:taskAffinity="com.squareup.leakcanary"

android:theme="@style/__LeakCanary.Base" >

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

</application>

</manifest>

如上所示LeakCanary给我们自动添加了两个Service和一个Activity，并添加了对SD卡的读写权限

It 's so simple.
注:

1、如果在Release模式下请使用RefWatcher.DISABLED

2、在Activity或Fragment 的 Destroy方法中添加检测（很好理解，就是判断一个Activity或Fragment想要被销毁的时候，是否还有其他对象持有其引用导致Activity或Fragment不能被回收，从而导致内存泄露)

源码地址:https://github.com/mickyliu945/LeakCanarySample 点击打开链接