Android tp的虚拟按键(virtual key)处理

Android tp的虚拟按键处理

现在在越来越多的Android的手机都是虚拟按键来操作，但是对于开发者来说可能会关心Android对虚拟按键如何处理的。对Linux熟悉的人可能会说，it's easy， 调用input_report_key（）。OK，你说的没有错误，但是在android中，google让你对策略和驱动有了更加深入的了解。

APP------->
          Framework------->
                         Kernel------->
                                      Hardware

上面就是整个Android的Virtual key的整个的框图。
由于是搞驱动的，所以这里先从驱动开始说起。
其实说起对virtual key的处理对于驱动来说没有任何的难处，实现了Touch panel驱动，你也就将virtual key的底层驱动实现了。这里你试验了吗？你可能会说，“不行，这里实现不了”。是的，这个时候还不行，还有关键的步骤得操作。

在这里，你需要如下代码加入才可以。

 

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staticunsigned inttpd_keycnt = 0;

staticint tpd_keys[TPD_VIRTUAL_KEY_MAX]={0};

staticint tpd_keys_dim[TPD_VIRTUAL_KEY_MAX][4];// = {0};

staticssize_t cust_virtual_keys_show(structkobject *kobj,

                   structkobj_attribute *attr, char*buf) {

    inti, j;

    for(i=0, j=0;i<tpd_keycnt;i++)

        j+=sprintf(buf,"%s%s:%d:%d:%d:%d:%d%s",buf,

           __stringify(EV_KEY),tpd_keys[i],

           tpd_keys_dim[i][0],tpd_keys_dim[i][1],

           tpd_keys_dim[i][2],tpd_keys_dim[i][3],

           (i==tpd_keycnt-1?"\n":":"));

    returnj;

}

  

  

staticstruct kobj_attribute cust_virtual_keys_attr = {

    .attr = {

        .name = "virtualkeys.cust-tpd",

        .mode = S_IRUGO,

    },

    .show = &cust_virtual_keys_show,

};

  

  

staticstruct attribute *cust_properties_attrs[] = {

    &cust_virtual_keys_attr.attr,

    NULL

};

  

  

staticstruct attribute_group cust_properties_attr_group = {

    .attrs = cust_properties_attrs,

};

  

  

structkobject *properties_kobj;

  

  

voidtpd_button_init(void) {

    intret = 0, i = 0, j=0;

  

  

    tpd->kpd=input_allocate_device();

    /* struct input_dev kpd initialization and registration */

    tpd->kpd->name = TPD_DEVICE "-kpd";

    set_bit(EV_KEY, tpd->kpd->evbit);

    for(i=0;i<tpd_keycnt;i++)

        __set_bit(tpd_keys[i], tpd->kpd->keybit);

    tpd->kpd->id.bustype = BUS_HOST;

    tpd->kpd->id.vendor  = 0x0001;

    tpd->kpd->id.product = 0x0001;

    tpd->kpd->id.version = 0x0100;

    if(input_register_device(tpd->kpd))

        TPD_DMESG("input_register_device failed.(kpd)\n");

    set_bit(EV_KEY, tpd->dev->evbit);

    for(i=0;i<tpd_keycnt;i++)

        __set_bit(tpd_keys[i], tpd->dev->keybit);

    properties_kobj = kobject_create_and_add("board_properties", NULL);

    if(properties_kobj)

        ret = sysfs_create_group(properties_kobj,&cust_properties_attr_group);

    if(!properties_kobj || ret)

    printk("failed to create board_properties\n");

}

  

  

voidtpd_button_setting(intkeycnt, void*keys, void*keys_dim)

{

        tpd_keycnt = keycnt;

        memcpy(tpd_keys, keys, keycnt*4);

        memcpy(tpd_keys_dim, keys_dim, keycnt*4*4);

}

有了上面的代码，我们的virtual key才可以使用，这里主要是需要注册/sys/board_properties/virtualkeys.cust-tpd。这个是framework需要的文件节点。他的出现可以使我们的虚拟按键畅通无阻了。
当然，在这里tpd_keys这个定义key的数组和定义区域的tpd_keys_dim要准确的填充才可以的。具体的填充的规则如下：
  0x01: A version code. Must always be 0x01. 
<Linux key code>: The Linux key code of the virtual key. 
<centerX>: The X pixel coordinate of the center of the virtual key. 
<centerY>: The Y pixel coordinate of the center of the virtual key. 
<width>: The width of the virtual key in pixels. 
<height>: The height of the virtual key in pixels. 
对比我的milestone来看看： 
0x01:158:32:906:63:57: 
0x01:139:162:906:89:57: 
0x01:102:292:906:89:57: 
0x01:217:439:906:63:57 

则可以看出定义了有back，menu，home，search，具体的区域也一清二楚了。

下面就是framework中的处理了，文件在framework/base/services/java/com/android/server/InputManager.java。
在其中通过调用getVirtualKeyDefinitions来获得定义的虚拟按键。
 

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publicVirtualKeyDefinition[] getVirtualKeyDefinitions(String deviceName) {

            ArrayList<VirtualKeyDefinition> keys = newArrayList<VirtualKeyDefinition>();

              

            try{

                FileInputStream fis = newFileInputStream(

                        "/sys/board_properties/virtualkeys."+ deviceName);

                InputStreamReader isr = newInputStreamReader(fis);

                BufferedReader br = newBufferedReader(isr, 2048);

                String str = br.readLine();

                if(str != null) {

                    String[] it = str.split(":");

                    if(DEBUG_VIRTUAL_KEYS) Slog.v(TAG, "***** VIRTUAL KEYS: " + it);

                    finalintN = it.length-6;

                    for(inti=0; i<=N; i+=6) {

                        if(!"0x01".equals(it[i])) {

                            Slog.w(TAG,"Unknown virtual key type at elem #"

                                    + i + ": " + it[i] + " for device " + deviceName);

                            continue;

                        }

                        try{

                            VirtualKeyDefinition key = newVirtualKeyDefinition();

                            key.scanCode = Integer.parseInt(it[i+1]);

                            key.centerX = Integer.parseInt(it[i+2]);

                            key.centerY = Integer.parseInt(it[i+3]);

                            key.width = Integer.parseInt(it[i+4]);

                            key.height = Integer.parseInt(it[i+5]);

                            if(DEBUG_VIRTUAL_KEYS) Slog.v(TAG, "Virtual key "

                                    + key.scanCode + ": center=" + key.centerX + ","

                                    + key.centerY + " size=" + key.width + "x"

                                    + key.height);

                            keys.add(key);

                        }catch(NumberFormatException e) {

                            Slog.w(TAG,"Bad number in virtual key definition at region "

                                    + i + " in: " + str + " for device " + deviceName, e);

                        }

                    }

                }

                br.close();

            }catch(FileNotFoundException e) {

                Slog.i(TAG,"No virtual keys found for device " + deviceName + ".");

            }catch(IOException e) {

                Slog.w(TAG,"Error reading virtual keys for device " + deviceName + ".", e);

            }

              

            returnkeys.toArray(newVirtualKeyDefinition[keys.size()]);

        }

其实找这个函数的调用的话，其实是发现通过JNI com_android_server_InputManager.cpp，InputReader.cpp来调用的。
最终通过notifyKey()来将key事件上报给app来处理。

在这其中还需要配置：
Key layout file: /system/usr/keylayout/touchyfeely.kl.

key 158 BACK
key 139 MENU
key 102 HOME
key 217 SEARCH

Key character map file: /system/usr/keychars/touchyfeely.kcm.

type SPECIAL_FUNCTION

其实这个例子给我的最大的感受是让我更加的了解了什么是策略，什么是机制，一定要区分清楚。读源码可以让自己的想法也会有些转变的。

 

Have Fun!

转自：http://www.2cto.com/kf/201307/230972.html