我正在使用eclipse和arduino开发一个连接到蓝牙模块的应用程序。然后我可以控制电路板上的LED。但是，我的代码显示没有错误，但每次按下按钮时应用程序强制关闭。这是我的代码：
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Button;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;
public class BluetoothTest extends Activity
{
TextView labelConnect;
BluetoothAdapter mBluetoothAdapter;
BluetoothSocket mmSocket;
BluetoothDevice mmDevice;
OutputStream mmOutputStream;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button openButton = (Button)findViewById(R.id.open);
Button closeButton = (Button)findViewById(R.id.close);
Button onButton = (Button)findViewById(R.id.onButton);
Button offButton = (Button)findViewById(R.id.offButton);
Button redButton = (Button)findViewById(R.id.redButton);
Button greenButton = (Button)findViewById(R.id.greenButton);
Button blueButton = (Button)findViewById(R.id.blueButton);
labelConnect = (TextView)findViewById(R.id.mylabel);
//Open Bluetooth
openButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
findBT();
openBT();
}
catch (IOException ex) { }
}
});
//Close Bluetooth
closeButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
closeBT();
}
catch (IOException ex) { }
}
});
//Red Button
redButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
redButton();
}
catch (IOException ex) { }
}
});
//Green Button
greenButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
greenButton();
}
catch (IOException ex) { }
}
});
//Blue Button
blueButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
try
{
blueButton();
}
catch (IOException ex) { }
}
});
//On Button - set strip to white
onButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
try {
onButton();
} catch (Exception e) {
// TODO: handle exception
}
}
});
//Off Button - set strip to all OFF
offButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
try {
offButton();
} catch (Exception e) {
// TODO: handle exception
}
}
});
} // end onCreate
void findBT()
{
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null)
{
labelConnect.setText("No bluetooth adapter available");
}
if(!mBluetoothAdapter.isEnabled())
{
Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBluetooth, 0);
}
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if(pairedDevices.size() > 0)
{
for(BluetoothDevice device : pairedDevices)
{
if(device.getName().equals("BTNode0")) // Change to match RN42 - node name
{
mmDevice = device;
Log.i("ArduinoBT", "findBT found device named " + mmDevice.getName());
Log.i("ArduinoBT", "device address is " + mmDevice.getAddress());
break;
}
}
}
labelConnect.setText("Bluetooth Device Found");
}
void openBT() throws IOException
{
UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); //Standard SerialPortService ID
mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
mmSocket.connect();
mmOutputStream = mmSocket.getOutputStream();
labelConnect.setText("BT << " + mmDevice.getName() + " >> is now open ");
}
void closeBT() throws IOException
{
mmOutputStream.close();
mmSocket.close();
labelConnect.setText("Bluetooth Closed");
}
void offButton() throws IOException
{
mmOutputStream.write("0".getBytes());
}
void redButton() throws IOException
{
mmOutputStream.write("1".getBytes());
}
void greenButton() throws IOException
{
mmOutputStream.write("2".getBytes());
}
void blueButton() throws IOException
{
mmOutputStream.write("3".getBytes());
}
void onButton() throws IOException
{
mmOutputStream.write("4".getBytes());
}
}
这是我点击连接按钮时发生的事情的日志
04-25 12:15:10.771: W/asset(22604): Copying FileAsset 0x74c0a9d8 (zip:/data/app/Android.Arduino.Bluetooth-2.apk:/resources.arsc) to buffer size 1912 to make it aligned.
04-25 12:15:10.821: D/RenderPolicy(22604): ViewRootImpl.enableHardwareAcceleration -> enableRenderPolicy
04-25 12:15:10.881: I/Adreno-EGL(22604): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build: (CL4169980)
04-25 12:15:10.881: I/Adreno-EGL(22604): OpenGL ES Shader Compiler Version: 17.01.10.SPL
04-25 12:15:10.881: I/Adreno-EGL(22604): Build Date: 02/04/14 Tue
04-25 12:15:10.881: I/Adreno-EGL(22604): Local Branch:
04-25 12:15:10.881: I/Adreno-EGL(22604): Remote Branch:
04-25 12:15:10.881: I/Adreno-EGL(22604): Local Patches:
04-25 12:15:10.881: I/Adreno-EGL(22604): Reconstruct Branch:
04-25 12:15:12.363: W/dalvikvm(22604): threadid=1: thread exiting with uncaught exception (group=0x41625e18)
04-25 12:15:12.373: E/AndroidRuntime(22604): FATAL EXCEPTION: main
04-25 12:15:12.373: E/AndroidRuntime(22604): Process: Android.Arduino.Bluetooth, PID: 22604
04-25 12:15:12.373: E/AndroidRuntime(22604): java.lang.NullPointerException
04-25 12:15:12.373: E/AndroidRuntime(22604): at Android.Arduino.Bluetooth.BluetoothTest.openBT(BluetoothTest.java:185)
04-25 12:15:12.373: E/AndroidRuntime(22604): at Android.Arduino.Bluetooth.BluetoothTest$1.onClick(BluetoothTest.java:53)
04-25 12:15:12.373: E/AndroidRuntime(22604): at android.view.View.performClick(View.java:4480)
04-25 12:15:12.373: E/AndroidRuntime(22604): at android.view.View$PerformClick.run(View.java:18673)
04-25 12:15:12.373: E/AndroidRuntime(22604): at android.os.Handler.handleCallback(Handler.java:733)
04-25 12:15:12.373: E/AndroidRuntime(22604): at android.os.Handler.dispatchMessage(Handler.java:95)
04-25 12:15:12.373: E/AndroidRuntime(22604): at android.os.Looper.loop(Looper.java:157)
04-25 12:15:12.373: E/AndroidRuntime(22604): at android.app.ActivityThread.main(ActivityThread.java:5872)
04-25 12:15:12.373: E/AndroidRuntime(22604): at java.lang.reflect.Method.invokeNative(Native Method)
04-25 12:15:12.373: E/AndroidRuntime(22604): at java.lang.reflect.Method.invoke(Method.java:515)
04-25 12:15:12.373: E/AndroidRuntime(22604): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1069)
04-25 12:15:12.373: E/AndroidRuntime(22604): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:885)
04-25 12:15:12.373: E/AndroidRuntime(22604): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
正如他们在评论中已经说过的那样，您在mmDevice方法中尝试使用的openBT为空，因为在findBT方法和变量中找不到任何设备没有初始化。您需要修复代码，以便在未找到设备时不要尝试打开连接。
一旦解决了这个问题，代码中的另一个主要问题是您尝试在主线程中打开的SocketConnection。按钮处理程序和GUI事件在主线程中执行，因此应将openBT移动到单独的线程（或更好的服务）。