{"id":346,"date":"2023-02-25T07:02:59","date_gmt":"2023-02-24T23:02:59","guid":{"rendered":"https:\/\/www.appblog.cn\/?p=346"},"modified":"2023-04-30T14:47:25","modified_gmt":"2023-04-30T06:47:25","slug":"android-custom-handler-use-static-inner-class-to-avoid-memory-leak","status":"publish","type":"post","link":"https:\/\/www.appblog.cn\/index.php\/2023\/02\/25\/android-custom-handler-use-static-inner-class-to-avoid-memory-leak\/","title":{"rendered":"Android\u81ea\u5b9a\u4e49Handler\u4f7f\u7528\u9759\u6001\u5185\u90e8\u7c7b\u907f\u514d\u5185\u5b58\u6cc4\u6f0f"},"content":{"rendered":"<p>\u5728Activity\u4e2d\u58f0\u660eHandler\u7c7b\u65f6\uff0cAndroid Studio\u4f1a\u63d0\u793a\u8b66\u544a\uff1a<\/p>\n<blockquote>\n<p>This Handler class should be static or leaks might occur<\/p>\n<\/blockquote>\n<p><!-- more --><\/p>\n<p>\u4f8b\u5982\u8fd9\u6837\u7684\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-java\">public class MainActivity extends Activity {\n\n    \/\/ This Handler class should be static or leaks might occur\n    class MyHandler extends Handler {\n        @Override\n        public void handleMessage(Message msg) {  }\n    }\n}<\/code><\/pre>\n<p>\u56e0\u4e3a\u5982\u679cHandler\u4f7f\u7528UI\u7ebf\u7a0b\u6765\u505a\u6d88\u606f\u5e8f\u5217\u7684\u5904\u7406\uff0c\u90a3\u4e48\u53ef\u80fd\u4f1a\u5bfc\u81f4Activity\u7c7b\u65e0\u6cd5\u88ab\u56de\u6536\uff0c\u7ee7\u800c\u5f15\u53d1\u5185\u5b58\u6cc4\u6f0f\u3002<\/p>\n<p>\u901a\u4fd7\u7684\u8bb2\uff0c\u8017\u65f6\u5185\u90e8\u7c7b\u5f15\u7528\u5916\u90e8\u7c7b\uff0c\u53ef\u80fd\u5bfc\u81f4\u5916\u90e8\u7c7b\u65e0\u6cd5\u56de\u6536<\/p>\n<p>\u56e0\u6b64\u6309\u7167\u8b66\u544a\u4e2d\u7684\u63d0\u793a\uff0cHandler\u5e94\u58f0\u660e\u4e3a\u9759\u6001\u5185\u90e8\u7c7b:<\/p>\n<pre><code class=\"language-java\">public class MainActivity extends Activity {\n\n    static class MyHandler extends Handler {\n        @Override\n        public void handleMessage(Message msg) {  }\n    }\n}<\/code><\/pre>\n<p>\u58f0\u660e\u4e3a\u9759\u6001\u7c7b\u4ee5\u540e\uff0cHandler\u5c31\u6ca1\u6709\u4e86Activity\u7684\u5f15\u7528\uff0c\u65e0\u6cd5\u76f4\u63a5\u5f15\u7528\u5176\u53d8\u91cf\u6216\u65b9\u6cd5\u4e86\uff0c\u56e0\u6b64\u6211\u4eec\u5728\u8fd9\u91cc\u4f7f\u7528\u5f31\u5f15\u7528WeakReference\u6765\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff1a<\/p>\n<pre><code class=\"language-java\">static class MyHandler extends Handler {\n\n    WeakReference&lt;MainActivity&gt; activity;\n\n    public DownloadHandler(MainActivity mainActivity) {\n        activity = new WeakReference&lt;MainActivity&gt;(mainActivity);\n    }\n\n    @Override\n    public void handleMessage(Message msg) {  }\n}<\/code><\/pre>\n<p>WeakReference\u53ef\u4ee5\u5c3d\u65e9\u5730\u88abGC\u56de\u6536\u6389\uff0c\u56e0\u6b64\u53ef\u4ee5\u9632\u6b62\u5185\u5b58\u6cc4\u6f0f\u3002\u7531\u4e8e\u8fd9\u91cc\u7684activity\u53d8\u91cf\u5b9e\u9645\u4e0d\u662fMainActivity\u7c7b\u578b\u7684\uff0c\u56e0\u6b64\u5728handleMessage\u4e2d\u8fd8\u8981\u591a\u4e00\u6b65\u83b7\u53d6\u4e0e\u5224\u65ad\uff1a<\/p>\n<pre><code class=\"language-java\">@Override\npublic void handleMessage(Message msg) {\n    if (activity.get() != null) {\n        activity.get().someMethod();\n    }\n}<\/code><\/pre>\n<p>\u5f53\u7136\u6bcf\u6b21\u8fd9\u6837\u8c03\u7528\u6bd4\u8f83\u9ebb\u70e6\uff0c\u53ef\u4ee5\u5c06WeakReference\u58f0\u660e\u521d\u59cb\u5316\u5728MainActivity\u4e2d\uff0c\u5728Handler\u521d\u59cb\u5316\u65f6\u76f4\u63a5\u4f20\u5165\uff1a<\/p>\n<pre><code class=\"language-java\">public class MainActivity extends Activity {\n\n    WeakReference&lt;MainActivity&gt; activity;\n    MyHandler mHandler;\n\n    @Override\n    protected void onCreate(Bundle savedInstanceState) {\n        activity = new WeakReference&lt;MainActivity&gt;(mainActivity);\n        mHandler = new MyHandler(activity);\n    }\n\n    class MyHandler extends Handler {\n        private MainActivity activity;\n\n        public MyHandler(WeakReference&lt;MainActivity&gt; ref) {\n            activity = ref.get();\n        }\n\n        @Override\n        public void handleMessage(Message msg) {\n            if(activity != null) {\n                activity.someMethod();\n            }\n        }\n    }\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u5728Activity\u4e2d\u58f0\u660eHandler\u7c7b\u65f6\uff0cAndroid Studio\u4f1a\u63d0\u793a\u8b66\u544a\uff1a This Handler [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[61],"tags":[121],"class_list":["post-346","post","type-post","status-publish","format-standard","hentry","category-android-basic","tag-handler"],"_links":{"self":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/346","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/comments?post=346"}],"version-history":[{"count":0,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/346\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/media?parent=346"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/categories?post=346"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/tags?post=346"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}