下面给出的是MyActivity.java文件的代码。
package com.technomentis.ledonoff;
import java.io.IOException;
import java.io.OutputStream;
import java.util.UUID;
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.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
import android.R;
public class MainActivity extends Activity {
private static final String TAG = "LEDOnOff";
Button btnOn, btnOff;
private static final int REQUEST_ENABLE_BT = 1;
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private OutputStream outStream = null;
// Well known SPP UUID
private static final UUID MY_UUID =
UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// Insert your server's MAC address
private static String address = "00:00:00:00:00:00";
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "In onCreate()");
setContentView(R.layout.main);
btnOn = (Button) findViewById(R.id.btnOn);
btnOff = (Button) findViewById(R.id.btnOff);
btAdapter = BluetoothAdapter.getDefaultAdapter();
checkBTState();
btnOn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("1");
Toast msg = Toast.makeText(getBaseContext(),
"You have clicked On", Toast.LENGTH_SHORT);
msg.show();
}
});
btnOff.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
sendData("0");
Toast msg = Toast.makeText(getBaseContext(),
"You have clicked Off", Toast.LENGTH_SHORT);
msg.show();
}
});
}
@Override
public void onResume() {
super.onResume();
Log.d(TAG, "...In onResume - Attempting client connect...");
// Set up a pointer to the remote node using it's address.
BluetoothDevice device = btAdapter.getRemoteDevice(address);
// Two things are needed to make a connection:
// A MAC address, which we got above.
// A Service ID or UUID. In this case we are using the
// UUID for SPP.
try {
btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
}
// Discovery is resource intensive. Make sure it isn't going on
// when you attempt to connect and pass your message.
btAdapter.cancelDiscovery();
// Establish the connection. This will block until it connects.
Log.d(TAG, "...Connecting to Remote...");
try {
btSocket.connect();
Log.d(TAG, "...Connection established and data link opened...");
} catch (IOException e) {
try {
btSocket.close();
} catch (IOException e2) {
errorExit("Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + ".");
}
}
// Create a data stream so we can talk to server.
Log.d(TAG, "...Creating Socket...");
try {
outStream = btSocket.getOutputStream();
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and output stream creation failed:" + e.getMessage() + ".");
}
}
@Override
public void onPause() {
super.onPause();
Log.d(TAG, "...In onPause()...");
if (outStream != null) {
try {
outStream.flush();
} catch (IOException e) {
errorExit("Fatal Error", "In onPause() and failed to flush output stream: " + e.getMessage() + ".");
}
}
try {
btSocket.close();
} catch (IOException e2) {
errorExit("Fatal Error", "In onPause() and failed to close socket." + e2.getMessage() + ".");
}
}
private void checkBTState() {
// Check for Bluetooth support and then check to make sure it is turned on
// Emulator doesn't support Bluetooth and will return null
if(btAdapter==null) {
errorExit("Fatal Error", "Bluetooth Not supported. Aborting.");
} else {
if (btAdapter.isEnabled()) {
Log.d(TAG, "...Bluetooth is enabled...");
} else {
//Prompt user to turn on Bluetooth
Intent enableBtIntent = new Intent(btAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
}
private void errorExit(String title, String message){
Toast msg = Toast.makeText(getBaseContext(),
title + " - " + message, Toast.LENGTH_SHORT);
msg.show();
finish();
}
private void sendData(String message) {
byte[] msgBuffer = message.getBytes();
Log.d(TAG, "...Sending data: " + message + "...");
try {
outStream.write(msgBuffer);
} catch (IOException e) {
String msg = "In onResume() and an exception occurred during write: " + e.getMessage();
if (address.equals("00:00:00:00:00:00"))
msg = msg + ".\n\nUpdate your server address from 00:00:00:00:00:00 to the correct address on line 37 in the java code";
msg = msg + ".\n\nCheck that the SPP UUID: " + MY_UUID.toString() + " exists on server.\n\n";
errorExit("Fatal Error", msg);
}
}
}
我收到以下错误,
Error:(46, 32) error: cannot find symbol variable main
Error:(49, 43) error: cannot find symbol variable btnOn
Error:(50, 44) error: cannot find symbol variable btnOff
顺便说一下,我正在使用Android Studio。也是Android开发的新手。
答案 0 :(得分:0)
删除此行import android.R;
完成以下步骤: -
首先: - 将光标放在“R”文本上,它显示提示许多类型的包,然后选择你的包名,你的问题解决了。
第二: - 如果你的第一步没有工作,那么你再次实施项目。
我希望它对你有用。 :)
答案 1 :(得分:0)
删除此行..
import android.R;
并按CTRL + SHIFT + O修复导入。
答案 2 :(得分:0)
这意味着您缺少xml文件 main.xml中 点击右边的布局 - >新的aml文件 在其中,您必须在此xml文件上插入btnOn和btnoff按钮。