我有一个服务，我从MainActivity开始。然后在onStartCommand（）中我注册到Broadcast Receivers。但是我将String值传递给Service by Bundle的广播接收器。但是我在广播接收器的onReceiver（）中得到NullpointerException。这是我的活动代码。
@Override
protected void onStart() {
super.onStart();
if (bluetoothService == null) {
kolamDeviceDialog();
} else {
Log.e("MenuBluetoothService", bluetoothService.getStatus() + "");
if (!bluetoothService.getStatus()) {
kolamDeviceDialog();
}
}
}
private void kolamDeviceDialog() {
MaterialDialog.Builder builder = new MaterialDialog.Builder(MenuActivity.this)
.title("Select Bot")
.items(scanTypes)
.itemsCallback(new MaterialDialog.ListCallback() {
@Override
public void onSelection(MaterialDialog dialog, View itemView, int position, CharSequence text) {
if (position == 0) {
isSmallBot = false;
KolamDevice kolamDevice = new KolamDevice();
Intent intent = new Intent(MenuActivity.this, BluetoothService.class);
intent.putExtra("Address", kolamDevice.getBigBotAddress());
intent.putExtra("Name", kolamDevice.getBigBotName());
startService(intent);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
} else {
isSmallBot = true;
KolamDevice kolamDevice = new KolamDevice();
Intent intent = new Intent(MenuActivity.this, BluetoothService.class);
intent.putExtra("Address", kolamDevice.getSmallBotAddress());
intent.putExtra("Name", kolamDevice.getSmallBotName());
startService(intent);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
}
});
builder.show();
}
@Override
protected void onStop() {
super.onStop();
if (mIsBound) {
unbindService(mConnection);
mIsBound = false;
}
}
这是我的服务代码。
public class BluetoothService extends Service {
private final IBinder mBinder = new MyBinder();
private SmoothBluetooth smoothBluetooth;
private static Device device;
String address, name;
private List<Integer> mBuffer = new ArrayList<>();
private List<String> mResponseBuffer = new ArrayList<>();
public BluetoothService() {
}
@Override
public void onCreate() {
super.onCreate();
Log.e("BluetoothService", "onCreated");
// startForeground(1, new Notification());
}
@Override
public void onDestroy() {
super.onDestroy();
Log.e("BluetoothService", "Killed");
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.e("BluetoothService", "Started");
startForeground(1, new Notification());
Bundle extras = intent.getExtras();
if (extras != null) {
address = extras.getString("Address");
name = extras.getString("Name");
}
Log.e("Address", address);
Log.e("name", name);
smoothBluetooth = new SmoothBluetooth(this);
smoothBluetooth.setListener(mListener);
startScheduleReceiver();
startBootReceiver();
if (smoothBluetooth.isBluetoothEnabled()) {
if (!smoothBluetooth.isConnected()) {
device = new Device(name, address, true);
smoothBluetooth.tryConnection();
}
} else {
device = new Device(name, address, true);
smoothBluetooth.tryConnection();
}
return Service.START_NOT_STICKY;
}
private void startBootReceiver() {
Intent broadcastIntent = new Intent(this, MyStartServiceReceiver.class);
Bundle bundle = new Bundle();
broadcastIntent.setAction(BluetoothAdapter.ACTION_STATE_CHANGED);
bundle.putString("BotType", name);
broadcastIntent.putExtras(bundle);
PendingIntent sender = PendingIntent.getBroadcast(this, 0, broadcastIntent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager service = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Calendar cal = Calendar.getInstance();
// start 1 second after boot completed
cal.add(Calendar.SECOND, 1);
// fetch every 1 second
// InexactRepeating allows Android to optimize the energy consumption
service.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), AlarmManager.INTERVAL_DAY, sender);
}
private void startScheduleReceiver() {
Intent broadcastIntent = new Intent(this, MyScheduleReceiver.class);
Bundle bundle = new Bundle();
broadcastIntent.setAction(BluetoothAdapter.ACTION_STATE_CHANGED);
bundle.putString("BotType", name);
broadcastIntent.putExtras(bundle);
PendingIntent sender = PendingIntent.getBroadcast(this, 0, broadcastIntent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager service = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Calendar cal = Calendar.getInstance();
// start 1 second after boot completed
cal.add(Calendar.SECOND, 1);
// fetch every 1 second
// InexactRepeating allows Android to optimize the energy consumption
service.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(), AlarmManager.INTERVAL_DAY, sender);
}
@Override
public IBinder onBind(Intent arg0) {
return mBinder;
}
public class MyBinder extends Binder {
BluetoothService getService() {
return BluetoothService.this;
}
}
public boolean getStatus() {
Log.e("BluetoothServiceStatus", smoothBluetooth.isConnected() + "");
return smoothBluetooth.isConnected();
}
这是我的第一个广播接收器代码。
public class MyStartServiceReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.e("BootReceiver", "Started");
Bundle bundle = intent.getExtras();
String name = bundle.getString("BotType");
if (name.equalsIgnoreCase("TEAMRED1")) {
KolamDevice kolamDevice = new KolamDevice();
Intent bigBotIntent = new Intent(context, BluetoothService.class);
bigBotIntent.putExtra("Address", kolamDevice.getBigBotAddress());
bigBotIntent.putExtra("Name", kolamDevice.getBigBotName());
context.startService(bigBotIntent);
} else {
KolamDevice kolamDevice = new KolamDevice();
Intent smallBotIntent = new Intent(context, BluetoothService.class);
smallBotIntent.putExtra("Address", kolamDevice.getSmallBotAddress());
smallBotIntent.putExtra("Name", kolamDevice.getSmallBotName());
context.startService(smallBotIntent);
}
}
}
这是我的第二个广播接收器代码。
public class MyScheduleReceiver extends BroadcastReceiver {
private String name, address;
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
Bundle bundle = intent.getExtras();
String smallBot = bundle.getString("BotType");
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
if (intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1) == BluetoothAdapter.STATE_ON) {
Log.e("BluetoothCondition", "On");
Log.e("Bot", smallBot);
} else if (intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1) == BluetoothAdapter.STATE_OFF) {
Log.e("BluetoothCondition", "Off");
Log.e("Bot", smallBot);
}
}
}
}
这也是logcat错误。
java.lang.RuntimeException: Unable to start receiver com.ignite.a01hw909350.kolamdemo.MyScheduleReceiver: java.lang.NullPointerException: println needs a message
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2645)
at android.app.ActivityThread.access$1800(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5290)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)
Caused by: java.lang.NullPointerException: println needs a message
at android.util.Log.println_native(Native Method)
at android.util.Log.e(Log.java:232)
at com.ignite.a01hw909350.kolamdemo.MyScheduleReceiver.onReceive(MyScheduleReceiver.java:28)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2638)
at android.app.ActivityThread.access$1800(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5290)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
请告诉我为什么我在两个广播接收器的onReceiver（）中都为空。
答案 0 :(得分：0)
您从服务到广播接收器的传递值是有问题的。
使用此：保持简单
对于接收者：
Intent broadcastIntent = new Intent(this, MyStartServiceReceiver.class);
broadcastIntent.setAction(BluetoothAdapter.ACTION_STATE_CHANGED);
broadcastIntent.putExtra("BotType", name);
//sendBroadcast(broadcastIntent);
现在在onReceive()
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
String smallBot = intent.getExtras().getString("BotType");
//do your stuff
}
}
另外添加：
if(smallBot!= null)
Log.e("Bot", smallBot);