Android应用程序来使用硬件访问服务
Android应用程序来使用硬件访问服务
Android硬件访问服务: https://blog.csdn.net/qq_44226094/article/details/107380397
Android硬件抽象层模块: https://blog.csdn.net/qq_44226094/article/details/107370458
Android系统的硬件驱动 : https://blog.csdn.net/qq_44226094/article/details/107364659
在Android应用程序框架层开发硬件访问服务的目的是为了让上层的Android应用程序能够访问对应的硬件设备。
目录结构 :
~/Android/packages/experimental/Freg
# 配置文件
AndroidManifest.xml
Android.mk
# 源代码目录
src
shy/luo/freg
Freg.java
# 资源目录res
res
layout
main.xml
values
string.xml
drawable
icon.png
Freg.java :
// Android\packages\experimental\Freg\src\shy\luo\freg\Freg.java
public class Freg extends Activity implements OnClickListener
{
private final static String LOG_TAG = "shy.luo.freg.FregActivity";
private IFregService fregService = null;
private EditText valueText = null;
private Button readButton = null;
private Button writeButton = null;
private Button clearButton = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 将这个 Binder 代理对象接口转换为一个 FregService 代理对象接口，
//并且保存在 Activity 组件 Freg 的成员变量 fregService 中
fregService = IFregService.Stub.asInterface(
// 获得一个名称为“ freg ”的服务的 Binder 代理对象接口
ServiceManager.getService("freg"));
// 编辑框, 用来显示或者输入虚拟硬件设备freg的寄存器val的值
valueText = (EditText)findViewById(R.id.edit_value);
// 三个按钮Read、 Write和Clear
// 读虚拟硬件设备freg的寄存器val
readButton = (Button)findViewById(R.id.button_read);
// 写虚拟硬件设备freg的寄存器val
writeButton = (Button)findViewById(R.id.button_write);
// 清空编辑框
clearButton = (Button)findViewById(R.id.button_clear);
readButton.setOnClickListener(this);
writeButton.setOnClickListener(this);
clearButton.setOnClickListener(this);
Log.i(LOG_TAG, "Freg Activity Created");
}
@Override
public void onClick(View v)
{
if(v.equals(readButton))
{
try {
// 获取虚拟硬件设备freg的寄存器val的值
int val = fregService.getVal();
String text = String.valueOf(val);
valueText.setText(text);
} catch (RemoteException e) {
Log.e(LOG_TAG, "Remote Exception while reading value from freg service.");
}
}
else if(v.equals(writeButton))
{
try {
String text = valueText.getText().toString();
int val = Integer.parseInt(text);
// 设置虚拟硬件设备freg的寄存器val的值
fregService.setVal(val);
} catch (RemoteException e) {
Log.e(LOG_TAG, "Remote Exception while writing value to freg service.");
}
}
else if(v.equals(clearButton))
{
String text = "";
valueText.setText(text);
}
}
}
main.xml 主界面配置文件
<-- packages\experimental\Freg\res\layout\main.xml -->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" >
<-- 显示一个TextView控件 -->
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" android:gravity="center">
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/value">
</TextView>
<EditText android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="@+id/edit_value" android:hint="@string/hint">
</EditText>
</LinearLayout>
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center">
<-- 三个Button控件 -->
<Button android:id="@+id/button_read" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/read">
</Button>
<Button android:id="@+id/button_write" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/write">
</Button>
<Button android:id="@+id/button_clear" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/clear">
</Button>
</LinearLayout>
</LinearLayout>
strings.xml 字符串资源文件
<-- packages\experimental\Freg\res\values\string.xml -->
<?xml version="1.0" encoding="utf-8"?>
<-- 应用程序中使用到的各个字符串 -->
<resources>
<string name="app_name">Freg</string>
<string name="value">Value</string>
<string name="hint">Please input a value...</string>
<string name="read">Read</string>
<string name="write">Write</string>
<string name="clear">Clear</string>
</resources>
icon.png 图标文件
AndroidManifest.xml 配置文件
<-- /Android/packages/experimental/Freg/AndroidManifest.xml -->
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="shy.luo.freg" android:versionCode="1" android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<-- 定义了一个Activity组件 -->
<activity android:name=".Freg" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Android.mk 编译脚本文件
# ~/Android/packages/experimental/Freg/Android.mk
LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_SRC_FILES := $(call all-subdir-java-files)
# 指定程序的名称为“Freg”
LOCAL_PACKAGE_NAME := Freg
include $(BUILD_PACKAGE)
编译和打包
mmm ./packages/experimental/Freg/
make snod
打包后得到的Android系统镜像文件system.img就包含有应用程序Freg
启动
emulator -kernel kernel/goldfish/arch/arm/boot/zImage
由于个人水平有限, 难免有些错误, 希望各位点评
- @Author: cpu_code
- @Date: 2020-07-15 12:32:24
- @LastEditTime: 2020-07-16 13:44:47
- @FilePath: \notes\android_bottom\hardware_abstraction_layer\Android_application.md
- @Gitee: https://gitee.com/cpu_code
- @Github: https://github.com/CPU-Code
- @CSDN: https://blog.csdn.net/qq_44226094
- @Gitbook: https://923992029.gitbook.io/cpucode/
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