Merge pull request #2 from evision-ai/feat/add-listener-for-IOException

add a listener if read thread encounters IOException

Author: sabrinachen321

SerialPortLibrary/src/main/java/com/kongqw/serialportlibrary/SerialPortManager.java

@@ -198,6 +198,13 @@ public void onDataReceived(byte[] bytes) {
                     mOnSerialPortDataListener.onDataReceived(bytes);
                 }
             }
+
+            @Override
+            public void onIOException(IOException e) {
+                if (null != mOnSerialPortDataListener) {
+                    mOnSerialPortDataListener.onIOException(e);
+                }
+            }
         };
         mSerialPortReadThread.start();
     }

SerialPortLibrary/src/main/java/com/kongqw/serialportlibrary/listener/OnSerialPortDataListener.java

@@ -1,5 +1,7 @@
 package com.kongqw.serialportlibrary.listener;
 
+import java.io.IOException;
+
 /**
  * Created by Kongqw on 2017/11/14.
  * 串口消息监听
@@ -20,4 +22,9 @@ public interface OnSerialPortDataListener {
      * @param bytes 发送的数据
      */
     void onDataSent(byte[] bytes);
+
+    /**
+     * 串口读写过程中遇到IO异常
+     */
+    void onIOException(IOException e);
 }

SerialPortLibrary/src/main/java/com/kongqw/serialportlibrary/thread/SerialPortReadThread.java

@@ -1,5 +1,6 @@
 package com.kongqw.serialportlibrary.thread;
 
+import android.os.SystemClock;
 import android.util.Log;
 
 import java.io.IOException;
@@ -14,6 +15,7 @@
 public abstract class SerialPortReadThread extends Thread {
 
     public abstract void onDataReceived(byte[] bytes);
+    public abstract void onIOException(IOException e);
 
     private static final String TAG = SerialPortReadThread.class.getSimpleName();
     private InputStream mInputStream;
@@ -50,13 +52,14 @@ public void run() {
                 // 有的串口发送程序会产生一定的延迟，直接读取会导致串口消息分段
                 // 因此需要根据设置情况等待一段时间，保证发送端将消息发送完毕
                 if (mReadDelay > 0) {
-                    Thread.sleep(mReadDelay);
+                    SystemClock.sleep(mReadDelay);
                 }
 
                 // 读取串口输入
                 int size = mInputStream.read(mReadBuffer);
-                if (-1 == size || 0 >= size) {
-                    return;
+                if (0 >= size) {
+                    // 本次读取失败，重新等待输入
+                    continue;
                 }
 
                 byte[] readBytes = new byte[size];
@@ -66,7 +69,10 @@ public void run() {
                 Log.i(TAG, "run: readBytes = " + new String(readBytes));
                 onDataReceived(readBytes);
             } catch (IOException e) {
+                // 如果串口掉线会抛这个异常 java.io.IOException: I/O error
+                // 此时必须退出线程，因为即使设备再重新连上，也必须关闭输入流再重新打开
                 e.printStackTrace();
+                onIOException(e);
                 return;
             } catch (Exception e) {
                 e.printStackTrace();

app/src/main/java/com/kongqw/serialport/SerialPortActivity.java

@@ -16,14 +16,15 @@
 import com.kongqw.serialportlibrary.SerialPortManager;
 
 import java.io.File;
+import java.io.IOException;
 import java.util.Arrays;
 
 public class SerialPortActivity extends AppCompatActivity implements OnOpenSerialPortListener {
 
     private static final String TAG = SerialPortActivity.class.getSimpleName();
     public static final String DEVICE = "device";
     private SerialPortManager mSerialPortManager;
-
+    
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -66,6 +67,16 @@ public void run() {
                             }
                         });
                     }
+
+                    @Override
+                    public void onIOException(final IOException e) {
+                        runOnUiThread(new Runnable() {
+                            @Override
+                            public void run() {
+                                showToast("设备离线 " + e.getMessage());
+                            }
+                        });
+                    }
                 })
                 .openSerialPort(device.getFile(), 115200);