2022年4月

参考：

Java 11 – String.repeat()介绍
https://blog.csdn.net/w116858389/article/details/116644332

New String APIs/Methods in Java 11
https://www.javaguides.net/2018/08/java-string-class-api-guide.html

java中将字符(Char)转换为字符串的四种方式
http://www.jquerycn.cn/a_17663

Java字符串篇-2-String类几个常见构造方法
https://blog.csdn.net/u011541946/article/details/79854672

android开发中byte[]转换成String
https://blog.csdn.net/u010477502/article/details/51854261

[转] java byte[] hex打印
https://www.cnblogs.com/tinyos/p/7208709.html

JAVA byte数组转化为16进制字符串输出
https://blog.csdn.net/x_iya/article/details/54136799

Android byte字节数组转换十六进制字符串（物联网开发总结）
https://blog.csdn.net/qq_31939617/article/details/82413926

android byte字节数组转换十六进制字符串
https://blog.csdn.net/zhao_liwei/article/details/51985391

Android MD5后 bye数组转化为Hex字符串的坑（记一次为女神排忧解难的经历）
https://cloud.tencent.com/developer/article/1132772

Andrid打印数组的方法
https://blog.csdn.net/Sunxiaolin2016/article/details/90080355

参考:

禁用Android底部虚拟按键
https://blog.csdn.net/cao861544325/article/details/81748095

android 系统隐藏和显示虚拟按键的几种方法
https://blog.csdn.net/xct841990555/article/details/102810360

Android 隐藏底部虚拟键的两种方法
https://cloud.tencent.com/developer/article/1741856

android:backgroundDimEnabled的作用
https://blog.csdn.net/chuyouyinghe/article/details/73468648

修改 app 为系统应用

在 AndroidManifest.xml 中如下增加 android:sharedUserId="android.uid.system

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
            package="com.google.example"
            android:sharedUserId="android.uid.system">

问题：

注意编译后，会报错提示不能安装，这个没关系。系统 app 是需要后来放到 aosp 中去的。 具体方法，见读取 imei 的文章。

参考:

Android普通应用升级为系统应用，获取系统权限
https://blog.csdn.net/weixin_42484608/article/details/83028528

android 系统级别应用
https://blog.csdn.net/jinmv/article/details/44646277

制作Android系统App
https://blog.csdn.net/zxy1198186906/article/details/88394141?utm_medium=distribute.pc_relevant.none-task-blog-2~default~baidujs_baidulandingword~default-0.pc_relevant_default&spm=1001.2101.3001.4242.1&utm_relevant_index=2

修改安卓系统应用,将自己的app变成系统应用
https://blog.csdn.net/u012930316/article/details/100740399

秒懂Android开发之权限总结
https://zhuanlan.zhihu.com/p/158899172

Android app获取系统权限
https://blog.csdn.net/VSRfind/article/details/79648281

参考:

udelay、mdelay、ndelay、msleep使用比较说明
https://www.cnblogs.com/Ph-one/p/4678361.html

arm体系下的cpu_relax()函数疑惑
http://www.wowotech.net/forum/viewtopic.php?id=21#:~:text=cpu_relax%E5%BF%85%E9%A1%BB%E5%85%B7%E5%A4%87%E4%B8%A4%E4%B8%AA%E5%8A%9F%E8%83%BD%EF%BC%9A%201%E3%80%81%E7%A1%AE%E4%BF%9D%E5%AF%B9flag%E7%9A%84%E8%AE%BF%E9%97%AE%E6%AF%8F%E6%AC%A1%E9%83%BD%E4%BB%8Ememory%E4%B8%AD%E5%8A%A0%E8%BD%BD%EF%BC%8C%E4%B9%9F%E5%B0%B1%E6%98%AFbarrier,%28%29%E5%87%BD%E6%95%B0%E7%9A%84%E4%BD%9C%E7%94%A8%202%E3%80%81%E9%80%9A%E7%9F%A5%E5%BA%95%E5%B1%82CPU%EF%BC%8C%E7%9B%AE%E5%89%8D%E4%BB%A3%E7%A0%81%E6%B2%A1%E6%9C%89%E5%9C%A8%E5%81%9A%E4%BB%80%E4%B9%88%E5%AE%9E%E9%99%85%E6%9C%89%E6%84%8F%E4%B9%89%E7%9A%84%E4%BA%8B%E6%83%85%EF%BC%8C%E5%A6%82%E6%9E%9C%E5%8F%AF%E4%BB%A5%E7%9A%84%E8%AF%9D%EF%BC%8C%E5%88%AB%E8%AE%A9cpu%E5%81%9A%E5%A4%AA%E5%A4%9A%E4%BA%8B%E6%83%85%EF%BC%8C%E7%B3%BB%E7%BB%9F%E7%9A%84%E8%B5%84%E6%BA%90%E5%B0%BD%E9%87%8F%E8%AE%A9%E7%BB%99%E5%85%B6%E4%BB%96%E7%9A%84cpu%E3%80%82

问题：

硬件电路里面按键时高电平有效，从 getevent -l 这边看，kernel 上报时没有问题的，只是up 和 down 反过来而已，有一下，就发一条信息。但是在 app 里面就不一样了，每当 app 的界面出现前后台切换的时候，会对所有的按键进行刷新，导致出现一直刷新按键事件的情况。

解决方法：

直接修改按键本身比较困难，最简单方法是新建一个驱动文件，专门针对这个高电平有效按键即可。

//#define DEBUG

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/input.h>
#include <linux/input/mt.h>

#include <linux/platform_device.h>

#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/of_device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/pinctrl/consumer.h>
#include <linux/regulator/consumer.h>
#include <linux/power_supply.h>

#include <linux/uaccess.h>

#include <linux/kdev_t.h>
#include <linux/device.h>
#include <linux/wait.h>

static struct class *gpio_reverse_key_class;

 struct gpio_reverse_key_detect {
        struct device *dev;
        struct input_dev *p_inputdev;

        unsigned int gpio_reverse_key_gpio;
        unsigned int gpio_reverse_key_irq_num;

        struct workqueue_struct *gpio_reverse_key_detect_wq;
        struct delayed_work gpio_work;

        atomic_t state;
        unsigned int code;

};

static int reverse_key_count = 0;

static void gpio_reverse_key_detect_work_func(struct work_struct *work){
        struct gpio_reverse_key_detect *dev_struct;
        int old_state, new_state;
        printk("gpio_reverse_key_detect in work func\n");
        dev_struct = container_of(work, struct gpio_reverse_key_detect, gpio_work.work);

        reverse_key_count = 0;
        old_state = atomic_read(&dev_struct->state);
        new_state = gpio_get_value(dev_struct->gpio_reverse_key_gpio);
        if (new_state < 0) {
                dev_err(dev_struct->dev,
                        "failed to get qrcode-gpio state: %d\n", new_state);
                return;
        }

        if(new_state != old_state){
                dev_err(dev_struct->dev, "qrcode_detect update state %d", new_state);
                atomic_set(&dev_struct->state, new_state);
                input_report_key(dev_struct->p_inputdev, dev_struct->code, new_state);
                input_sync(dev_struct->p_inputdev);
        }

        printk("gpio_reverse_key_detect repot the key %d, value %d\n", dev_struct->code, new_state);
        enable_irq(dev_struct->gpio_reverse_key_irq_num);
        printk("gpio_reverse_key_detect enable irq");
}

static irqreturn_t gpio_reverse_key_detect_func(int irq, void *dev_id){
        struct gpio_reverse_key_detect * dev_struct = dev_id;

        printk("gpio_reverse_key_detect in irq func\n");
        disable_irq_nosync(dev_struct->gpio_reverse_key_irq_num);
        //printk("gpio_reverse_key_detect disable irq\n");

        if(!reverse_key_count){
                        schedule_delayed_work(&dev_struct->gpio_work,msecs_to_jiffies(20));
                        reverse_key_count = 1;
        }else{
                cancel_delayed_work(&dev_struct->gpio_work);
                schedule_delayed_work(&dev_struct->gpio_work,msecs_to_jiffies(20));
        //queue_work(dev_struct->gpio_reverse_key_detect_wq, &dev_struct->work);
        //printk("gpio_reverse_key_detect queue work ok\n");
        }

        return IRQ_HANDLED;

}

static int gpio_reverse_key_detect_input_set(struct gpio_reverse_key_detect *dev_struct){
        int ret;

        printk("gpio_reverse_key_detect input set begin\n");
        dev_struct->p_inputdev = input_allocate_device();
        if (dev_struct->p_inputdev == NULL) {
                printk("Failed to allocate input device.\n");
                return -1;
        }
        __set_bit(EV_KEY, dev_struct->p_inputdev->evbit);
        dev_struct->p_inputdev->name = "gpio_reverse_key_detect_input";
        //__set_bit(KEY_VOLUMEDOWN, dev_struct->p_inputdev->keybit);
        __set_bit(dev_struct->code, dev_struct->p_inputdev->keybit);
        printk("gpio_reverse_key_detect input set bit %d\n", dev_struct->code);
        input_set_drvdata(dev_struct->p_inputdev, dev_struct);

        ret = input_register_device(dev_struct->p_inputdev);
        if (ret) {
                printk( "Register %s input device failed.\n",dev_struct->p_inputdev->name);
        //      goto exit_free_inputdev;
        }
        printk("gpio_reverse_key_detect input set successd \n");
        return 0;
}

static int gpio_reverse_key_detect_probe(struct platform_device *pdev){
        struct gpio_reverse_key_detect *dev_struct;
        int ret;
        int state;
        printk("gpio_reverse_key_detect probe begin\n");
        dev_struct = devm_kzalloc(&pdev->dev,sizeof(struct gpio_reverse_key_detect) , GFP_KERNEL);
        dev_struct->dev = &pdev->dev;

        dev_struct->gpio_reverse_key_gpio = of_get_named_gpio(dev_struct->dev->of_node, "gpio_reverse_key_gpio", 0);

        gpio_request(dev_struct->gpio_reverse_key_gpio, "gpio_reverse_key_gpio");

        dev_struct->gpio_reverse_key_irq_num = gpio_to_irq(dev_struct->gpio_reverse_key_gpio);

        gpio_direction_input(dev_struct->gpio_reverse_key_gpio);

        if(of_property_read_u32(dev_struct->dev->of_node, "linux,code", &dev_struct->code)) {
                dev_err(dev_struct->dev, "fail to get linux code\n");
                return (-EINVAL);
        }
        printk("gpio_reverse_key_detect probe get key code %d\n", dev_struct->code);

        gpio_reverse_key_detect_input_set(dev_struct);

        dev_struct->gpio_reverse_key_detect_wq = create_singlethread_workqueue("gpio_reverse_key_detect_wq");

        INIT_DELAYED_WORK(&dev_struct->gpio_work, gpio_reverse_key_detect_work_func);

        state = gpio_get_value(dev_struct->gpio_reverse_key_gpio);
        if(state < 0) {
                dev_err(dev_struct->dev, "fail to init base_detect state %d\n", state);
                return (-EINVAL);
        }
        atomic_set(&dev_struct->state, state);

        ret = devm_request_threaded_irq(&pdev->dev, dev_struct->gpio_reverse_key_irq_num, (irq_handler_t)gpio_reverse_key_detect_func, NULL, IRQF_TRIGGER_FALLING |IRQF_TRIGGER_RISING | IRQF_ONESHOT, "gpio_reverse_key_detect", dev_struct);
        if (ret) {
                printk("quectel sc20 %s  create gpio_reverse_key_class err\n", __func__);
                        return ret;
        }

        printk("gpio_reverse_key_detect probe end\n");
        return 0;
}

static struct of_device_id of_device_sc20_gpio_match_table[] =
{
        {.compatible = "quectel,gpio_reverse_key_detect"},
        {},
};

int gpio_reverse_key_detect_remove(struct platform_device *pdev)
{
        int ret = 0;
//      struct  = NULL;
//      sc20_gpio_dev = (struct sc20_gpio_device *)dev_get_drvdata(&pdev->dev);
//      if(sc20_gpio_dev)
//              kfree(sc20_gpio_dev);
        printk("quectel sc20 %s enter\n", __func__);

        return ret;
}

static struct platform_driver gpio_reverse_key_platform_driver =
{
        .probe = gpio_reverse_key_detect_probe,
        .remove = gpio_reverse_key_detect_remove,
        .driver =
                {
                        .name = "GPIO_REVERSE_KEY",
                        .owner = THIS_MODULE,
                        .of_match_table = of_device_sc20_gpio_match_table,
                }
};

static int __init gpio_reverse_key_detect_init(void)
{
        int ret = 0;
        printk("quectel sc20 %s enter\n", __func__);
        gpio_reverse_key_class = class_create(THIS_MODULE, "gpio_reverse_key_detect");
        if (IS_ERR(gpio_reverse_key_class))
                {
                printk("quectel sc20 %s  create gpio_reverse_key_class err\n", __func__);
                return PTR_ERR(gpio_reverse_key_class);
                }

//      sc20_gpio_class->dev_attrs = sc20_gpio_class_attrs;

        printk("quectel sc20 %s  create gpio_reverse_key_class success\n", __func__);
        ret = platform_driver_register(&gpio_reverse_key_platform_driver);

        return ret;
}

module_init(gpio_reverse_key_detect_init);

static void __exit gpio_reverse_key_detect_exit(void)
{
        printk("quectel sc20 %s enter\n", __func__);
}
module_exit(gpio_reverse_key_detect_exit);

mODULE_DESCRIPTION("QUCTEL sc20 GPIOS_REVERSE_KEY");
mODULE_LICENSE("GPL v2");

参考：

按键响应onKeyDown，onKeyLongPress，onKeyUp
https://www.jianshu.com/p/83a1dd9db896
onKeyPress Vs. onKeyUp and onKeyDown
https://stackoverflow.com/questions/3396754/onkeypress-vs-onkeyup-and-onkeydown#:~:text=The%20onKeyDown%20event%20is%20triggered%20when%20the%20user,%26%20releases%20a%20key%20%28onKeyDown%20followed%20by%20onKeyUp%29.
onkeyup、onkeydown和onkeypress的区别
https://blog.csdn.net/czh500/article/details/80330207
安卓onkeyup onkeydown事件小记
https://blog.csdn.net/sjpz0124/article/details/50619524#:~:text=android%20Activity%E7%B1%BB%20onKeyUp%20%28%29%2C%20onKeyDown,%E7%95%A5%E8%AF%BB%20Activity.%20onKeyDown%20%28%29%3B%20%E5%BD%93%E6%9F%90%E4%B8%AA%E9%94%AE%E8%A2%AB%E6%8C%89%E4%B8%8B%E6%97%B6%E4%BC%9A%E8%A7%A6%E5%8F%91%EF%BC%8C%E4%BD%86%E4%B8%8D%E4%BC%9A%E8%A2%AB%E4%BB%BB%E4%BD%95%E7%9A%84%E8%AF%A5Activity%E5%86%85%E7%9A%84%E4%BB%BB%E4%BD%95view%E5%A4%84%E7%90%86%E3%80%82

问题

Android Studio一直 Download fastutil-x.x.x.jar， 应该是被墙了。

解决方法

在项目目录下面的 build.gradle 里面添加 aliyun：

buildscript {
    repositories {
        maven {
            url 'https://maven.aliyun.com/repository/google';
        }
        maven {
            url 'https://maven.aliyun.com/repository/public';
        }
        maven {
            url 'https://maven.aliyun.com/repository/jcenter';
        }
        google()
        mavenCentral()
    }
    dependencies {
        ...
    }
}

参考:

Android Studio一直Download fastutil-x.x.x.jar
https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/118637583?spm=1001.2101.3001.6661.1&utm_medium=distribute.pc_relevant_t0.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_default&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_default&utm_relevant_index=1
Download fastutil-8.4.0-sources jar一直加载问题
https://blog.csdn.net/qq_48092631/article/details/119818131

java 的 ymodem 可以使用 github 上面的 YModemForAndroid，链接是 https://github.com/LeonXtp/YModemForAndroid

问题：

直接使用 YModemForAndroid 有以下几个问题

  • 在最后不足 1024 的数据时，应该按照 128 来发送，而不是 1024 来发送。 补足 1024 的是 xmodem-1k 的协议，ymodem 是按照 128 来发。
  • 正常 ymodem 不需要检查 md5，这边的实现需要调整一下。

参考：

当Android BLE遇上YModem
https://www.jianshu.com/p/d37eb7fa1d6e

【安卓相关】蓝牙基于Ymodem协议发送bin文件，对硬件设备进行升级。
https://www.jianshu.com/p/85784aa3143b

YMODEM协议简介
https://zhuanlan.zhihu.com/p/81133050

stm32 Bootloader设计(YModem协议)
https://www.amobbs.com/thread-5559677-1-1.html

Ymodem协议详解
https://blog.csdn.net/lcmsir/article/details/80550821/

Ymodem 协议详解
https://blog.csdn.net/huangdenan/article/details/103611081

BGAUpdate-Android
https://github.com/bingoogolapple/BGAUpdate-Android

YModemForAndroid
https://github.com/LeonXtp/YModemForAndroid

YModemlib_Android
https://github.com/ArdWang/YModemlib_Android

anroid ymodem 实现单片机固件升级
https://www.jianshu.com/p/c36e0d0211e4

MCUUpdate
https://github.com/h4de5ing/MCUUpdate

SerialPortLib
https://github.com/h4de5ing/SerialPortLib

ymodem
https://github.com/aesirot/ymodem

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