Android 中input学习--取得input事件

有的时候我们并不希望起个View，从画面上得到各种输入事件。

怎么从底层得到各种input事件呢？

首先android下有个工具getevent，输出结果如下：

$ adb shell geteventadd device 1: /dev/input/event7  name:     "proximity"add device 2: /dev/input/event6  name:     "lightsensor-level"add device 3: /dev/input/event5  name:     "compass"add device 4: /dev/input/event4  name:     "saga-keypad"add device 5: /dev/input/event3  name:     "atmel-touchscreen"add device 6: /dev/input/event2  name:     "projector-Keypad"add device 7: /dev/input/event1  name:     "projector_input"add device 8: /dev/input/event0  name:     "h2w headset"/dev/input/event4: 0001 0074 00000001/dev/input/event6: 0003 0028 ffffffff/dev/input/event6: 0000 0000 00000000/dev/input/event6: 0003 0028 00000005/dev/input/event6: 0000 0000 00000000/dev/input/event3: 0003 0030 00000000/dev/input/event3: 0000 0000 00000000/dev/input/event3: 0003 0030 00000000/dev/input/event3: 0000 0000 00000000/dev/input/event4: 0001 0074 00000000

/dev/input/event？都是一些输入设备，

比如event3是触摸屏的，event5是罗盘的，event4是物理键盘的，等等。

既然getevent能取到这些信息，那我们能不能自己写程序获得这些事件呢，

当然可以，以event3（触摸屏事件）为例：

#include <fcntl.h>#include <linux/input.h>#include <errno.h>#include <poll.h>static char TOUCH_DEVICE[256] = "/dev/input/event3";int touchfd = -1;struct pollfd fds[1];static void init_touch(){        if((touchfd = open(TOUCH_DEVICE, O_RDWR)) == -1)        {                printf("cannot open touch device %s\n", TOUCH_DEVICE);//                exit(-1);        }fds[0].fd = touchfd;fds[0].events = POLLIN;}int getevent(){    struct input_event event;int res = 0;res = poll(fds, 1, -1);while(true) {if(fds[0].revents) {if(fds[0].revents & POLLIN) {res = read(touchfd, &event, sizeof(event));if(res < (int)sizeof(event)) {    fprintf(stderr, "could not get event\n");    return 1;}printf("getevent: %04x %04x %08x\n", event.type, event.code, event.value);}}}return 0;}

能取到了，怎么用就不说了

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