当他试图添加蓝牙时，我的联合队长很讨厌并打破了我的侦察应用程序。
每当我跑这个，我得到一个error that listview is null。 listview会弹出一个对话框，列出可以连接的可发现设备。我已经尝试在另一个帖子上更改每个指令的id，并确保在运行之前有可用的发现设备，但没有任何效果。请帮忙！这是我的
auto.Java:
private final BroadcastReceiver mBroadcastReceiver1 = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// When discovery finds a device
if (action.equals(mBluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, mBluetoothAdapter.ERROR);
switch (state) {
case BluetoothAdapter.STATE_OFF:
Log.d(TAG, "onReceive: STATE OFF");
break;
case BluetoothAdapter.STATE_TURNING_OFF:
Log.d(TAG, "mBroadcastReceiver1: STATE TURNING OFF");
break;
case BluetoothAdapter.STATE_ON:
Log.d(TAG, "mBroadcastReceiver1: STATE ON");
break;
case BluetoothAdapter.STATE_TURNING_ON:
Log.d(TAG, "mBroadcastReceiver1: STATE TURNING ON");
break;
}
}
}
};
private final BroadcastReceiver mBroadcastReceiver2 = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED)) {
int mode = intent.getIntExtra(BluetoothAdapter.EXTRA_SCAN_MODE, BluetoothAdapter.ERROR);
switch (mode) {
//Device is in Discoverable Mode
case BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE:
Log.d(TAG, "mBroadcastReceiver2: Discoverability Enabled.");
break;
//Device not in discoverable mode
case BluetoothAdapter.SCAN_MODE_CONNECTABLE:
Log.d(TAG, "mBroadcastReceiver2: Discoverability Disabled. Able to receive connections.");
break;
case BluetoothAdapter.SCAN_MODE_NONE:
Log.d(TAG, "mBroadcastReceiver2: Discoverability Disabled. Not able to receive connections.");
break;
case BluetoothAdapter.STATE_CONNECTING:
Log.d(TAG, "mBroadcastReceiver2: Connecting....");
break;
case BluetoothAdapter.STATE_CONNECTED:
Log.d(TAG, "mBroadcastReceiver2: Connected.");
break;
}
}
}
};
/**
* Broadcast Receiver that detects bond state changes (Pairing status changes)
*/
private BroadcastReceiver mBroadcastReceiver3 = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
Log.d(TAG, "onReceive: ACTION FOUND.");
if (action.equals(BluetoothDevice.ACTION_FOUND)) {
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
mBTDevices.add(device);
Log.d(TAG, "onReceive: " + device.getName() + ": " + device.getAddress());
mDeviceListAdapter = new DeviceListAdapter(context, R.layout.device_adapter_view, mBTDevices);
if(lvNewDevices == null)
{
Toast.makeText(getBaseContext(), " its null you fool and kaitlyn is the best", Toast.LENGTH_LONG).show();
}
else{
lvNewDevices.setAdapter(mDeviceListAdapter);
}
}
}
};
private final BroadcastReceiver mBroadcastReceiver4 = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED)) {
BluetoothDevice mDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
//3 cases:
//case1: bonded already
if (mDevice.getBondState() == BluetoothDevice.BOND_BONDED) {
Log.d(TAG, "BroadcastReceiver: BND_BONDED.");
mBTDevice = mDevice;
}
//case2: creating a bone
if (mDevice.getBondState() == BluetoothDevice.BOND_BONDING) {
Log.d(TAG, "BroadcastReceiver: BOND_BONDING.");
}
//case3: breaking a bond
if (mDevice.getBondState() == BluetoothDevice.BOND_NONE) {
Log.d(TAG, "BroadcastReceiver: BOND_NONE.");
}
}
}
};
@Override
protected void onDestroy() {
Log.d(TAG, "onDestroy: called.");
super.onDestroy();
/*unregisterReceiver(mBroadcastReceiver1);
unregisterReceiver(mBroadcastReceiver2);
unregisterReceiver(mBroadcastReceiver3);
unregisterReceiver(mBroadcastReceiver4);
mBluetoothAdapter.cancelDiscovery();*/
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button next = (Button) findViewById(R.id.auto);
next.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent myIntent = new Intent(view.getContext(), MainActivity.class);
startActivityForResult(myIntent, 0);
}
});
Button btnONOFF = (Button) findViewById(R.id.btnONOFF);
btnEnableDisable_Discoverable = (Button) findViewById(R.id.btnDiscoverable_on_off);
mBTDevices = new ArrayList<>();
// btnSend = (Button) findViewById(R.id.btnSend);
// etSend = (EditText) findViewById(R.id.editText);
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
registerReceiver(mBroadcastReceiver4, filter);
connectbtn = (Button) findViewById(R.id.connctbtn);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
lvNewDevices.setOnItemClickListener(Auto.this);
autoGearVal = (EditText) ((findViewById(R.id.autoGears)));
autoBallVal = (EditText) ((findViewById(R.id.autoBalls)));
match = (EditText) ((findViewById(R.id.matches)));
teamVal = (EditText) ((findViewById(R.id.team)));
textView = (TextView) findViewById(R.id.textView);
saveVal = (Button) findViewById(R.id.save);
btnStartConnection = (Button) findViewById(R.id.btnStartConnection);
File dir = new File(path);
dir.mkdirs();
spinner = (Spinner) findViewById(R.id.spinner);
final CheckBox checkBox = (CheckBox) findViewById(R.id.checkbox);
connectbtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final ConnectDialog connectDialog = new ConnectDialog();
View view = getLayoutInflater().inflate(R.layout.layout_dialog,null);
connectDialog.show(getSupportFragmentManager(), "Connect Dialog");
}
});
adapter = ArrayAdapter.createFromResource(this, R.array.Gear_Location, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
sideValue = String.valueOf(parent.getItemAtPosition(position));
Toast.makeText(getBaseContext(), parent.getItemAtPosition(position) + " selected", Toast.LENGTH_LONG).show();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
lvNewDevices = (ListView) findViewById(R.id.lvNewDevices);
}
public void send(String etSend) {
byte[] bytes = etSend.getBytes(Charset.defaultCharset());
mBluetoothConnection.write(bytes);
}
public void enableBT(View view) {
Log.d(TAG, "onClick: enabling/disabling bluetooth.");
enableDisableBT();
}
public void startConnection(View view) {
startBTConnection(mBTDevice, MY_UUID_INSECURE);
}
public void startBTConnection(BluetoothDevice device, UUID uuid) {
Log.d(TAG, "startBTConnection:Initializing RFCOM Bluetooth Connection.");
mBluetoothConnection.startClient(device, uuid);
}
public void enableDisableBT() {
if (mBluetoothAdapter == null) {
Log.d(TAG, "enableDisableBT: Does not have BT capabilities.");
}
if (!mBluetoothAdapter.isEnabled()) {
Log.d(TAG, "enableDisableBT: enabling BT.");
Intent enableBTIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivity(enableBTIntent);
IntentFilter BTIntent = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mBroadcastReceiver1, BTIntent);
}
if (mBluetoothAdapter.isEnabled()) {
Log.d(TAG, "enableDisableBT: disabling BT.");
mBluetoothAdapter.disable();
IntentFilter BTIntent = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mBroadcastReceiver1, BTIntent);
}
}
public void btnEnableDisable_Discoverable(View view) {
Log.d(TAG, "btnEnableDisable_Discoverable: Making device discoverable for 300 seconds.");
Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(discoverableIntent);
IntentFilter intentFilter = new IntentFilter(mBluetoothAdapter.ACTION_SCAN_MODE_CHANGED);
registerReceiver(mBroadcastReceiver2, intentFilter);
}
@RequiresApi(api = Build.VERSION_CODES.M)
public void btnDiscover(View view) {
Log.d(TAG, "btnDiscover: Looking for unpaired devices.");
if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
Log.d(TAG, "btnDiscover: Canceling discovery.");
//check BT permissions in manifest
checkBTPermissions();
mBluetoothAdapter.startDiscovery();
IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mBroadcastReceiver3, discoverDevicesIntent);
}
if (!mBluetoothAdapter.isDiscovering()) {
//check BT permissions in manifest
checkBTPermissions();
mBluetoothAdapter.startDiscovery();
IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mBroadcastReceiver3, discoverDevicesIntent);
}
}
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
//first cancel discovery because its very memory intensive.
mBluetoothAdapter.cancelDiscovery();
Log.d(TAG, "onItemClick: You Clicked on a device.");
String deviceName = mBTDevices.get(i).getName();
String deviceAddress = mBTDevices.get(i).getAddress();
Log.d(TAG, "onItemClick: deviceName = " + deviceName);
Log.d(TAG, "onItemClick: deviceAddress = " + deviceAddress);
//create the bond.
//NOTE: Requires API 17+? I think this is JellyBean
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2) {
Log.d(TAG, "Trying to pair with " + deviceName);
mBTDevices.get(i).createBond();
mBTDevice = mBTDevices.get(i);
mBluetoothConnection = new BluetoothConnectionService((Auto.this));
}
}
XML文件：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/lvNewDevices"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignTop="@+id/btnStartConnection"
android:layout_marginTop="11dp" />
"more nonsense about buttons"
</RelativeLayout>
错误：
12-17 21:40:00.405 13246-13246/com.example.owen.scoutingapp2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.owen.scoutingapp2, PID: 13246
java.lang.RuntimeException: Error receiving broadcast Intent { act=android.bluetooth.device.action.FOUND flg=0x10 bqHint=4 (has extras) } in com.example.owen.scoutingapp2.Auto$3@8132b08
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:1003)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7229)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
at com.example.owen.scoutingapp2.Auto$3.onReceive(Auto.java:151)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:993)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7229)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
auto.java.151：
lvNewDevices.setAdapter(mDeviceListAdapter);
我想我找到了。在这一行中，您尝试设置OnItemClickListener。但ListView尚未初始化：
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
registerReceiver(mBroadcastReceiver4, filter);
connectbtn = (Button) findViewById(R.id.connctbtn);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
lvNewDevices.setOnItemClickListener(Auto.this);
autoGearVal = (EditText) ((findViewById(R.id.autoGears)));
autoBallVal = (EditText) ((findViewById(R.id.autoBalls)));
在此之前，您需要设置字段'lvNewDevices'
lvNewDevices.setOnItemClickListener(Auto.this);
所以移动这一行
lvNewDevices = (ListView) findViewById(R.id.lvNewDevices);
在此
lvNewDevices.setOnItemClickListener(Auto.this);
然后再试一次。
女孩的位置