我正在编写一个Android应用程序。应用程序从主屏幕开始，然后单击按钮进入活动。我的代码没有任何错误，并且构建正常。但是，启动应用程序并单击按钮会导致崩溃。
My Manifest.XML
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidbtcontrol">
<uses-permission android:name="android.permission.BLUETOOTH" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".bluetoothconnect">
<intent-filter>
<action android:name="com.example.androidbtcontrol.bluetoothconnect" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
MainActivity.java
public void OnclickButtonListener(){
button_1 = (Button)findViewById(R.id.button);
button_1.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("com.example.androidbtcontrol.bluetoothconnect");
startActivity(intent);
}
}
);
}
}
bluetoothconnect.java
public class bluetoothconnect extends AppCompatActivity {
protected void onCreate3(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bluetoothconnect);
}
private static final int REQUEST_ENABLE_BT = 1;
BluetoothAdapter bluetoothAdapter;
ArrayList<BluetoothDevice> pairedDeviceArrayList;
TextView textInfo, textStatus;
ListView listViewPairedDevice;
RelativeLayout inputPane;
SeekBar barAnalogOut;
ArrayAdapter<BluetoothDevice> pairedDeviceAdapter;
private UUID myUUID;
private final String UUID_STRING_WELL_KNOWN_SPP =
"00001101-0000-1000-8000-00805F9B34FB";
ThreadConnectBTdevice myThreadConnectBTdevice;
ThreadConnected myThreadConnected;
protected void onCreate2(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textInfo = (TextView)findViewById(R.id.info);
textStatus = (TextView)findViewById(R.id.status);
listViewPairedDevice = (ListView)findViewById(R.id.pairedlist);
inputPane = (RelativeLayout) findViewById(R.id.inputpane);
if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH)){
Toast.makeText(this,
"FEATURE_BLUETOOTH NOT support",
Toast.LENGTH_LONG).show();
finish();
return;
}
//using the well-known SPP UUID
myUUID = UUID.fromString(UUID_STRING_WELL_KNOWN_SPP);
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (bluetoothAdapter == null) {
Toast.makeText(this,
"Bluetooth is not supported on this hardware platform",
Toast.LENGTH_LONG).show();
finish();
return;
}
String stInfo = bluetoothAdapter.getName() + "\n" +
bluetoothAdapter.getAddress();
textInfo.setText(stInfo);
barAnalogOut = (SeekBar)findViewById(R.id.analogOut);
barAnalogOut.setOnSeekBarChangeListener(OnAnalogOutChangeListener);
}
SeekBar.OnSeekBarChangeListener OnAnalogOutChangeListener =
new SeekBar.OnSeekBarChangeListener(){
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
//will generate too much data sent!
//SendAnalogOut(progress);
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
SendAnalogOut(seekBar.getProgress());
}
};
private final byte SYNC_BYTE = (byte) 0xAA;
private final byte LENGTH_ANALOG = (byte) 3;
private final byte CMD_ANALOG = (byte) 1;
private void SendAnalogOut(int val){
byte[] bytesToSend = {SYNC_BYTE, LENGTH_ANALOG, CMD_ANALOG, (byte) val};
myThreadConnected.write(bytesToSend);
}
@Override
protected void onStart() {
super.onStart();
//Turn ON BlueTooth if it is OFF
if (!bluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
}
setup();
}
private void setup() {
Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
pairedDeviceArrayList = new ArrayList<BluetoothDevice>();
for (BluetoothDevice device : pairedDevices) {
pairedDeviceArrayList.add(device);
}
pairedDeviceAdapter = new ArrayAdapter<BluetoothDevice>(this,
android.R.layout.simple_list_item_1, pairedDeviceArrayList);
listViewPairedDevice.setAdapter(pairedDeviceAdapter);
listViewPairedDevice.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
BluetoothDevice device =
(BluetoothDevice) parent.getItemAtPosition(position);
Toast.makeText(bluetoothconnect.this,
"Name: " + device.getName() + "\n"
+ "Address: " + device.getAddress() + "\n"
+ "BondState: " + device.getBondState() + "\n"
+ "BluetoothClass: " + device.getBluetoothClass() + "\n"
+ "Class: " + device.getClass(),
Toast.LENGTH_LONG).show();
textStatus.setText("start ThreadConnectBTdevice");
myThreadConnectBTdevice = new ThreadConnectBTdevice(device);
myThreadConnectBTdevice.start();
}
});
}
}
@Override
protected void onDestroy() {
super.onDestroy();
if(myThreadConnectBTdevice!=null){
myThreadConnectBTdevice.cancel();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(requestCode==REQUEST_ENABLE_BT){
if(resultCode == Activity.RESULT_OK){
setup();
}else{
Toast.makeText(this,
"BlueTooth NOT enabled",
Toast.LENGTH_SHORT).show();
finish();
}
}
}
//Called in ThreadConnectBTdevice once connect successed
//to start ThreadConnected
private void startThreadConnected(BluetoothSocket socket){
myThreadConnected = new ThreadConnected(socket);
myThreadConnected.start();
}
/*
ThreadConnectBTdevice:
Background Thread to handle BlueTooth connecting
*/
private class ThreadConnectBTdevice extends Thread {
private BluetoothSocket bluetoothSocket = null;
private final BluetoothDevice bluetoothDevice;
private ThreadConnectBTdevice(BluetoothDevice device) {
bluetoothDevice = device;
try {
bluetoothSocket = device.createRfcommSocketToServiceRecord(myUUID);
textStatus.setText("bluetoothSocket: \n" + bluetoothSocket);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void run() {
ToggleButton toggle = (ToggleButton) findViewById(R.id.toggleButton);
toggle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
if (isChecked) {
SendAnalogOut( 0);
// The toggle is enabled
} else {
SendAnalogOut( 255);
// The toggle is disabled
}
}
});
boolean success = false;
try {
bluetoothSocket.connect();
success = true;
} catch (IOException e) {
e.printStackTrace();
final String eMessage = e.getMessage();
runOnUiThread(new Runnable() {
@Override
public void run() {
textStatus.setText("Something wrong BluetoothSocket.connect(): \n" + eMessage);
}
});
try {
bluetoothSocket.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
if(success){
//connect successful
final String msgconnected = "Connect Successful:\n"
+ "BluetoothSocket: " + bluetoothSocket + "\n"
+ "BluetoothDevice: " + bluetoothDevice;
runOnUiThread(new Runnable(){
@Override
public void run() {
textStatus.setText(msgconnected);
listViewPairedDevice.setVisibility(View.GONE);
inputPane.setVisibility(View.VISIBLE);
}});
startThreadConnected(bluetoothSocket);
}else{
//fail
}
}
public void cancel() {
Toast.makeText(getApplicationContext(),
"close bluetoothSocket",
Toast.LENGTH_LONG).show();
try {
bluetoothSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
/*
ThreadConnected:
Background Thread to handle Bluetooth data communication
after connected
*/
private class ThreadConnected extends Thread {
private final BluetoothSocket connectedBluetoothSocket;
private final InputStream connectedInputStream;
private final OutputStream connectedOutputStream;
public ThreadConnected(BluetoothSocket socket) {
connectedBluetoothSocket = socket;
InputStream in = null;
OutputStream out = null;
try {
in = socket.getInputStream();
out = socket.getOutputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
connectedInputStream = in;
connectedOutputStream = out;
}
@Override
public void run() {
byte[] buffer = new byte[1024];
int bytes;
while (true) {
try {
bytes = connectedInputStream.read(buffer);
String strReceived = new String(buffer, 0, bytes);
final String msgReceived = String.valueOf(bytes) +
" bytes received:\n"
+ strReceived;
runOnUiThread(new Runnable() {
@Override
public void run() {
textStatus.setText(msgReceived);
}});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
final String msgConnectionLost = "Connection lost:\n"
+ e.getMessage();
runOnUiThread(new Runnable(){
@Override
public void run() {
textStatus.setText(msgConnectionLost);
}});
}
}
}
public void write(byte[] buffer) {
try {
connectedOutputStream.write(buffer);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void cancel() {
try {
connectedBluetoothSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
主要布局：
<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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="Please Choose "
android:textStyle="bold" />
<Button
android:text="Button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/button" />
</LinearLayout>
活动布局
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_bluetoothconnect"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.androidbtcontrol.bluetoothconnect">
<TextView
android:id="@+id/info"
android:textStyle="bold|italic"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/status"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<ListView
android:id="@+id/pairedlist"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<RelativeLayout
android:id="@+id/inputpane"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:visibility="gone">
</RelativeLayout>
<SeekBar
android:id="@+id/analogOut"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:max="99"
android:progress="0"/>
<ToggleButton
android:text="ToggleButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/toggleButton" />
</RelativeLayout>
答案 0 :(得分：0)
这些是我从您提供的信息中发现的一些错误。发布logcat异常详细信息，以便我可以优化此解决方案。
1）不要使用你自己的onCreate版本（在bluetoothactivity中）。活动应该只有一个 onCreate 方法。您还需要将 @Override 前缀添加到onCreate方法中。您拥有的代码包含 onCreate2 和 onCreate3 方法，这些方法都是错误的。 这可能是崩溃的原因，因为当调用蓝牙活动时，它无法找到onCreate方法。
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Keep your bluetooth related functionality here.
}
2）启动意图时，您还需要指定来源和目的地。
Intent intent = new Intent(CallingActivity.this,CalledActivity.class);
startActivity(intent);
答案 1 :(得分：0)
您的崩溃可能是由于您的意图，活动
造成的Intent intent = new Intent("com.example.androidbtcontrol.bluetoothconnect");
startActivity(intent);
正确的方式
Intent intent=new Intent(firstactivity.this,secondactivity.class);
startactivity(intent);
您需要指定目的地