App crash when button clicked using ontouchlistener
Question
my bluetooth app was going well until i used onTouchListener method , when i click on the bottom , the app crashes . I have several buttons and all of them end up crashing , bellow is part of my mainactivity code and the crash log, can you help me find the error? if the question is to vague or lacks information , please tell me .
public class MainActivity extends AppCompatActivity {
Button forward_btn,forward_left_btn , forward_right_btn , reverse_btn , reverse_right_btn , reverse_left_btn , btnConexao ;
public static final int SOLICITA_ATIVACAO = 1; // é o codigo numero 1 , é diferenciado o codigo pq pode haver varias solicitações na msma tela
public static final int SOLICITA_CONEXAO = 2;
BluetoothAdapter meuBluetoothAdapter=null; //declarar o meu adptador bluetooth
BluetoothDevice meuDevice=null;
BluetoothSocket meuSocket=null;// faz transiçao dos dados
boolean conexao = false; //variavel para a conexao que indica se a conexao está em andamento ou nao
private OutputStream outputStream;
private static String MAC = null;
String command; //string variable that will store value to be transmitted to the bluetooth module
UUID MEU_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); // canal de comunicaçao bluetooth , UUID- ID do canal
//protocolo Rfcomm
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
forward_btn = (Button) findViewById(R.id.forward_btn); //definir botoes e associar ao ficheiro xml
forward_left_btn = (Button) findViewById(R.id.forward_left_btn);
forward_right_btn = (Button) findViewById(R.id.forward_right_btn);
reverse_btn = (Button) findViewById(R.id.reverse_btn);
reverse_left_btn = (Button) findViewById(R.id.reverse_left_btn);
reverse_right_btn = (Button) findViewById(R.id.reverse_right_btn);
btnConexao = (Button) findViewById(R.id.btnConexao);
forward_btn.setOnTouchListener(new View.OnTouchListener() {
@Override
// comando para o botao frente , forward button
public boolean onTouch(View v, MotionEvent event) { // comandos bluetooth correspondentes do arduino
if (event.getAction() == MotionEvent.ACTION_DOWN) //MotionEvent.ACTION_DOWN é quando botao é segurado
{
command = "1";
try
{
outputStream.write(command.getBytes()); //transmite o valor do comando para o modulo bluetooth
}
catch (IOException e)
{
e.printStackTrace();
}
return true;
}
else if(event.getAction() == MotionEvent.ACTION_UP)
{
command = "10";
try
{
outputStream.write(command.getBytes());
}
catch(IOException e)
{
e.printStackTrace();
}
}
return false;
}
});
Crash log :
12-21 15:57:01.117 14520-14520/? I/art: Late-enabling -Xcheck:jni
12-21 15:57:01.117 14520-14520/? D/houdini: [14520] Initialize library(version: 5.0.7a_y.48167 RELEASE)... successfully.
12-21 15:57:01.184 14520-14520/com.example.noazevedo.appbluetoothfinal I/InstantRun: Instant Run Runtime started. Android package is com.example.noazevedo.appbluetoothfinal, real application class is null.
12-21 15:57:01.426 14520-14520/com.example.noazevedo.appbluetoothfinal V/Monotype: SetAppTypeFace- try to flip, app = com.example.noazevedo.appbluetoothfinal
12-21 15:57:01.427 14520-14520/com.example.noazevedo.appbluetoothfinal V/Monotype: Typeface getFontPathFlipFont - systemFont = default#default
12-21 15:57:01.430 14520-14520/com.example.noazevedo.appbluetoothfinal V/Monotype: SetAppTypeFace- try to flip, app = com.example.noazevedo.appbluetoothfinal
12-21 15:57:01.430 14520-14520/com.example.noazevedo.appbluetoothfinal V/Monotype: Typeface getFontPathFlipFont - systemFont = default#default
12-21 15:57:01.596 14520-14520/com.example.noazevedo.appbluetoothfinal W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
12-21 15:57:01.633 14520-14520/com.example.noazevedo.appbluetoothfinal V/Monotype: SetAppTypeFace- try to flip, app = com.example.noazevedo.appbluetoothfinal
12-21 15:57:01.634 14520-14520/com.example.noazevedo.appbluetoothfinal V/Monotype: Typeface getFontPathFlipFont - systemFont = default#default
12-21 15:57:01.873 14520-14584/com.example.noazevedo.appbluetoothfinal D/OpenGLRenderer: Render dirty regions requested: true
12-21 15:57:01.879 14520-14520/com.example.noazevedo.appbluetoothfinal D/Atlas: Validating map...
12-21 15:57:01.941 14520-14584/com.example.noazevedo.appbluetoothfinal I/OpenGLRenderer: Initialized EGL, version 1.4
12-21 15:57:01.942 14520-14584/com.example.noazevedo.appbluetoothfinal W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
12-21 15:57:01.952 14520-14584/com.example.noazevedo.appbluetoothfinal D/OpenGLRenderer: Enabling debug mode 0
12-21 15:57:13.907 14520-14520/com.example.noazevedo.appbluetoothfinal E/InputEventReceiver: Exception dispatching input event.
12-21 15:57:13.907 14520-14520/com.example.noazevedo.appbluetoothfinal E/MessageQueue-JNI: Exception in MessageQueue callback: handleReceiveCallback
12-21 15:57:13.909 14520-14520/com.example.noazevedo.appbluetoothfinal E/MessageQueue-JNI: java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.OutputStream.write(byte[])' on a null object reference
at com.example.noazevedo.appbluetoothfinal.MainActivity$1.onTouch(MainActivity.java:70)
at android.view.View.dispatchTouchEvent(View.java:8382)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2314)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1692)
at android.app.Activity.dispatchTouchEvent(Activity.java:2781)
at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:63)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2275)
at android.view.View.dispatchPointerEvent(View.java:8578)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4021)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3887)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3449)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3502)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3468)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3578)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3476)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3635)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3449)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3502)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3468)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3476)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3449)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5701)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5675)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5646)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:5791)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:143)
at android.os.Looper.loop(Looper.java:122)
at android.app.ActivityThread.main(ActivityThread.java:5264)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:900)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:695)
12-21 15:57:13.909 14520-14520/com.example.noazevedo.appbluetoothfinal D/AndroidRuntime: Shutting down VM
--------- beginning of crash
12-21 15:57:13.909 14520-14520/com.example.noazevedo.appbluetoothfinal E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.noazevedo.appbluetoothfinal, PID: 14520
java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.OutputStream.write(byte[])' on a null object reference
at com.example.noazevedo.appbluetoothfinal.MainActivity$1.onTouch(MainActivity.java:70)
at android.view.View.dispatchTouchEvent(View.java:8382)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2430)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2119)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2314)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1692)
at android.app.Activity.dispatchTouchEvent(Activity.java:2781)
at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:63)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2275)
at android.view.View.dispatchPointerEvent(View.java:8578)
at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4021)
at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3887)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3449)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3502)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3468)
at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3578)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3476)
at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:3635)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3449)
at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3502)
at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3468)
at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:3476)
at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3449)
at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:5701)
at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:5675)
at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:5646)
at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:5791)
at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
at android.os.MessageQueue.nativePollOnce(Native Method)
at android.os.MessageQueue.next(MessageQueue.java:143)
at android.os.Looper.loop(Looper.java:122)
at android.app.ActivityThread.main(ActivityThread.java:5264)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:900)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:695)
1 answers
solution1
2 2016-12-21 15:30:14
似乎您可能正在获取NPE，因为outputStream尚未初始化。
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.
Related Question
Why does my App crash, when a Button is clicked?
App stops unexpectedly when using OnTouchListener, MotionEvent.ACTION_UP
App Crashes when Button is Clicked
Android Studio. App crashes when only clicking button/imageview with onTouchListener
App crashed when the return button is clicked
When button clicked the app was Force Close
App keeps crashing when login button is clicked
specific button close the app when clicked
App crashes when TextInputLayout empty and button is clicked
Close the app when back button clicked twice
Related Tags