Rockchip系列之深度分析CAN接口系列(1)_一歲抬頭的博客-CSDN博客
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Rockchip CAN 部分波特率收发不正常解决思路_一歲抬頭的博客-CSDN博客
Android JNI与CAN通信遇到的问题总结_android can通信-CSDN博客
Android 内核关闭CAN 串口设备回显功能_一歲抬頭的博客-CSDN博客
在上一篇博客中，介绍了如何在framework层编写一个服务类CanService，用于提供CAN通信的接口给其他应用程序或模块。还介绍了如何使用CanService类的封装类SystemCan，用于简化CAN通信的操作和配置。
在这篇博客中，将介绍如何在Android平台上开发一个App，用于测试和演示CAN通信的功能。将分别介绍App的界面设计，逻辑实现和使用方法。
这个App比较简单 只要核心接口写完了 应用端写成花都可以 目前实现了以下的功能：
- 可以选择不同的CAN设备和波特率，打开和关闭CAN总线
- 可以输入要发送的CAN数据，向CAN设备发送一帧数据
- 可以接收来自CAN设备的数据，并显示在列表中
- 可以清除已经接收到的数据
App的界面设计
使用Android Studio来开发的App，首先创建一个新的项目，命名为CanApp，并选择Empty Activity作为模板。然后，在res/layout/activity_main.xml文件中，定义了App的界面布局，如下所示：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="16dp"> <TextView android:id="@+id/canTextView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="CAN Interface:" android:textSize="18sp" /> <Spinner android:id="@+id/canSpinner" android:layout_width="match_parent" android:layout_height="wrap_content" /> <TextView android:id="@+id/baudrateTextView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Baudrate:" android:textSize="18sp" android:layout_marginTop="16dp" /> <Spinner android:id="@+id/baudrateSpinner" android:layout_width="match_parent" android:layout_height="wrap_content" /> <TextView android:id="@+id/dataTextView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Data:" android:textSize="18sp" android:layout_marginTop="16dp" /> <EditText android:id="@+id/dataEditText" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Enter data" android:text="1122334455667788" android:inputType="text" /> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content"> <Button android:id="@+id/sendButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Send" android:layout_margin="8dp" /> <Button android:id="@+id/openCanButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Open CAN" android:layout_margin="8dp" /> <Button android:id="@+id/closeCanButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Close CAN" android:layout_margin="8dp" /> <Button android:id="@+id/clearButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/openCanButton" android:layout_alignStart="@id/openCanButton" android:layout_margin="8dp" android:text="Clear Received Data" /> </LinearLayout> <ScrollView android:id="@+id/scrollView" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" android:fillViewport="true"> <ListView android:id="@+id/receivedDataListView" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" android:divider="@android:color/darker_gray" android:dividerHeight="0.5dp" android:padding="8dp" android:scrollbarStyle="outsideOverlay" android:scrollbars="vertical" /> </ScrollView> </LinearLayout>
这个布局文件定义了一个垂直方向的线性布局。
APP运行效果，如下图所示：
(我写这篇博客的时候 运行环境不在身边 截图以前的视频吧)
App的逻辑实现
在src/main/java/com/example/canapp/MainActivity.java文件中实现了App的逻辑功能，如下所示：
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener, View.OnClickListener { private static final String TAG = "MainActivity"; private static final int RECEIVE_CAN_DATA = 1; private Spinner canSpinner; private Spinner baudrateSpinner; private EditText dataEditText; private Button sendButton; private Button openCanButton; private Button closeCanButton; private Button clearButton; private ListView receivedDataListView; private ReceivedDataAdapter receivedDataAdapter; private ScrollView scrollView; private List<String> canList; private List<String> baudrateList; private String selectedCan; private int selectedBaudrate; private boolean isCanOpen = false; private SystemCan systemCan; private List<String> receivedDataList; private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { if (msg.what == RECEIVE_CAN_DATA) { Bundle bundle = msg.getData(); String data = bundle.getString("data"); String timestamp = getCurrentTimestamp(); String message = timestamp + " 收到数据: " + data; receivedDataList.add(message); receivedDataAdapter.notifyDataSetChanged(); scrollToBottom(); } } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); canSpinner = findViewById(R.id.canSpinner); baudrateSpinner = findViewById(R.id.baudrateSpinner); dataEditText = findViewById(R.id.dataEditText); sendButton = findViewById(R.id.sendButton); openCanButton = findViewById(R.id.openCanButton); closeCanButton = findViewById(R.id.closeCanButton); clearButton = findViewById(R.id.clearButton); receivedDataListView = findViewById(R.id.receivedDataListView); scrollView = findViewById(R.id.scrollView); canList = new ArrayList<>(); canList.add("can1"); canList.add("can0"); ArrayAdapter<String> canAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, canList); canAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); canSpinner.setAdapter(canAdapter); canSpinner.setOnItemSelectedListener(this); baudrateList = new ArrayList<>(); baudrateList.add("10000"); baudrateList.add("20000"); baudrateList.add("40000"); baudrateList.add("50000"); baudrateList.add("100000"); baudrateList.add("125000"); baudrateList.add("250000"); baudrateList.add("500000"); baudrateList.add("666000"); baudrateList.add("800000"); baudrateList.add("1000000"); ArrayAdapter<String> baudrateAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, baudrateList); baudrateAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); baudrateSpinner.setAdapter(baudrateAdapter); baudrateSpinner.setOnItemSelectedListener(this); sendButton.setOnClickListener(this); openCanButton.setOnClickListener(this); closeCanButton.setOnClickListener(this); clearButton.setOnClickListener(this); receivedDataList = new ArrayList<>(); receivedDataAdapter = new ReceivedDataAdapter(this, receivedDataList); receivedDataListView.setAdapter(receivedDataAdapter); // startCanReceiverThread(); } private void startCanReceiverThread() { Thread thread = new Thread(new Runnable() { @Override public void run() { new Thread() { long[] ret = new long[12]; @Override public void run() { while (true) { if (isCanOpen) { try { ret = systemCan.dev_receiveCan(systemCan.fd); } catch (RemoteException e) { e.printStackTrace(); } long canId = ret[0]; long canEff = ret[1]; long canRtr = ret[2]; long canLen = ret[3]; long[] canData = Arrays.copyOfRange(ret, 4, (int) (4 + canLen)); String str = "can RX "; str += (canEff == 0) ? "S " : "E "; str += (canRtr == 0) ? "- " : "R "; String canIdStr = Long.toHexString(canId); if (canEff == 0) { for (int i = 0; i < 3 - canIdStr.length(); i++) { canIdStr = '0' + canIdStr; } } else { for (int i = 0; i < 8 - canIdStr.length(); i++) { canIdStr = '0' + canIdStr; } } str = str + canIdStr + " [" + Long.toString(canLen) + "] "; for (int i = 0; i < canLen; i++) { String hex = Long.toHexString(canData[i]); hex = (hex.length() == 1) ? ('0' + hex) : hex; str = str + ' ' + hex; } str = str.toUpperCase(); str += '\n'; String finalStr = str; Log.d(TAG, "Received CAN data: " + finalStr); Message message = handler.obtainMessage(RECEIVE_CAN_DATA); Bundle bundle = new Bundle(); bundle.putString("data", finalStr); message.setData(bundle); handler.sendMessage(message); } } } }.start(); } }); thread.start(); } @Override protected void onDestroy() { super.onDestroy(); closeCan(); } @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { int viewId = parent.getId(); if (viewId == R.id.canSpinner) { selectedCan = canList.get(position); } else if (viewId == R.id.baudrateSpinner) { String selectedBaudrateStr = baudrateList.get(position); selectedBaudrate = Integer.parseInt(selectedBaudrateStr); } } @Override public void onNothingSelected(AdapterView<?> parent) { // Do nothing } @Override public void onClick(View v) { int viewId = v.getId(); if (viewId == R.id.sendButton) { sendCanData(); } else if (viewId == R.id.openCanButton) { openCan(); } else if (viewId == R.id.closeCanButton) { closeCan(); } else if (viewId == R.id.clearButton) { clearReceivedData(); } } private void sendCanData() { if (!isCanOpen) { showToast("请先打开 CAN 总线"); return; } String data = dataEditText.getText().toString().trim(); if (data.isEmpty()) { showToast("请输入要发送的数据"); return; } // Convert hex string to byte array byte[] dataArray = hexStringToByteArray(data); if (dataArray == null) { showToast("发送的数据格式不正确"); return; } try { int result = systemCan.dev_sendCan(systemCan.fd, 0, 0, 0, dataArray.length, byteArrayToIntArray(dataArray)); if (result != 0) { showToast("发送数据失败"); } else { showToast("发送数据成功"); } } catch (Exception e) { showToast("发送数据出现异常"); Log.e(TAG, "Error sending CAN data: " + e.getMessage()); } } private void openCan() { if (isCanOpen) { showToast("CAN 总线已经打开"); return; } try { systemCan = new SystemCan(selectedCan, selectedBaudrate); int fd = systemCan.dev_openCan(selectedCan); if (fd != -1) { systemCan.fd = fd; showToast("打开 CAN 总线成功"); openCanButton.setEnabled(false); isCanOpen = true; } else { showToast("打开 CAN 总线失败"); } } catch (Exception e) { showToast("打开 CAN 总线出现异常"); Log.e(TAG, "Error opening CAN: " + e.getMessage()); } // 添加了额外的参数tq（时间量化器），propSeg（传播段时间），phaseSeg1（相位段1时间），phaseSeg2（相位段2时间）和sjw（同步跳转宽度） /*runOnUiThread(new Runnable() { @Override public void run() { try { Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } ShellUtils.CommandResult commandResult = ShellUtils.execCommand("ip link set " + selectedCan + " down && ip link set " + selectedCan + " type can tq 133 prop-seg 6 phase-seg1 6 phase-seg2 2 sjw 1 && ip link set " + selectedCan + " up", true); //Log.d("SystemCan-test", + commandResult.result + "," + commandResult.successMsg + "," + commandResult.errorMsg); } });*/ } private void closeCan() { if (!isCanOpen) { showToast("CAN 总线已经关闭"); openCanButton.setEnabled(true); return; } try { int result = systemCan.dev_closeCan(systemCan.fd); if (result != 0) { showToast("关闭 CAN 总线失败"); } else { showToast("关闭 CAN 总线成功"); openCanButton.setEnabled(true); isCanOpen = false; } } catch (Exception e) { showToast("关闭 CAN 总线出现异常"); Log.e(TAG, "Error closing CAN: " + e.getMessage()); } } private void clearReceivedData() { receivedDataList.clear(); receivedDataAdapter.notifyDataSetChanged(); } private String getCurrentTimestamp() { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS"); return sdf.format(new Date()); } private void scrollToBottom() { scrollView.postDelayed(new Runnable() { @Override public void run() { scrollView.fullScroll(ScrollView.FOCUS_DOWN); } }, 100); }
在src/main/java/com/example/canapp/ReceivedDataAdapter.java文件中实现了App的can 接收数据DataAdapter功能，如下所示：
public class ReceivedDataAdapter extends ArrayAdapter<String> { private Context context; private List<String> dataList; public ReceivedDataAdapter(Context context, List<String> dataList) { super(context, 0, dataList); this.context = context; this.dataList = dataList; } @Override public int getCount() { return dataList.size(); } @Override public String getItem(int position) { return dataList.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; if (convertView == null) { convertView = LayoutInflater.from(context).inflate(R.layout.list_item_received_data, parent, false); viewHolder = new ViewHolder(); viewHolder.timestampTextView = convertView.findViewById(R.id.timestampTextView); viewHolder.dataTextView = convertView.findViewById(R.id.dataTextView); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder) convertView.getTag(); } String data = dataList.get(position); String[] parts = data.split("收到数据:"); String timestamp = parts[0]; String canData = parts[1]; viewHolder.timestampTextView.setText(timestamp); viewHolder.dataTextView.setText(canData); return convertView; } private static class ViewHolder { TextView timestampTextView; TextView dataTextView; } }
App的使用方法
可以使用Android Studio来运行的App，并在真机上进行测试。需要先打开CAN总线，然后输入要发送的数据，点击发送按钮，就可以向CAN设备发送一帧数据。还可以在ListView中查看接收到的数据列表，并清除已经接收到的数据。可以通过Spinner来切换不同的CAN设备和波特率，但是需要先关闭当前的CAN总线，再打开新的CAN总线。可以在Logcat中查看App的日志信息，以及发送和接收到的CAN数据。
我希望它能够帮助你和其他人了解和适配CAN通信的功能。如果你有任何问题，欢迎留言 & 支持三连 ~
