Linux Process

June 27, 2019 · Grape

概念

程序是一系列指令的集合，通常存为可执行文件。进程是程序的执行过程。

进程属性

使用ps可以查看系统正在运行的进程。 ps --help显示该命令的用法。

ps -e -o USER,PID,PPID,GID,NAME
USER …

The Implementation Details of Android's force-stop

June 26, 2019 · 28 min read · Grape

基于AOSP 8.0.1源码分析force-stop的实现细节。

使用 force-stop

am force-stop com.example

com.example 是应用程序包名。

am命令

cat /system/bin/am
#!/system/bin/sh
if [ "$1" != "instrument" ] ; then
    cmd activity "$@"
else
    base=/system
    export CLASSPATH=$base/framework/am.jar
    exec app_process $base/bin com …

Debug Android Framework with Android Studio

June 05, 2019 · Grape

背景

在阅读Android Framework代码时，有时需要动态调试加深理解，或者想调试某个API的实现原理（如startActivity）时，希望可以使用Android Studio调试，且可以对应到源码的每一行 …

C++ 继承

May 27, 2019 · 7 min read · Grape

export NDK_ROOT=~/android-ndk-r18b

${NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
  --target=x86_64-none-linux-android
  --gcc-toolchain=${NDK_ROOT}/toolchains/x86_64-4.9/prebuilt/linux-x86_64
  --sysroot=${NDK_ROOT}/sysroot
  -isystem ${NDK_ROOT}/sysroot/usr/include/x86_64-linux-android
  -pie -o  hello.c.o -c hello.c

${NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
  --target=x86_64-none-linux-android
  --gcc-toolchain=${NDK_ROOT}/toolchains/x86_64-4.9 …

Android Unicode 字符串

May 24, 2019 · Grape

String16

// http://androidxref.com/6.0.1_r10/xref/system/core/libutils/String16.cpp#allocFromUTF8
static char16_t* allocFromUTF8(const char* u8str, size_t u8len)
{
    const ssize_t u16len = utf8_to_utf16_length(u8cur, u8len);
    utf8_to_utf16(u8cur …

Android 智能指针

May 24, 2019 · Grape

StrongPointer

INITIAL_STRONG_VALUE 为什么不是0 …

Android 源码开发

May 23, 2019 · 1 min read · Grape

准备开发环境

使用docker-aosp搭建

编译步骤

source build/envsetup.sh 
including device/asus/deb/vendorsetup.sh
including device/asus/flo/vendorsetup.sh
including device/asus/fugu/vendorsetup.sh
including device/generic/mini-emulator-arm64/vendorsetup.sh
including device/generic/mini-emulator-armv7-a-neon/vendorsetup.sh
including device/generic …

Docker 基础

May 23, 2019 · 2 min read · Grape

Dockerizing a Python Flask App

Install nginx 1.27.2

docker pull nginx:1.27.2
docker pull python:3.13

services:
  web:
    container_name: example_nginx
    image: nginx:1.27.2
    privileged: true
    ports:
      - 80:80
      - 443:443
    volumes:
      - "$PWD/html:/usr/share/nginx/html:rw"
      - "$PWD/conf/conf.d:/etc …

Android ClassLoader

May 15, 2019 · 1 min read · Grape

Class

// http://androidxref.com/6.0.1_r10/xref/libcore/libart/src/main/java/java/lang/Class.java
public final class Class<T> implements Serializable, AnnotatedElement, GenericDeclaration, Type {
    static native Class<?> classForName(String className, boolean shouldInitialize,
        ClassLoader classLoader) throws ClassNotFoundException;
}

VMClassLoader

// http://androidxref.com/6.0.1_r10/xref/libcore/libart/src …

Android ProgressBar Circle

May 13, 2019 · 1 min read · Grape

Shape

<?xml version="1.0" encoding="utf-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape=["rectangle" | "oval" | "line" | "ring"] 
    android:innerRadius="integer"
    android:innerRadiusRatio="integer"
    android:thickness="integer"
    android:thicknessRatio="integer"
    android:useLevel="boolean"
    >
    <corners
        android:radius="integer"
        android:topLeftRadius="integer"
        android:topRightRadius="integer"
        android:bottomLeftRadius …