Android 底层知识拾零，app架构升级

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2.Android手机做热点时,如何获取连过来设备的具体信息?

1、连接过来的设备的信息存放在/data/misc/dhcp/dnsmasq.leases中

2、它的格式是:

/系统id,不需取值/client mac地址/client ip地址/ client device name/加权后mac地址,也不需取值

1357041758 88:00:12:34:56:78 192.168.43.133 android-184cc6c105d7a3b 01:88:00:12:34:56:78

3、参考WifiServie.java的getClientIp()方法,可以自定义这个方法取得device name,具体如下:

public String getClientDeviceName(String deviceAddress) {//传mac地址进来

enforceAccessPermission();

if (TextUtils.isEmpty(deviceAddress)) {

return null;

}

//读取对应的文件信息

for (String s : readClientList("/data/misc/dhcp/dnsmasq.leases")) {

if (s.indexOf(deviceAddress) != -1) {

String[] fields = s.split(" ");

//校验数据是否破损

if (fields.length > 4) {

//返回第4个栏位

return fields[3];

}

}

}

return null;

}

3.在Fastboot里添加命令

fastboot 是android 默认的一种debug 方法,它的好处是在进入linux kernel 之前

即可操作。

默认fastboot 支持的命令:

usage: fastboot [ ]

commands:

update reflash device from

update.zip

flashall flash boot

• recovery + system

flash [ ] write a file to a flash

partition

erase erase a flash

partition

format format a flash

partition

getvar display a

bootloader variable

boot [ ] download and boot kernel

flash:raw boot [ ] create bootimage and flash it

devices list all

connected devices

continue continue

with autoboot

reboot reboot

device normally

reboot-bootloader reboot device

into bootloader

help show this

help message

options:

-w erase userdata and cache (and

format if supported by partition type)

-u do not first erase partition

before formatting

-s specify device serial number or path to

device port

-l with “devices”, lists device

paths

-p specify product name

-c override kernel commandline

-i specify a custom USB vendor id

-b <base_addr> specify a custom kernel base

address

-n specify the nand page size.

default: 2048

-S [K|M|G] automatically sparse files

greater than size. 0 to disable

fastboot 提供了扩展的命令符号

fastboot oem command args

下面以fastboot oem hello test 来说明如何扩展

(1).在bootable/bootloader/lk/app/mt_boot/fastboot.c

的fastboot_init 函数中添加一个新的register

//第一个参数是命令的名称

//第二个参数是命令的执行函数

//第三个参数是在security IC 中是否还提供此命令

fastboot_register(“oem hello”, cmd_oem_hello, FALSE);

(2). 实现cmd_oem_hello 函数

void cmd_oem_hello(const char *arg, void *data, unsigned size) {

//注意args 是以command 结束开始,即" args"

if(!strncmp(arg, " OK", strlen(" OK"))){

fastboot_okey(“OK”);

}else{

fastboot_fail(“Not OK”);

}

}

(3). 与PC 端交互

您可以使用下面已经定义好的三个函数与PC 端交互

fastboot_okey(const char* result);

fastboot_fail(const char* reason);

fastboot_info(const char* reason);

注意这三个打印字符串的长度都不能超过64-1-4 = 59 个字

4.在任意界面按某个实体键进入某个Activity

有些手机会有附加的功能键，比如拍照实体键，甚至有两端式的，轻按聚焦，深按拍照。那么类似功能是如何在Android手机上实现的呢？

可以修改源码下

frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java文件中的如下方法:

public long interceptKeyBeforeDispatching(WindowState win, KeyEvent event,int policyFlags)

找到如下代码段:

else if (keyCode == KeyEvent.KEYCODE_APP_SWITCH) {

if (down && repeatCount == 0 && !keyguardOn) {

showOrHideRecentAppsDialog(RECENT_APPS_BEHAVIOR_SHOW_OR_DISMISS);

}

return -1;

}

在这个else if后面增加相应代码:

else if (keyCode == KeyEvent.KEYCODE_APP_SWITCH) {

if (down && repeatCount == 0 && !keyguardOn) {

showOrHideRecentAppsDialog(RECENT_APPS_BEHAVIOR_SHOW_OR_DISMISS);

}

return -1;

} //add begin

else if (keyCode == KeyEvent.KEYCODE_XXX) {

if (down && repeatCount == 0 && !keyguardOn) {

mContext.startActivity(new Intent(“intent.xxx”)

.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK));

}

return -1;