{"id":120,"date":"2022-04-14T08:18:35","date_gmt":"2022-04-14T08:18:35","guid":{"rendered":"http:\/\/www.devblog.cn\/?p=120"},"modified":"2025-03-03T17:56:09","modified_gmt":"2025-03-03T09:56:09","slug":"120","status":"publish","type":"post","link":"http:\/\/www.devblog.cn\/?p=120","title":{"rendered":"Android-Handler\u6e90\u7801\u89e3\u6790-Message\uff08\u56db\uff09"},"content":{"rendered":"<h1>Android-Handler\u6e90\u7801\u89e3\u6790-Message\uff08\u56db\uff09<\/h1>\n<blockquote><p>\n  \u6e90\u7801\u7248\u672c\uff1a<br \/>\n  * <strong>Handler<\/strong>\uff1aSDK-35<br \/>\n  * <strong>\u66f4\u65b0\u65f6\u95f4<\/strong>\uff1a2025-3\u6708<\/p>\n<p>  <strong>\u5bfc\u822a\uff1a<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/juejin.cn\/post\/7475656733558652943\">Android-Handler\u6e90\u7801\u89e3\u6790-\u4f7f\u7528<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085976728538972190\">Android-Handler\u6e90\u7801\u89e3\u6790-Handler\uff08\u4e00\uff09<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085976341056585742\">Android-Handler\u6e90\u7801\u89e3\u6790-Looper\uff08\u4e8c\uff09<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085977128092565512\">Android-Handler\u6e90\u7801\u89e3\u6790-MessageQueue\uff08\u4e09\uff09<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085975951414132766\">Android-Handler\u6e90\u7801\u89e3\u6790-Message\uff08\u56db\uff09<\/a><\/li>\n<li>\u66f4\u591a\u7684\u6587\u7ae0\u770b\u8fd9\u91cc\uff1a<a href=\"https:\/\/juejin.cn\/user\/4450479132652679\/posts\">\u4e3b\u9875<\/a><\/li>\n<\/ul>\n<\/blockquote>\n<h2>\u6210\u5458\u53d8\u91cf<\/h2>\n<pre><code class=\"language-java\">\/\/ \u6807\u8bc6Message\npublic int what;\n\n\/\/ \u5b58\u50a8\u7b80\u5355\u6570\u636e\uff0c\u5982\u679c\u5b58\u50a8\u590d\u6742\u7684\u6570\u636e\u4f7f\u7528setData()\u65b9\u6cd5\u3002\npublic int arg1;\npublic int arg2;\n\n\/\/ \u53d1\u9001\u7ed9\u63a5\u6536\u8005\u7684\u4efb\u610f\u5bf9\u8c61\u3002\npublic Object obj;\n\n\/\/ \u56de\u590d\u7ed9\u53d1\u9001\u8005\uff0c\u7528\u4e8e\u8de8\u8fdb\u7a0b\u53cc\u5411\u901a\u4fe1\u3002\u53d1\u9001\u65b9\u8fdb\u7a0b\u7ed9\u5176replyTo\u8d4b\u503c\uff0c\u63a5\u6536\u65b9\u8fdb\u7a0b\u53ef\u4ee5\u901a\u8fc7message.replyTo\u5411\u53d1\u9001\u65b9\u8fdb\u7a0b\u53d1\u9001message\uff0c\u4ece\u800c\u5b9e\u73b0\u53cc\u5411\u901a\u4fe1\u3002\npublic Messenger replyTo;\n\npublic static final int UID_NONE = -1;\n\/\/ \u53ef\u9009\u5b57\u6bb5\uff0c\u8868\u793a\u53d1\u9001\u6d88\u606f\u7684uid\u3002\u8fd9\u53ea\u5bf9Messenger\u53d1\u5e03\uff08\u8de8\u8fdb\u7a0b\u53d1\u5e03\uff09\u7684\u6d88\u606f\u6709\u6548\uff1b\u5426\u5219\uff0c\u5b83\u5c31\u662f-1\u3002\npublic int sendingUid = UID_NONE;\n\/\/ \u53ef\u9009\u5b57\u6bb5\uff0c\u6307\u793a\u5bfc\u81f4\u8be5\u6d88\u606f\u8fdb\u5165\u961f\u5217\u7684uid\u3002\npublic int workSourceUid = UID_NONE;\n\n\/\/ \u5728\u7528\u6807\u8bb0\n\/*package*\/ static final int FLAG_IN_USE = 1 &lt;&lt; 0;\n\/\/ \u5f02\u6b65\u6807\u8bb0\n\/*package*\/ static final int FLAG_ASYNCHRONOUS = 1 &lt;&lt; 1;\n\/\/ copy\u7684\u6e05\u7a7a\u6807\u8bb0\n\/*package*\/ static final int FLAGS_TO_CLEAR_ON_COPY_FROM = FLAG_IN_USE;\n\/\/ \u6807\u8bb0\u4f4d\n@UnsupportedAppUsage\n\/*package*\/ int flags;\n\n\/\/ \u6267\u884c\u65f6\u523b\uff0c\u65f6\u523b\u57fa\u4e8eSystemClock.uptimeMillis\u3002\n@UnsupportedAppUsage\npublic long when;\n\n\/\/ \u5b58\u50a8\u590d\u6742\u7684\u6570\u636e\n\/*package*\/ Bundle data;\n\n\/\/ \u6d88\u606f\u7684\u76ee\u6807\u5904\u7406\u5668Handler\uff0c\u5373\u7531\u6b64Handler\u5904\u7406\u6b64\u6d88\u606f\u3002\n@UnsupportedAppUsage\n\/*package*\/ Handler target;\n\n\/\/ \u8868\u793a\u8981\u5904\u7406\u7684\u4efb\u52a1Callback\uff0c\u7531Runnable\u5b9e\u73b0\uff0c\u901a\u8fc7handler.post Runnable\u7684\u65f6\u5019\uff0cRunnable\u4f1a\u88ab\u5b58\u653e\u5728Message\u4e2d\uff0c\u5206\u53d1\u7684\u65f6\u5019\u518d\u8fdb\u884c\u56de\u8c03\u901a\u77e5\u3002\n@UnsupportedAppUsage\n\/*package*\/ Runnable callback;\n\n\/\/ \u4e0b\u4e2a\u6d88\u606f\uff0c\u7528\u4e8e\u5b9e\u73b0\u94fe\u8868\u7ed3\u6784\u3002\n@UnsupportedAppUsage\n\/*package*\/ Message next;\n\n\/\/ \u6d88\u606f\u6c60\u7684\u540c\u6b65\u9501\u5bf9\u8c61\uff0c\u7528\u6237\u6d88\u606f\u6c60\u7684\u6d88\u606f\u83b7\u53d6\uff08obtain()\u65b9\u6cd5\uff09\u548c\u6d88\u606f\u56de\u6536\uff08recycleUnchecked()\u65b9\u6cd5\uff09\u3002\n\/** @hide *\/\npublic static final Object sPoolSync = new Object();\n\/\/ \u6d88\u606f\u6c60\u94fe\u8868\u7684\u5934\uff0c\u7528\u4e8e\u64cd\u4f5c\uff08\u589e\u5220\u6539\u67e5\uff09\u94fe\u8868\u3002\nprivate static Message sPool;\n\/\/ \u6d88\u606f\u6c60\u4e2d\u6d88\u606f\u7684\u6570\u91cf\nprivate static int sPoolSize = 0;\n\/\/ \u6d88\u606f\u6c60\u4e2d\u6d88\u606f\u7684\u6700\u5927\u6570\u91cf\uff0c\u4e3a50\u4e2a\u3002\nprivate static final int MAX_POOL_SIZE = 50;\n\/\/ \u662f\u5426\u68c0\u67e5\u6d88\u606f\u7684\u56de\u6536\uff08recycle()\u65b9\u6cd5\uff09\uff0c\u9ed8\u8ba4true\uff0c\u5982\u679c\u68c0\u67e5\u5e76\u4e14\u6709\u95ee\u9898\uff0c\u5219\u629b\u51fa\u5f02\u5e38\u3002\nprivate static boolean gCheckRecycle = true;\n<\/code><\/pre>\n<blockquote><p>\n  \u8bf4\u660e\uff1a<br \/>\n  1. <code>Handler<\/code>\u76f8\u5173\u4ecb\u7ecd\uff0c\u8bf7\u770b<a href=\"https:\/\/juejin.cn\/post\/7085976728538972190\">Android-Handler\u6e90\u7801\u89e3\u6790-Handler<\/a>\u3002<br \/>\n  1. <code>Message<\/code>\u4e3a\u4ec0\u4e48\u9700\u8981\u6301\u6709<code>Handler<\/code>\uff0c\u56e0\u4e3a<code>Message<\/code>\u9700\u8981\u77e5\u9053\u662f\u54ea\u4e2a<code>Handler<\/code>\u8981\u5904\u7406\u5b83\u3002\n<\/p><\/blockquote>\n<h2>\u521b\u5efaMessage<\/h2>\n<p>\u60f3\u8981<strong>\u4f7f\u7528<\/strong>\u3001<strong>\u53d1\u9001<\/strong><code>Message<\/code>\uff0c\u9996\u5148\u8981<strong>\u521b\u5efa<\/strong><code>Message<\/code>\uff0c\u6240\u4ee5\u6211\u4eec\u63a5\u4e0b\u6765\u770b\u4e0b\u5b83\u662f\u5982\u4f55\u88ab<strong>\u521b\u5efa<\/strong>\u7684\u3002<\/p>\n<h3>new Message()<\/h3>\n<pre><code class=\"language-java\">public Message() {\n}\n<\/code><\/pre>\n<p><strong>\u76f4\u63a5\u521b\u5efa<\/strong>\u4e00\u4e2a<code>Message<\/code>\u5bf9\u8c61\uff0c\u4e4b\u540e\u53ef\u4ee5\u8bbe\u7f6e\u5b83\u7684<strong>\u5c5e\u6027<\/strong>\uff0c\u672a\u4f7f\u7528<strong>\u590d\u7528<\/strong>\uff0c<strong>\u4e0d\u63a8\u8350<\/strong>\u4f7f\u7528\u3002<\/p>\n<h3>Message.obtain()<\/h3>\n<p><strong>Message.obtain()<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain() {\n    \/\/ \u4f7f\u7528\u540c\u6b65\u4fdd\u8bc1\u7ebf\u7a0b\u5b89\u5168\uff0c\u56e0\u4e3a\u6b64\u65b9\u6cd5\u53ef\u4ee5\u5728\u4efb\u610f\u7ebf\u7a0b\u8c03\u7528\u3002\n    synchronized (sPoolSync) {\n        if (sPool != null) {\n            \/\/ \u6d88\u606f\u6c60\u5934\u4e0d\u4e3a\u7a7a\uff0c\u8bf4\u660e\u961f\u5217\u6709\u5185\u5bb9\uff0c\u4ece\u4e2d\u83b7\u53d6\u4e00\u6761\u6d88\u606f\u5e76\u8fd4\u56de\u3002\u7f13\u5b58\u7684\n            Message m = sPool; \/\/ \u6d88\u606f\u6c60\u7684Head\u5143\u7d20\n            sPool = m.next; \/\/ \u7f13\u5b58\u6c60Head\u4e3a\u4e0b\u4e2a\u5143\u7d20\uff08\u79fb\u9664m\uff09\n            m.next = null; \/\/ \u65ad\u5f00\u94fe\u63a5\n            m.flags = 0; \/\/ \u6e05\u9664\u5728\u7528\u6807\u8bb0\n            sPoolSize--; \/\/ \u6c60\u6570\u91cf\u51cf1\n            return m; \/\/ \u8fd4\u56de\u6b64\u6d88\u606f\n        }\n    }\n    \/\/ \u6d88\u606f\u6c60\u5934\u4e3a\u7a7a\uff0c\u8bf4\u660e\u961f\u5217\u6ca1\u6709\u5185\u5bb9\uff0c\u76f4\u63a5\u521b\u5efa\u4e00\u6761\u6d88\u606f\u5e76\u8fd4\u56de\u3002\n    return new Message();\n}\n<\/code><\/pre>\n<p><code>Message.obtain()<\/code>\u4e3a<strong>\u9759\u6001<\/strong>\u65b9\u6cd5\uff0c\u5185\u90e8\u7528\u4e86<strong>\u5168\u5c40\u6d88\u606f\u6c60<\/strong>\uff0c\u4f7f\u7528\u4e86<strong>\u590d\u7528<\/strong>\uff0c<strong>\u63a8\u8350<\/strong>\u4f7f\u7528\u3002<\/p>\n<blockquote><p>\n  \u8bf4\u660e\uff1a<br \/>\n  1. \u4ece<strong>\u6d88\u606f\u6c60<\/strong>\u4e2d<strong>\u83b7\u53d6\u6d88\u606f<\/strong>\uff0c\u5b83\u4f1a\u83b7\u53d6<strong>\u961f\u5217<\/strong>\u7684<strong>\u7b2c\u4e00\u6761<\/strong>\u6d88\u606f\uff0c\u5e76\u5c06<strong>\u6b64\u6d88\u606f<\/strong>\u4ece<strong>\u6b64\u961f\u5217<\/strong>\u4e2d<strong>\u79fb\u9664<\/strong>\u3002\n<\/p><\/blockquote>\n<p><strong>Message.obtain(Message)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Message orig) {\n    \/\/ \u83b7\u53d6\u6d88\u606f\n    Message m = obtain();\n    \/\/ \u5c06orig\u7684\u503c\u590d\u5236\u5230\u65b0\u6d88\u606f\u4e2d\n    m.what = orig.what;\n    m.arg1 = orig.arg1;\n    m.arg2 = orig.arg2;\n    m.obj = orig.obj;\n    m.replyTo = orig.replyTo;\n    m.sendingUid = orig.sendingUid;\n    m.workSourceUid = orig.workSourceUid;\n    if (orig.data != null) {\n        m.data = new Bundle(orig.data);\n    }\n    m.target = orig.target;\n    m.callback = orig.callback;\n\n    return m;\n}\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u5c06<strong>\u73b0\u6709<\/strong><code>Message<\/code>(\u5305\u62ec\u5176<code>target<\/code>)\u7684\u503c<strong>\u590d\u5236<\/strong>\u5230<strong>\u65b0\u7684\u6d88\u606f<\/strong>\u4e2d\u3002<\/p>\n<p><strong>Message.obtain(Handler)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Handler h) {\n    Message m = obtain();\n    m.target = h;\n\n    return m;\n}\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u8bbe\u7f6e\u4e86<code>target<\/code>\u6210\u5458\u7684\u503c\u3002<\/p>\n<p><strong>Message.obtain(Handler, Runnable)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Handler h, Runnable callback) {\n    Message m = obtain();\n    m.target = h;\n    m.callback = callback;\n\n    return m;\n}\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u8bbe\u7f6e\u4e86<code>target<\/code>\u548c<code>callback<\/code>\u6210\u5458\u7684\u503c\u3002<\/p>\n<p><strong>Message.obtain(Handler, int)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Handler h, int what) {\n    Message m = obtain();\n    m.target = h;\n    m.what = what;\n\n    return m;\n}Message.\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u8bbe\u7f6e\u4e86<code>target<\/code>\u548c<code>what<\/code>\u6210\u5458\u7684\u503c\u3002<\/p>\n<p><strong>Message.obtain(Handler, int, Object)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Handler h, int what, Object obj) {\n    Message m = obtain();\n    m.target = h;\n    m.what = what;\n    m.obj = obj;\n\n    return m;\n}\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u8bbe\u7f6e\u4e86<code>target<\/code>\u3001<code>what<\/code>\u548c<code>obj<\/code>\u6210\u5458\u7684\u503c\u3002<\/p>\n<p><strong>Message.obtain(Handler, int, int, int)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Handler h, int what, int arg1, int arg2) {\n    Message m = obtain();\n    m.target = h;\n    m.what = what;\n    m.arg1 = arg1;\n    m.arg2 = arg2;\n\n    return m;\n}\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u8bbe\u7f6e\u4e86<code>target<\/code>\u3001<code>what<\/code>\u3001<code>arg1<\/code>\u548c<code>arg2<\/code>\u6210\u5458\u7684\u503c\u3002<\/p>\n<p><strong>Message.obtain(Handler, int, int, int, Object)<\/strong><\/p>\n<pre><code class=\"language-java\">public static Message obtain(Handler h, int what,\n        int arg1, int arg2, Object obj) {\n    Message m = obtain();\n    m.target = h;\n    m.what = what;\n    m.arg1 = arg1;\n    m.arg2 = arg2;\n    m.obj = obj;\n\n    return m;\n}\n<\/code><\/pre>\n<p>\u4e0e<code>Message.obtain()<\/code>\u76f8\u540c\uff0c\u4f46\u8bbe\u7f6e\u4e86<code>target<\/code>\u3001<code>what<\/code>\u3001<code>arg1<\/code>\u3001<code>arg2<\/code>\u548c<code>obj<\/code>\u6210\u5458\u7684\u503c\u3002<\/p>\n<h3>\u5c0f\u7ed3<\/h3>\n<blockquote>\n<ol>\n<li><code>Message<\/code>\u7684<strong>\u521b\u5efa<\/strong>\uff0c\u6709\u4e24\u79cd\u65b9\u5f0f\uff1a<code>new Message<\/code>\u3001<code>Message.obtain()<\/code>\uff0c<code>Message.obtain()<\/code>\u5185\u90e8\u4f7f\u7528\u4e86<strong>\u590d\u7528<\/strong>\uff0c<strong>\u63a8\u8350\u4f7f\u7528<\/strong>\u3002<\/li>\n<\/ol>\n<\/blockquote>\n<h2>\u56de\u6536Message<\/h2>\n<p>\u7531\u4e8e<code>Message.obtain()<\/code>\u65b9\u5f0f<strong>\u521b\u5efa<\/strong>\u5185\u90e8\u4f7f\u7528\u4e86<strong>\u590d\u7528<\/strong>\uff0c\u6240\u4ee5\u6211\u4eec\u63a5\u4e0b\u6765\u770b\u4e0b\u5b83\u662f\u5982\u4f55\u88ab<strong>\u56de\u6536<\/strong>\u7684\u3002<\/p>\n<h3>recycle()<\/h3>\n<pre><code class=\"language-java\">public void recycle() {\n    \/\/ \u5224\u65ad\u662f\u5426\u5728\u4f7f\u7528\u4e2d\n    if (isInUse()) {\n        \/\/ \u5728\u4f7f\u7528\u4e2d\uff0c\u76f4\u63a5\u8fd4\u56de\uff0c\u4e0d\u8fdb\u884c\u56de\u6536\u3002\n        if (gCheckRecycle) {\n            \/\/ gCheckRecycle\u4e3atrue\uff0c\u4e3a\u68c0\u67e5\u6d88\u606f\u7684\u56de\u6536\uff0c\u5e76\u4e14\u56de\u6536\u65f6\u6b63\u5728\u4f7f\u7528\uff08\u6709\u95ee\u9898\uff09\uff0c\u5219\u629b\u51fa\u5f02\u5e38\u3002\n            throw new IllegalStateException(\"This message cannot be recycled because it \"\n                    + \"is still in use.\");\n        }\n        return;\n    }\n    \/\/ \u4e0d\u5728\u4f7f\u7528\u4e2d\uff0c\u8fdb\u884c\u56de\u6536\u3002\n    recycleUnchecked();\n}\n<\/code><\/pre>\n<p><code>recycle()<\/code>\u65b9\u6cd5\uff0c\u4e3a<strong>\u68c0\u67e5<\/strong>\u56de\u6536\uff0c\u5982\u679c<strong>\u6b64\u6d88\u606f<\/strong>\u5904\u4e8e<strong>\u4f7f\u7528<\/strong>\u72b6\u6001\uff0c\u5219<strong>\u629b\u51fa\u5f02\u5e38<\/strong>\uff0c<strong>\u5426\u5219<\/strong>\u8c03\u7528<code>recycleUnchecked()<\/code><strong>\u76f4\u63a5\u8fdb\u884c\u56de\u6536<\/strong>\u3002<\/p>\n<p><code>isInUse()<\/code>\u65b9\u6cd5\u7684\u4f7f\u7528\u770b\u540e\u9762-<a href=\"#inuse\">\u5176\u5b83-InUse<\/a>\uff0c\u6211\u4eec\u63a5\u4e0b\u6765\u770b\u4e0b<code>gCheckRecycle<\/code>\u5c5e\u6027\uff0c\u5b83\u5728<code>updateCheckRecycle()<\/code>\u65b9\u6cd5\u5185\u8fdb\u884c<strong>\u66f4\u6539<\/strong>\u3002<\/p>\n<pre><code class=\"language-java\">public static void updateCheckRecycle(int targetSdkVersion) {\n    if (targetSdkVersion &lt; Build.VERSION_CODES.LOLLIPOP) {\n        \/\/ \u5c0f\u4e8eSDK 21\uff0c\u4e3afalse\u3002\n        gCheckRecycle = false;\n    }\n}\n<\/code><\/pre>\n<p><code>updateCheckRecycle()<\/code>\u65b9\u6cd5\uff0c\u4e3a<strong>\u66f4\u65b0<\/strong><code>gCheckRecycle<\/code>\u7684<strong>\u503c<\/strong>\u3002<code>gCheckRecycle<\/code>\u9ed8\u8ba4\u4e3a<code>true<\/code>\uff0c<code>updateCheckRecycle()<\/code>\u65b9\u6cd5\u5728<code>ActivityThread<\/code>\u7684<code>handleBindApplication()<\/code>\u65b9\u6cd5\uff08\u7ed1\u5b9aApp\uff09\u5185<strong>\u8c03\u7528<\/strong>\uff0c\u5373<code>gCheckRecycle<\/code>\u5728<code>targetSdkVersion<\/code><strong>\u5c0f\u4e8e<\/strong><code>21<\/code>\u4e3a<code>false<\/code>\uff08\u4e0d\u68c0\u67e5\uff09\uff0c<strong>\u5927\u4e8e\u3001\u7b49\u4e8e<\/strong><code>21<\/code>\u4e3a<code>ture<\/code>\uff08\u68c0\u67e5\uff09\u3002<\/p>\n<h3>recycleUnchecked()<\/h3>\n<pre><code class=\"language-java\">void recycleUnchecked() {\n    \/\/ \u5c06\u6b64\u6d88\u606f\u6807\u8bb0\u4e3a\u5728\u7528\uff0c\u5e76\u5224\u65ad\u662f\u5426\u6dfb\u52a0\u5230\u6d88\u606f\u6c60\u4e2d\u3002\n    \/\/ \u6e05\u9664\u6240\u6709\u5c5e\u6027\n    flags = FLAG_IN_USE;\n    what = 0;\n    arg1 = 0;\n    arg2 = 0;\n    obj = null;\n    replyTo = null;\n    sendingUid = UID_NONE;\n    workSourceUid = UID_NONE;\n    when = 0;\n    target = null;\n    callback = null;\n    data = null;\n\n    \/\/ \u540c\u6b65\uff0c\u4fdd\u8bc1\u7ebf\u7a0b\u5b89\u5168\u3002\n    synchronized (sPoolSync) {\n        if (sPoolSize &lt; MAX_POOL_SIZE) {\n            \/\/ \u5c0f\u4e8e\u6700\u5927\u503c\uff0c\u5219\u8fdb\u884c\u6dfb\u52a0\uff0c\u628a\u6b64Message\u6dfb\u52a0\u5230\u94fe\u8868\u7684\u5934\u90e8\u3002\n            next = sPool; \/\/ \u6b64Message\u7684next\u6307\u5411\u94fe\u8868\u7684Head\n            sPool = this; \/\/ \u94fe\u8868\u7684Head\u4e3a\u6b64Message\n            sPoolSize++; \/\/ \u6d88\u606f\u6c60\u6570\u91cf\u52a01\n        }\n    }\n}\n<\/code><\/pre>\n<p><code>recycleUnchecked()<\/code>\u65b9\u6cd5\uff0c\u4e3a<strong>\u4e0d\u68c0\u67e5<\/strong>\u56de\u6536\uff0c\u4f1a<strong>\u6e05\u9664\u6d88\u606f\u7684\u6240\u6709\u5c5e\u6027<\/strong>\uff0c\u4ee5\u5b8c\u6210<strong>\u91ca\u653e<\/strong>\uff0c\u5e76<strong>\u5224\u65ad<\/strong>\u5982\u679c<strong>\u6d88\u606f\u6c60<\/strong>\u7684<strong>\u6d88\u606f\u6570\u91cf<\/strong>\u6ca1\u6709\u5230\u8fbe<strong>\u6700\u5927\u6570\u91cf<\/strong>\uff0c\u5219\u8fdb\u884c<strong>\u6dfb\u52a0<\/strong>\uff0c\u4ee5\u5b8c\u6210<strong>\u56de\u6536<\/strong>\u3002<\/p>\n<blockquote><p>\n  \u8bf4\u660e\uff1a<br \/>\n  1. \u4ece<strong>\u6d88\u606f\u6c60<\/strong>\u4e2d<strong>\u6dfb\u52a0\u6d88\u606f<\/strong>\uff0c\u5b83\u4f1a\u5c06<strong>\u6b64\u6d88\u606f<\/strong>\u6dfb\u52a0\u5230<strong>\u961f\u5217<\/strong>\u7684<strong>\u5934\u90e8<\/strong>\uff0c\u5e76\u5c06<strong>\u6b64\u6d88\u606f<\/strong>\u4f5c\u4e3a<strong>\u65b0\u7684\u5934<\/strong>\u3002\n<\/p><\/blockquote>\n<h3>\u5c0f\u7ed3<\/h3>\n<blockquote>\n<ol>\n<li><code>Message<\/code>\u7684<strong>\u56de\u6536<\/strong>\uff0c\u6709\u4e24\u79cd\u65b9\u5f0f\uff1a<code>recycle()<\/code><strong>\u68c0\u67e5\u56de\u6536<\/strong>\u3001<code>recycleUnchecked()<\/code><strong>\u4e0d\u68c0\u67e5\u56de\u6536<\/strong>\u3002<\/li>\n<li><code>recycle()<\/code>\uff0c\u5224\u65ad\u4e86<strong>\u6d88\u606f<\/strong>\u5982\u679c\u5904\u4e8e<strong>\u4f7f\u7528<\/strong>\u72b6\u6001\uff0c\u5219<strong>\u4e0d\u8fdb\u884c\u56de\u6536<\/strong>\uff0c<strong>\u5426\u5219<\/strong>\u8c03\u7528<code>recycleUnchecked()<\/code><strong>\u8fdb\u884c\u56de\u6536<\/strong>\u3002<\/li>\n<li><code>recycleUnchecked()<\/code>\uff0c\u4f1a<strong>\u6e05\u9664\u6d88\u606f\u7684\u6240\u6709\u5c5e\u6027<\/strong>\uff0c\u5e76<strong>\u5224\u65ad<\/strong>\u5982\u679c<strong>\u6d88\u606f\u6c60\u6570\u91cf<\/strong>\u6ca1\u5230<strong>\u6d88\u606f\u6c60\u6700\u5927\u6570\u91cf<\/strong>\uff0c\u5219\u8fdb\u884c<strong>\u6dfb\u52a0<\/strong>\uff08\u6dfb\u52a0\u5230<strong>\u6d88\u606f\u6c60\u7684\u94fe\u8868<\/strong>\u7684<strong>\u5934\u90e8<\/strong>\uff09\u3002<\/li>\n<\/ol>\n<\/blockquote>\n<h2>\u5f02\u6b65Message<\/h2>\n<pre><code class=\"language-java\">public boolean isAsynchronous() {\n    return (flags &amp; FLAG_ASYNCHRONOUS) != 0;\n}\n<\/code><\/pre>\n<p><code>isAsynchronous()<\/code>\u65b9\u6cd5\uff0c\u5224\u65ad<strong>\u6d88\u606f<\/strong>\u662f\u5426\u662f<strong>\u5f02\u6b65<\/strong>\u7684\uff0c\u5982\u679c\u662f\uff0c\u5219\u8fd4\u56de<code>true<\/code>\u3002<\/p>\n<pre><code class=\"language-java\">public void setAsynchronous(boolean async) {\n    if (async) {\n        flags |= FLAG_ASYNCHRONOUS;\n    } else {\n        flags &amp;= ~FLAG_ASYNCHRONOUS;\n    }\n}\n<\/code><\/pre>\n<p><code>setAsynchronous()<\/code>\u65b9\u6cd5\uff0c\u8bbe\u7f6e<strong>\u6d88\u606f<\/strong>\u662f\u5426\u662f<strong>\u5f02\u6b65<\/strong>\u7684\uff0c\u8fd9\u610f\u5473\u7740\u5b83<strong>\u4e0d\u53d7<\/strong><code>Looper<\/code><strong>\u540c\u6b65\u5c4f\u969c<\/strong>\u7684\u5f71\u54cd\u3002<\/p>\n<blockquote><p>\n  \u8bf4\u660e\uff1a<\/p>\n<ol>\n<li><strong>\u6d88\u606f<\/strong>\uff0c\u5206\u4e3a<strong>\u540c\u6b65\u6d88\u606f<\/strong>\u548c<strong>\u5f02\u6b65\u6d88\u606f<\/strong>\uff0c<strong>\u9ed8\u8ba4<\/strong>\u4e3a<strong>\u540c\u6b65\u6d88\u606f<\/strong>\u3002<\/li>\n<li><strong>\u540c\u6b65\u5c4f\u969c<\/strong>\uff0c\u4f1a<strong>\u5c4f\u969c\u540c\u6b65\u6d88\u606f<\/strong>\uff0c\u786e\u4fdd<strong>\u53ea\u6709\u5f02\u6b65\u6d88\u606f<\/strong>\u6267\u884c\uff0c\u8be6\u7ec6\u8bf7\u770b<a href=\"https:\/\/juejin.cn\/post\/7085977128092565512\/#heading-8\">Android-Handler\u6e90\u7801\u89e3\u6790-MessageQueue-\u540c\u6b65\u5c4f\u969c<\/a>\u3002<\/li>\n<li>\u67d0\u4e9b\u64cd\u4f5c(\u6bd4\u5982<strong>\u89c6\u56fe\u5931\u6548<\/strong>)\u53ef\u80fd\u4f1a\u5728<code>Looper<\/code>\u7684<strong>\u6d88\u606f\u961f\u5217<\/strong>\u4e2d\u5f15\u5165<strong>\u540c\u6b65\u5c4f\u969c<\/strong>\uff0c\u4ee5<strong>\u963b\u6b62\u540e\u7eed\u6d88\u606f<\/strong>\u5728<strong>\u6ee1\u8db3\u67d0\u4e9b\u6761\u4ef6<\/strong>\u4e4b\u524d<strong>\u88ab\u4f20\u9012<\/strong>\u3002\u5728<code>view invalidation<\/code>\u7684\u60c5\u51b5\u4e0b\uff0c\u8c03\u7528<code>android.view.View.invalidate<\/code><strong>\u540e\u53d1\u5e03\u7684\u6d88\u606f<\/strong>\u4f1a\u88ab\u4e00\u4e2a<strong>\u540c\u6b65\u5c4f\u969c<\/strong>\u6302\u8d77\uff0c\u76f4\u5230\u4e0b\u4e00\u5e27\u51c6\u5907\u88ab\u7ed8\u5236\u3002<strong>\u540c\u6b65\u5c4f\u969c<\/strong>\u786e\u4fdd\u5728\u6062\u590d\u4e4b\u524d\u5b8c\u5168\u5904\u7406\u4e86<strong>\u65e0\u6548<\/strong>\u8bf7\u6c42\u3002<\/li>\n<li><strong>\u5f02\u6b65\u6d88\u606f<\/strong>\u514d\u4e8e<strong>\u540c\u6b65\u5c4f\u969c<\/strong>\u3002\u5b83\u4eec\u901a\u5e38\u8868\u793a<strong>\u4e2d\u65ad<\/strong>\u3001<strong>\u8f93\u5165\u4e8b\u4ef6<\/strong>\u548c<strong>\u5176\u5b83<\/strong>\u5fc5\u987b<strong>\u72ec\u7acb<\/strong>\u5904\u7406\u7684\u4fe1\u53f7\uff0c\u5373\u4f7f\u5176\u5b83\u5de5\u4f5c\u5df2\u7ecf\u6682\u505c\u3002<\/li>\n<li>\u8bf7\u6ce8\u610f\uff0c<strong>\u5f02\u6b65\u6d88\u606f<\/strong>\u53ef\u80fd\u662f\u6309<strong>\u540c\u6b65\u6d88\u606f<\/strong>\u7684<strong>\u987a\u5e8f\u4ea4\u4ed8<\/strong>\u7684\uff0c\u5c3d\u7ba1\u5b83\u4eec\u4e4b\u95f4<strong>\u603b\u662f\u6309\u987a\u5e8f\u4ea4\u4ed8<\/strong>\u7684\u3002\u5982\u679c\u8fd9\u4e9b\u6d88\u606f\u7684<strong>\u76f8\u5bf9\u987a\u5e8f\u5f88\u91cd\u8981<\/strong>\uff0c\u90a3\u4e48\u5b83\u4eec\u53ef\u80fd\u4e00\u5f00\u59cb\u5c31<strong>\u4e0d\u5e94\u8be5\u662f\u5f02\u6b65<\/strong>\u7684\uff0c<strong>\u8c28\u614e\u4f7f\u7528<\/strong>\u3002<\/li>\n<\/ol>\n<\/blockquote>\n<h2>\u8de8\u8fdb\u7a0b\u901a\u8baf<\/h2>\n<p>\u7531\u4e8e<code>Message<\/code>\u5b9e\u73b0\u4e86<code>Parcelable<\/code>\u63a5\u53e3\uff0c\u6240\u4ee5<code>Message<\/code>\u53ef\u4ee5<strong>\u8de8\u8fdb\u7a0b<\/strong>\u4f20\u8f93\uff0c\u6240\u4ee5\u6211\u4eec\u63a5\u4e0b\u6765\u770b\u4e0b\u5b83\u7684\u5177\u4f53\u5b9e\u73b0\u3002<\/p>\n<h3>writeToParcel()<\/h3>\n<pre><code class=\"language-java\">public void writeToParcel(Parcel dest, int flags) {\n    if (callback != null) {\n        \/\/ callback\u4e0d\u80fd\u8de8\u8fdb\u7a0b\u4f20\u8f93\uff0c\u629b\u51fa\u5f02\u5e38\u3002\n        throw new RuntimeException(\n            \"Can't marshal callbacks across processes.\");\n    }\n    dest.writeInt(what);\n    dest.writeInt(arg1);\n    dest.writeInt(arg2);\n    if (obj != null) {\n        \/\/ obj\u4e0d\u4e3a\u7a7a\uff0c\u8de8\u8fdb\u7a0b\u4f20\u8f93\u4efb\u610f\u5bf9\u8c61\uff0c\u5fc5\u987b\u5b9e\u73b0Parcelable\u63a5\u53e3\uff0c\u5426\u5219\u629b\u51fa\u5f02\u5e38\u3002\n        try {\n            Parcelable p = (Parcelable)obj;\n            dest.writeInt(1); \/\/ \u4f20\u51651\uff0c\u6807\u8bb0\u6709\u5b58\u5165obj\u5bf9\u8c61\u3002\n            dest.writeParcelable(p, flags); \/\/ \u5199\u5165obj\u5bf9\u8c61\n        } catch (ClassCastException e) {\n            throw new RuntimeException(\n                \"Can't marshal non-Parcelable objects across processes.\");\n        }\n    } else {\n        dest.writeInt(0); \/\/ \u4f20\u51650\uff0c\u6807\u8bb0\u6ca1\u6709\u5b58\u5165obj\u5bf9\u8c61\u3002\n    }\n    dest.writeLong(when);\n    dest.writeBundle(data);\n    Messenger.writeMessengerOrNullToParcel(replyTo, dest); \/\/ \u4f7f\u7528Messenger\u8fdb\u884c\u5199\u5165\n    dest.writeInt(sendingUid);\n    dest.writeInt(workSourceUid);\n}\n<\/code><\/pre>\n<h3>readFromParcel()<\/h3>\n<pre><code class=\"language-java\">private void readFromParcel(Parcel source) {\n    what = source.readInt();\n    arg1 = source.readInt();\n    arg2 = source.readInt();\n    if (source.readInt() != 0) {\n        \/\/ \u6709\u5b58\u5165obj\u5bf9\u8c61\uff0c\u8fdb\u884c\u8bfb\u53d6\u3002\n        obj = source.readParcelable(getClass().getClassLoader(), java.lang.Object.class);\n    }\n    when = source.readLong();\n    data = source.readBundle();\n    replyTo = Messenger.readMessengerOrNullFromParcel(source); \/\/ \u4f7f\u7528Messenger\u8fdb\u884c\u8bfb\u53d6\n    sendingUid = source.readInt();\n    workSourceUid = source.readInt();\n}\n<\/code><\/pre>\n<h3>\u5c0f\u7ed3<\/h3>\n<blockquote>\n<ol>\n<li><code>Message<\/code>\u7684<strong>\u8de8\u8fdb\u7a0b\u901a\u8baf<\/strong>\uff0c<code>callback<\/code>\u4e0d\u80fd\u6709\u503c\uff0c<code>obj<\/code><strong>\u5982\u6709\u503c<\/strong>\u5219<strong>\u5fc5\u987b<\/strong>\u5b9e\u73b0<code>Parcelable<\/code>\u63a5\u53e3\u3002<\/li>\n<\/ol>\n<\/blockquote>\n<h2>\u5c5e\u6027set\u3001get\u65b9\u6cd5<\/h2>\n<p><code>Message<\/code>\u7684<code>when<\/code>\u3001<code>target<\/code>\u3001<code>callback<\/code>\u3001<code>data<\/code>\u5c5e\u6027\u5bf9\u5916\u63d0\u4f9b\u4e86<code>set<\/code>\u3001<code>get<\/code>\u65b9\u6cd5\uff0c\u6211\u4eec\u63a5\u4e0b\u6765\u770b\u4e0b\u5b83\u4eec\u7684\u5b9e\u73b0\u3002<\/p>\n<h3>when<\/h3>\n<pre><code class=\"language-java\">public long getWhen() {\n    return when;\n}\n<\/code><\/pre>\n<h3>target<\/h3>\n<pre><code class=\"language-java\">public void setTarget(Handler target) {\n    this.target = target;\n}\n\npublic Handler getTarget() {\n    return target;\n}\n<\/code><\/pre>\n<h3>callback<\/h3>\n<pre><code class=\"language-java\">public Runnable getCallback() {\n    return callback;\n}\n<\/code><\/pre>\n<h3>data<\/h3>\n<pre><code class=\"language-java\">public Bundle getData() {\n    if (data == null) {\n        data = new Bundle();\n    }\n    return data;\n}\n\n@Nullable\npublic Bundle peekData() {\n    return data;\n}\n\npublic void setData(Bundle data) {\n    this.data = data;\n}\n<\/code><\/pre>\n<h2>\u5176\u5b83<\/h2>\n<h3>copyFrom()<\/h3>\n<pre><code class=\"language-java\">public void copyFrom(Message o) {\n    this.flags = o.flags &amp; ~FLAGS_TO_CLEAR_ON_COPY_FROM;\n    this.what = o.what;\n    this.arg1 = o.arg1;\n    this.arg2 = o.arg2;\n    this.obj = o.obj;\n    this.replyTo = o.replyTo;\n    this.sendingUid = o.sendingUid;\n    this.workSourceUid = o.workSourceUid;\n\n    if (o.data != null) {\n        this.data = (Bundle) o.data.clone();\n    } else {\n        this.data = null;\n    }\n}\n<\/code><\/pre>\n<p>\u5c06<strong>\u6307\u5b9a<\/strong><code>Message<\/code>\u7684\u5c5e\u6027\uff0c<strong>\u590d\u5236<\/strong>\u5230<strong>\u5f53\u524d<\/strong><code>Message<\/code>\u4e2d\u3002<\/p>\n<h3>sendToTarget()<\/h3>\n<pre><code class=\"language-java\">public void sendToTarget() {\n    target.sendMessage(this);\n}\n<\/code><\/pre>\n<p>\u5c06<strong>\u6b64\u6d88\u606f<\/strong>\u53d1\u9001\u7ed9<strong>\u81ea\u5df1<\/strong>\u7684<strong>\u76ee\u6807<\/strong><code>Handler<\/code>\uff0c\u5982\u679c<strong>\u672a\u8bbe\u7f6e<\/strong>\u6b64\u5b57\u6bb5\uff0c\u5219\u629b\u51fa<strong>\u7a7a\u6307\u9488<\/strong>\u5f02\u5e38\u3002<\/p>\n<h3>InUse<\/h3>\n<pre><code class=\"language-java\">\/*package*\/ boolean isInUse() {\n    return ((flags &amp; FLAG_IN_USE) == FLAG_IN_USE);\n}\n<\/code><\/pre>\n<p><code>isInUse()<\/code>\u65b9\u6cd5\uff0c\u5224\u65ad\u662f\u5426\u5904\u4e8e<strong>\u4f7f\u7528<\/strong>\u72b6\u6001\u3002<\/p>\n<pre><code class=\"language-java\">\/*package*\/ void markInUse() {\n    flags |= FLAG_IN_USE;\n}\n<\/code><\/pre>\n<p><code>markInUse()<\/code>\u65b9\u6cd5\uff0c\u6807\u8bb0\u5904\u4e8e<strong>\u4f7f\u7528<\/strong>\u72b6\u6001\u3002<\/p>\n<h1>\u603b\u7ed3<\/h1>\n<p>\u4ee5\u4e0a\u5c31\u662f<code>Handler<\/code>\u6e90\u7801\u7684<code>Message<\/code>\u90e8\u5206\uff0c<code>Handler<\/code>\u5176\u5b83\u6e90\u7801\u90e8\u5206\u770b\u4e0b\u9762<strong>\u5bfc\u822a<\/strong>\u3002\u6b22\u8fce\u5927\u5bb6<strong>\u70b9\u8d5e\u3001\u6536\u85cf<\/strong>\uff0c\u4ee5\u65b9\u4fbf\u60a8\u540e\u7eed\u67e5\u770b\uff0c\u4e4b\u540e\u4f1a\u51fa\u5176\u5b83<code>Android<\/code>\u6e90\u7801\u7cfb\u5217\uff0c\u8bf7\u53ca\u65f6\u5173\u6ce8\u3002\u5982\u679c\u4f60\u6709\u4ec0\u4e48\u95ee\u9898\uff0c\u53ef\u4ee5\u5728\u8bc4\u8bba\u533a\u7559\u8a00\uff01<\/p>\n<blockquote><p>\n  <strong>\u5bfc\u822a\uff1a<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/juejin.cn\/post\/7475656733558652943\">Android-Handler\u6e90\u7801\u89e3\u6790-\u4f7f\u7528<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085976728538972190\">Android-Handler\u6e90\u7801\u89e3\u6790-Handler\uff08\u4e00\uff09<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085976341056585742\">Android-Handler\u6e90\u7801\u89e3\u6790-Looper\uff08\u4e8c\uff09<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085977128092565512\">Android-Handler\u6e90\u7801\u89e3\u6790-MessageQueue\uff08\u4e09\uff09<\/a><\/li>\n<li><a href=\"https:\/\/juejin.cn\/post\/7085975951414132766\">Android-Handler\u6e90\u7801\u89e3\u6790-Message\uff08\u56db\uff09<\/a><\/li>\n<li>\u66f4\u591a\u7684\u6587\u7ae0\u770b\u8fd9\u91cc\uff1a<a href=\"https:\/\/juejin.cn\/user\/4450479132652679\/posts\">\u4e3b\u9875<\/a><\/li>\n<\/ul>\n<\/blockquote>\n<p>\u6700\u540e\u63a8\u8350\u4e00\u4e0b\u6211\u7684\u7f51\u7ad9\uff0c\u5f00\u53d1\u8005\uff08<code>Developer<\/code>\uff09\u7684\u535a\u5ba2\uff08<code>Blog<\/code>\uff09: <a href=\"http:\/\/www.devblog.cn\/\">devblog.cn<\/a> \uff0c\u6b22\u8fce\u5927\u5bb6\u6765\u4f53\u9a8c\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Android-Handler\u6e90\u7801\u89e3\u6790-Message\uff08\u56db\uff09 \u6e90\u7801\u7248\u672c\uff1a * Handler\uff1aSDK-35 * [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"","_lmt_disable":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[24,10],"tags":[31,20],"class_list":["post-120","post","type-post","status-publish","format-standard","hentry","category-source-android","category-source","tag-android","tag-20"],"modified_by":"admin","jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"http:\/\/www.devblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.devblog.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.devblog.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.devblog.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.devblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=120"}],"version-history":[{"count":6,"href":"http:\/\/www.devblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/120\/revisions"}],"predecessor-version":[{"id":224,"href":"http:\/\/www.devblog.cn\/index.php?rest_route=\/wp\/v2\/posts\/120\/revisions\/224"}],"wp:attachment":[{"href":"http:\/\/www.devblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.devblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=120"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.devblog.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}