Android 再谈handler

今天在做http网络事件的响应网络接收处理一般不能放在主线程中使用，目前也只会使用AsyncTask进行处理！之前虽然写过handler处理的一些文章但是发现全不会了！无奈~

关于handler某位兄弟已经整理的很透彻了！现在引用下原话如下：

Handler监听者框架：子线程是事件源，主线程是监听者。
Handler作为子线程的监听器出现：主线程中生成Handler的子类，并重写handleMessage(Message msg) 方法，用来对子线程响应。子线程调用Hanlder的sendMessage(message)发送事件。

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.util.Log;
import android.widget.TextView;

public class MainActivity extends Activity {

    private final static String TAG = "ThreadTest";
    TextView myTv = null;
    int i = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myTv = (TextView) this.findViewById(R.id.tv1);
        // 执行该线程
        new Thread(runnable).start();
    }
    /**
     * 主线程监听者
     */
    Handler myHandler = new Handler() {
        public void handleMessage(android.os.Message msg) {
            Log.i(TAG, "begin--->handleMessage");
            if (msg.what == 0x000001) {
                myTv.setText(String.valueOf(i));
            }
            Log.i(TAG, "end--->handleMessage");
            super.handleMessage(msg);
        };
    };

    /**
     * 子线程事件源
     */
    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            while (!Thread.currentThread().isInterrupted()) {
                i++;
                Message msg = new Message();
                msg.what = 0x000001;
                Log.i(TAG, "begin--->sendMessage");
                myHandler.sendMessage(msg);
                Log.i(TAG, "end--->sendMessage");
                Log.i(TAG, "begin--->dosomething");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                Log.i(TAG, "end--->dosomething");
            }
        }
    };

}

打印下输出：发现它并不是等dosomething执行完毕之后再调用handlemessage事件，而是一旦调用sendmessage后就会执行handlemessage。

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q9qXx1qhutkFifMvHI9y5Z3XyJvxV9zneUQcF+F7UuIF0m3lOlxIq/FeeMg/b14rDvUnGA1M3fZIGuJV5KzxhaEoFlXU/1t/6EtCHwFp47jf6JfD6rUPdhWW/q/ojDpTnOZrLPj7u6nTGPyOp2423yrBA3ZPzalIh3diEdPdS6KCqIb+FIrdmcRqxIUkNljz5D6W9d3a/o7Kk4D0pbF+oMjxa7DsUZ33qS+FzMzRE48pHiyrOzbJGZd3ARDM9LUjaEZhMQqWaKHevDrtX9saza/C5qM+cSPWK02JKrUyaM/NCS1cfX+VuPu/YPeSbsN+LNg8IKx6L0frNpJvYXt4Loqn+Dfc3u4o1uvje+NTCG6ZINdO2Y52/9DWnh3pb6UmH1OZ//zjiE5ExUbvCcXyWdLa4S4oZSQ01bj4dl7P5Q4zwxcRqyozGpodHLkdMA8a1r+5U+OWQrCQjbA6VE0axQFf2tJwFzBI58orhig5d2uqBTuFH2J8ZEgS7pKKacTaVIVVPsWB/serJra4e2tjGjRYmNKeNGfsaVxy/xt4Iik8Tx88Sh2/1mA3lgYn9xSTD5W3y63yre6CYsPkOJY2Mo7se5rif5W39G2gn+VuUrs93UqoK/FV/O9aUkfyuNyUv+Vk2wkhf8LdwQ7NFneNLf6u9Xv7/VHorsEZ/+1jOgZxI08q/6W1cKHMe3CvsUZtMr/hY2RZdodhNqGzLaMrE5ZdLoWq2hcT57Xz7cStFBZy/5W830KAO4hQATD3wgWOZMj3uq179Q3weKo25GxeOr3yDxMobG8Ci2kIquJ53Q/SlpQ+tmu5XOzdmo7G8VZoODpv4UIBwHRDvreXooNmQ0fsCNJKy2juSM7d9o91WvXwIbgj2SWh9JHOdZf6u/X7FjFB+jgNahUqJEfKQSlEI6SOaIm9eCNsPpWPM8cYq/1XXVWJhNOOQmmmLH+gCfMAeMFiVKUwaMfOOU6Qk++nsQ8EIMjAo2BRv9RYk8oOqvwuA6cyuUcgpXfPCOUrvx1yoOuzlS5wUMjiFYF5CuZbX+S9JmsrkFooiEnzag7o/z2oGLvR/QbJJbz9qECrWJqjrCFd2bWm0lUkP2j2QzOdMf1EAB/9rkslVscTfdf9clVL6ZTH1haUYNFT2qtT7J3/Iy+Hom9StqSCt3H6VsXagzUV/c30wppAc7X/wcqWszTPBN68i7zWZTOW0vuCtirS5d9LB9IquTREKm2Lc++FmQ1HOeM/YZLbZkOGXQyItL1tPw904JIU/zR/7WnZC/BU9vP8XMkae/RQh5Ev/UztMlQi4gBFT4g7Tv5S0jT3+LEEIIIWQu9LcIIYQQQuZCf4sQQgghZC70twghhBBC5kJ/ixBCCCFkLvS3CCGEEELmQn+LEEIIIWQu9LcIIYQQQuZCf4sQQgghZC70twghhBBC5kJ/ixBCCCFkLm1/y78izb0n/Ercm7rjN2+7d3q327I5wVu7H3fV8TZv//Lw+H1JMLG3eHjHePweeKl80feh4gfqZvIS9WriRXSOYfpC+PA2UKhrUa3/mLR/GDSvX6/wbw9yPLu9vc3ul68ftk6+lqmGcWHlcVV9s97odAld1uv9iq+lN761rNfr/nFX52a2a+9emO189+3jruo+x7Le9A4FM3pdmgLb4rZ1r2+Y2F+8KbMH9r2/+HEcZTfNdvN1ei8BJl5F9xga7Qczevs61LWs1n9L2v8Bzw9LNOwX1PYdPO5K74e3LrOdHs/sftn6pdYHQEoh87jGMH4XhXzrC60uq6pd867VqvyqGz7/A3zS34rqDDtcWAj6pncpmF1ZRgSO9lch0T4dCmYRckoOU1kc9n3I36p1E7pWE/ytiPYYWty6fxxVXU/ehP6EtCHwpjcdmk7iE1EobjPL2ohbREEOl23X7pH0rMr7lGlIGzdkn03dc20+QbJhAa1DTpHy+OKyap1Haq1UatntsJzNwYaKHn2K3Mym9MuP4WZSLeStY6UEM9PKFheUQnooB/lxV7cfpdZi5EXFvYDVZrFkFVYHbOkJOduzftdq03YJXValN5WvOXVTFBLrE0HdF+0GoXchmsCX+FvR53xHGRTsd1HrAtJl4j1VSqz4W3HOOGhfLw77LhUHSN38TRboWuKl9IyhJRFY1vVUf+tPSBsCb+EJ1eifyOezCnUflvWm7o84XJrjbCb7/Lir2xnziKxuN94mzwpxQ8avYol4ZxfS0UOti6KC+BaO1JrNacSKJDVU9ugzlP7W1f3ytgFOjtLWhTrDo8WuQ3HGt55DHORC7zXFvUowp+M4JKtDc2RUzvas37W6P5ZVm99FbeZceEdMEdtndSKEU8uhhehqvs7fety1f8gzYb8Rbx5kgo1G6f1m00zsL24F0dXZgn3N7uKNbr43vjUwhumSDXTtmOdv/Q1p4d6W+lJhnTqfFM84hORMVG7wnF8lnS2uEuKGUkNNW4+HZez+UOM8MXEasqMxqaHRy5HTAPGta/uVPjlkKwkI2wOlRNGsUBX9raeQBjnS76kUrDi4/fUnxkSBLumApZwjvXI62rPerhK7ttZlaxszRZTYmAjOtfrsRcYv8beCypPE8fPEodv9ZgN5YGJ/cUkw+Vt4ttUs3ugmLD5DiWNjKO7Hua4n+Vt/RtoJ/lblK7Pd1KqCvxU9F4ZSkr+VRu8lf6smWMkL/hZuCPboMzzpb/X3q9/fag9FFgygv/UEwiCP+jEvk4SfgdUJc+QVfwv33SWa3YTahkyxTGxOhDS6VmtoJp+9Lx9upeig3Zf8rWZ6lAHcQoCJBz4QLHOmxz3V61+o7wPFUTej4vHVb5B4GUNjeBRbSEXXk07o/pS0oXWz3Urn5mxU9rcKs8EruD8vCAcH0c56nh6KDRmNH4UjCautIzlj+zfafdXrl8CGYI+k1kcSx3nW3+rvV+wYxQcuoHWolCgRH74EpZAOpHmX+zFVxb1E1wViYY6Mytme9fC5ccAUUaI0EeLT27L42/no70HACzEwftgUbPQXJfLQK4zc5nHRxFmGOYUrPnhHqd0NbBWH3Ryp8wIGxxBE8pCuZbX+S9JmsrmlpIiZnzag7o/zgoKL0h/QbJJbz9qECrWJqjoO/6fdN7XaSqSG7B/JZnKmP6iBjgZqk8tWscXddP9dl1D5ZjL1hUUcNVT0qNb6JH/Ly+DrmdSvqCGt3M2VsnWhzkR9cX8zpZBeOuZdeOYpFPcS1pbSerDVIVsakbNv1nvbTuo5zxn7TBHbJ5wIYcHcdFjPhYXoDfD3TgkhT4NPwwkh5Iv4jtNw+luEkCfxkS2eLhFCvo4QyvqKH/ilv0UIIYQQMhf6W4QQQgghc6G/RQghhBAyF/pbhBBCCCFzob9FCCGEEDIX+luEEEIIIXOhv0UIIYQQMhf6W4QQQgghc6G/RQghhBAyF/pbhBBCCCFzob9FCCGEEDKXtr/lX5Hm3ih+Je6d3vE7ut3bv9tt2Zzg/d6Pu+p477d/zXj8ZiWY2Fs8vI3856buj0b5ou9DxQ/UzeR169XEi+gcw/TV8eG9oVDXolrfJW1dsJ6c/zpoXr9e4QyTeB/x7PZWNLtfvn7YOnkDy3rF4vC7qE/b/5fMwZoYXzBKdXrjW8t6fTced3Vuvbv27oXZznffPu6q7nMs603vUDCj16UpsC1uW/fzASb2F2/K7IF97y9+HEfZTbPdfJ3ep4GJV9E9hkb7wYze0w51Lav1bdLWBOvJSSzPKzEykgtq+w4ed6X3w88Fs50ez+x+2fql1gdASiEdRKvfN/O7qJYX/oE5+P9aCj7pb0V1BosMC0Hf9C4FsyvLiMBwPiSJ9unw3G7lnNKmWxaHfR/as2vdhK7VBH8roj2GFrfuH0dV15NnVEPalhE+b65jQrpQhN50aCWJT0SBw80sayNuEQU5XLZdu0DUWZV3H9OQNm7IPru7aFY+QTIlgtYhp0h5NHRZtc4jtVYqtex2WM7mYENFjz5FbntT+uXHcDOpFvLWsVKCmWlliwtKIR0YvS5+nP0cwSPvxlndF+3GWTgJUWq9OlRp9Z4pF9pSvhBlic5sQE5xyZJXp56lYGSU0CC/hy/xt46GIvsF+13UuoB0mdgDkBIr/lacMw7a14vDvkvFAVI3f5MFupZ4KT1jaEkElnU91d9qS1s1wv6crxDCaeG50+ifyL2zCnUflvWm7o84XJrjbCb7/Lir2xnziKxuN94mzwpxQyZasCLxzi6kukati6KCh1ocqTWbG3wrktRQ2aPPUPpbV/crOlUpDl/S1oU6w1PErkNxxreexOjkuUUtv8LIR4orTyGzJXHewUUwvEOyJbQQYbPpXrIk8x5ZCo6eUaoO8my+zt963LV/yDNhvxFvHhTjOxal95tNM7G/uBVEV/0b7Gt2F290873xrYExTCcP0LVjnr/VI21FsP6cLwH3ttSXOt0+l3NxcQjJmajc4Dm/SlRTXCXEDaWGmrYeK3Hs/lDjECFxGrKjMamh0cuR0wDxrWv7lT5OZCsJCNsDpURxheTRgv7WM4A5Akc+f5Br+FtRNDS4a4U2+xNjXKAL2xJciA5kNt1LlmiKI0tBzyjVB3k2X+JvhVFLEsfPE4du95sN5IGJ/cUlweRv8el+q3ijm7D4DCWOjaG4H+e6nuRvdUorCdaf81Um+FuVr8x2U6sK/lZ87dSXkvyt9BhL8rdqgpW84G/hhmCPPsOT/lZ/v/r9rfZQtCINpAP0TIJG/lV/60qBgzc/4G95vPD9S5ZkivS3riLEBn4XHe7Lv+RvNdOjDODgFiYe+ECwzJnGTqvXv1DfB4qjbkbF44vqIPEyhsbwKLaQiq4n3ZfvlBYK1p/zImmTqwmlc3MOkexvFWaDg6Y+5B5i79Ead8b8xYaMjsJFmX7zm0NCyBaYd7B/o91XvX4JbAj2SGp9JHGcZ/2t/n7FW1R8IAhah0qJEvEpT1AK6SCZI25eC9qM/hCndZ44xd/KjRzbElqIsNn0L1nC+jCyFBw9o1Qd5Nl89Pcg4N0XGMpuCjb6ixJ5QNWfK+M6gRXCnMJtHryj1O4btorDbo7UeQGDYwjWBaRrWa1vlLYUrD/nDIHdklccHp02oO6P8y7Crm/pnfdEquT+qTahQm2iqo5w+fSmVluJ1JD9I9lMzvTnP/DtV3ly2Sq2uJvuv+sSKt9MppTgRaGGih7VWp/kb3kZfD2T+hU1pJW7pFK2LtSZqC/ub6YU0oOdL36O1LUZJvimdeRnZLOpnLYX3BWxVgfD/4UtodN5bDYDS5awPnQtBSOjhAb5TfD3TgkhT/NH/tadkL8FT2/fwNsHmf4WIeRJ/FM7T5cIuYAQ4+EP0k7jc4NMf4sQQgghZC70twghhBBC5kJ/ixBCCCFkLvS3CCGEEELmQn+LEEIIIWQu9LcIIYQQQuZCf4sQQgghZC70twghhBBC5kJ/ixBCCCFkLvS3CCGEEELmQn+LEEIIIWQubX/LvyLNvZT7Styrv3X00kj3Ku92WzanLl84+bgrmI6KZy9Rgom9xdFb0+XyoO/HEQa8/Wqnspuuzrxs34A8QecYpi9vD68IhboW1fouaeuC9eT815Fs+7UKZ5jE+4gXB29Fs/vl64etk6/lbQb/JTOrJsbvor5AwkvojW8t6/UdftzVufXu2nsnZjvfffu4q7rLsqw3vUPBjF6XpsC2uG3db5Ywsb94U2YP7LuttrOGsptmu/k6b8lrz7sG5Am6x9BoP5jRK9mhrmW1vk3ammA9OYnleSVGRnJBbd/B4670fvi5YLbT45ndL1u/1PoASClkHtcYxu+iWr71B2bW/3GC9/BJfyuqM+zHYSHom96lYHZlGRE48gaERPt0eG63ck5p0y2Lw75nvledWjdTf2t8QJ6gPYaxMOfXsq4/K23LCJ831zEhXShCbzq0ksQnosDhZpa1EbeIghwu265dIOqsyruPaUgbN7Sst9u6uGhWPkEyJYLWIadIeTR0WbXOw7dWKrXsdljO5mBDRY8+RW57U/rlx3AzqVCzNK4AAAQRSURBVBby1rFSgplpZYsLSiE9lIP8uKvbj1LlUYaouBew2sxUBhvKl5cs0RkDyCkuRPKa0zPBQaS8OXTqvuhvNdEv8beOhsr7Bftd1LqAdJnYA5ASK/5WnDMO2teLw74/7lpvCm5dOVI3f5MFupbzUnrG0JKIIev6w9JWjbA/5yuEcFp4QjX6J3LvrJbdhzMyWnHZnSVknx93dTtjHpHV7cbv8WeFuCETLW2ReGcXgB3mnyVRweMvDt+azQ2+FUlqqOzRZyj9rav7FZ2/FMc0aetCneEpYtehOONbzyEOcqH3muJeJZiT2BBaXrAxdC9EktGOTPCj2A7qQ2cfAp8dp7l8nb/1uGv/kGfCfiPePCg0MRal95tNM7G/uBVEV2cL7Htq+rXijW5G9vqGY4uBMUynGdC147PSVgTrz/kScG9LfanT7XM5FxeHkJyJyg2e86s0JprfRMQNpYaaH45nT6Xd94caxw2J05AdjUkNDd2tnAmIb13br/RxIltJQNgeKCWKQCSPFvS3xpEGOdLvqRSsOLj99SfGuEAXbgguLwcyhu6FSDSwkQl+yLs8Hrrm49zn+BJ/K4xvkjh+njh0u99sIA9M7C8uCSZ/Gx9O3aJ7bLUNqdlNX//UP3c4RsdQ3I9zXU/ytzqllQTrz/kqE/ytyldmu6lVBX8rvqDqS0n+VnqMJflbQ2flr/hbuCHYo8/wpL/V369+f6s9FK2YBGkjDHKvv3UZISg15m95vDH0L0SSgdHfqjPnvny4laKDn/GSv9VMjzKAI16YeOADwTJnGmWtXv+CfU+jzXlsAJ4wJjYaP54WBjfpBnr/GB7FFlLR9WelhYL157xI2uQSQ+ncnEMk+1uF2eAV3AfnQ5Q+Wg3DH3CI8S3xISG/OSTsH8C8w0Qw2n3V65fAhmCPpNZHEsd51t/q71e8mcUHgqB1qJQoEZ8HBaWQDqR5lzsNVcW9RG66uCG0vGBj6F+IhFk/MsGPDn8rP6j9u/7WxAAJvPsCQ9lNwUZ/USIPvcLIrezxSDmF2zx4R5FzwsOdYjSKbop3ieb8ZsHgGJazCOpaVusbpS0F6885Q2BnDMXh0alZdX+ctxZ2fUvvvCdSJTdVtQkVahNVdYRrqje12kqkhuyfvmZypj//ge/JNh4nggCxPOsSKt9MppTgRaGGih7VWp/kb3kZfD2T+hU1pJW7zlK2LtSZqC/ub6YU0kvHvAvPPIXiXsLaEgzqFw2hM3dsDAMLkTDruyY4WkmkoYu2To3+HOor4O+dEkKeBv6lJyGEfIgvPvimv0UIeRIf2eLpEiHkk4RA2vf+li/9LUIIIYSQudDfIoQQQgiZC/0tQgghhJC50N8ihBBCCJkL/S1CCCGEkLnQ3yKEEEIImct/6gt5p4e0iZIAAAAASUVORK5CYII=" alt="" />

Handler钩子方式：在主线程中生成一个Hanlder，用Handler的Post(Runnable)方法可以将Runnable钩到主线程中运行。

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.widget.TextView;

public class MainActivity extends Activity {

    private final static String TAG = "ThreadTest";
    TextView myTv = null;
    //handler在主线程中创建，调用post的时候钩子会把它钩回主线程
    Handler  myHandler = new Handler();
    int i = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myTv = (TextView) this.findViewById(R.id.tv1);
        new Thread(runnable1).start();
    }

    /**
     * 子线程
     */
    Runnable runnable1 = new Runnable() {
        @Override
        public void run() {
            while (true) {
                i++;
                myHandler.post(runnable2);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    };

    /**
     * 使用钩子将该子线程钩到主线程中
     */
    Runnable runnable2 = new Runnable() {
        @Override
        public void run() {
            myTv.setText(String.valueOf(i));
        }
    };

}

对于我们有了这样子的一个handler，如果需要进行一个非常耗时的网络请求，也不必担心迟迟无法显示activity。因为下载的任务交给了我们的子线程。当完成任务的时候我们可以调用sendMessage方法，通知主线程更新UI。bingo！真是太棒了！