Android - GestureDetection force closing app
Question
I tried adding a GestureDetector in my app, so that when the user swipes from left to right, it goes to the next activity, and when the swipe right to left, the previous. Now, before doing that I wanted to test it using toasts. I built the code and tested it, but it just crashes when I simply touch the screen. I don't even have to swipe. Here is my code:
package com.cydeon.plasmamodz;
import java.io.File;
import com.koushikdutta.urlimageviewhelper.UrlImageViewHelper;
import android.app.ActionBar;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.Toast;
import android.view.GestureDetector.OnGestureListener;
import android.view.GestureDetector;
import android.os.*;
public class Softkeys extends Activity implements OnClickListener, OnGestureListener{
private GestureDetector gestureDetector;
private static final int SWIPE_MIN_DISTANCE = 150;
private static final int SWIPE_THRESHOLD_VELOCITY = 100;
/* (non-Javadoc)
* @see android.app.Activity#onCreate(android.os.Bundle)
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.themes);
ActionBar actionBar = getActionBar();
actionBar.hide();
RelativeLayout ll = (RelativeLayout) findViewById(R.id.myLayout);
final GestureDetector gestureDetector = new GestureDetector(Softkeys.this, this);
OnTouchListener gestureListener = new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
};
ll.setOnTouchListener(gestureListener);
int [] viewIds = new int [] {R.id.b1, R.id.b2, R.id.b3, R.id.b4, R.id.b5, R.id.b6, R.id.b7, R.id.b8, R.id.b9, R.id.b10, R.id.b11, R.id.b12, R.id.b13, R.id.b13, R.id.b14, R.id.b15, R.id.b16, R.id.b17, R.id.b18, R.id.b19, R.id.b20, R.id.b21, R.id.b22, R.id.b23, R.id.b24, R.id.b25, R.id.b26, R.id.b27, R.id.b28, R.id.b29, R.id.b30};
for(int i = 0; i < viewIds.length; i++){
View v = findViewById(viewIds[i]);
if (v != null) {
v.setVisibility(0);
}
}
Button stock = (Button) findViewById(R.id.b1);
stock.setBackgroundResource(R.drawable.soft_stock);
Button stockBlue = (Button) findViewById(R.id.b2);
stockBlue.setBackgroundResource(R.drawable.soft_stock_blue);
Button green = (Button) findViewById(R.id.b3);
green.setBackgroundResource(R.drawable.soft_green);
Button pink = (Button) findViewById(R.id.b4);
pink.setBackgroundResource(R.drawable.soft_pink);
Button purple = (Button) findViewById(R.id.b5);
purple.setBackgroundResource(R.drawable.soft_purple);
Button yellow = (Button) findViewById(R.id.b6);
yellow.setBackgroundResource(R.drawable.soft_yellow);
Button red = (Button) findViewById(R.id.b7);
red.setBackgroundResource(R.drawable.soft_red);
Button galaxy = (Button) findViewById(R.id.b8);
galaxy.setBackgroundResource(R.drawable.soft_galaxy);
Button galaxyBlue = (Button) findViewById(R.id.b9);
galaxyBlue.setBackgroundResource(R.drawable.soft_galaxy_blue);
Button reflect = (Button) findViewById(R.id.b10);
reflect.setBackgroundResource(R.drawable.soft_reflect);
Button reflectBlue = (Button) findViewById(R.id.b11);
reflectBlue.setBackgroundResource(R.drawable.soft_reflect_blue);
Button razor = (Button) findViewById(R.id.b12);
razor.setBackgroundResource(R.drawable.soft_razor);
Button razorBlue = (Button) findViewById(R.id.b13);
razorBlue.setBackgroundResource(R.drawable.soft_razor_blue);
Button small = (Button) findViewById(R.id.b14);
small.setBackgroundResource(R.drawable.soft_small);
Button smallBlue = (Button) findViewById(R.id.b15);
smallBlue.setBackgroundResource(R.drawable.soft_small_blue);
Button smallReflect = (Button) findViewById(R.id.b16);
smallReflect.setBackgroundResource(R.drawable.soft_small_reflect);
Button smallReflectBlue = (Button) findViewById(R.id.b17);
smallReflectBlue.setBackgroundResource(R.drawable.soft_small_reflect_blue);
Button xperia = (Button) findViewById(R.id.b18);
xperia.setBackgroundResource(R.drawable.soft_xperia);
Button blueXperia = (Button) findViewById(R.id.b19);
blueXperia.setBackgroundResource(R.drawable.soft_xperia_blue);
Button zte = (Button) findViewById(R.id.b20);
zte.setBackgroundResource(R.drawable.soft_zte);
Button zteBlue = (Button) findViewById(R.id.b21);
zteBlue.setBackgroundResource(R.drawable.soft_zte_blue);
Button college = (Button) findViewById(R.id.b22);
college.setBackgroundResource(R.drawable.soft_college);
Button collegeBlue = (Button) findViewById(R.id.b23);
collegeBlue.setBackgroundResource(R.drawable.soft_college_blue);
Button defused = (Button) findViewById(R.id.b24);
defused.setBackgroundResource(R.drawable.soft_defused);
Button defusedBlue = (Button) findViewById(R.id.b25);
defusedBlue.setBackgroundResource(R.drawable.soft_defused_blue);
Button droid = (Button) findViewById(R.id.b26);
droid.setBackgroundResource(R.drawable.soft_droid);
Button droidBlue = (Button) findViewById(R.id.b27);
droidBlue.setBackgroundResource(R.drawable.soft_droid_blue);
Button pixel = (Button) findViewById(R.id.b28);
pixel.setBackgroundResource(R.drawable.soft_pixel);
Button pixelBlue = (Button) findViewById(R.id.b29);
pixelBlue.setBackgroundResource(R.drawable.soft_pixel_blue);
Button facebook = (Button) findViewById(R.id.b30);
facebook.setBackgroundResource(R.drawable.soft_facebook);
int [] viewIds2 = new int [] {R.id.b1, R.id.b2, R.id.b3, R.id.b4, R.id.b5, R.id.b6, R.id.b7, R.id.b8, R.id.b9, R.id.b10, R.id.b11, R.id.b12, R.id.b13, R.id.b13, R.id.b14, R.id.b15, R.id.b16, R.id.b17, R.id.b18, R.id.b19, R.id.b20, R.id.b21, R.id.b22, R.id.b23, R.id.b24, R.id.b25, R.id.b26, R.id.b27, R.id.b28, R.id.b29, R.id.b30};
for(int i = 0; i < viewIds2.length; i++){
View v = findViewById(viewIds2[i]);
if (v != null) {
v.setOnClickListener(this);
}
}
}
@Override
public void onClick(View arg0) {
Intent a = new Intent(Softkeys.this, Bmod.class);
if (arg0.getId() == R.id.b1) {
a.putExtra("Stock", "stock");
startActivity(a);
} else if (arg0.getId() == R.id.b2) {
a.putExtra("StockBlue", "stockblue");
startActivity(a);
} else if (arg0.getId() == R.id.b3) {
a.putExtra("Green", "green");
startActivity(a);
} else if (arg0.getId() == R.id.b4) {
a.putExtra("Pink", "pink");
startActivity(a);
} else if (arg0.getId() == R.id.b5) {
a.putExtra("Purple", "purple");
startActivity(a);
} else if (arg0.getId() == R.id.b6) {
a.putExtra("Yellow", "yellow");
startActivity(a);
} else if (arg0.getId() == R.id.b7) {
a.putExtra("Red", "red");
startActivity(a);
} else if (arg0.getId() == R.id.b8) {
a.putExtra("Galaxy", "galaxy");
startActivity(a);
} else if (arg0.getId() == R.id.b9) {
a.putExtra("GalaxyBlue", "galaxyblue");
startActivity(a);
} else if (arg0.getId() == R.id.b10) {
a.putExtra("Reflect", "Reflect");
startActivity(a);
} else if (arg0.getId() == R.id.b11) {
a.putExtra("ReflectBlue", "reflect");
startActivity(a);
} else if (arg0.getId() == R.id.b12) {
a.putExtra("Razor", "razor");
startActivity(a);
} else if (arg0.getId() == R.id.b13) {
a.putExtra("RazorBlue", "razorblue");
startActivity(a);
} else if (arg0.getId() == R.id.b14) {
a.putExtra("Small", "small");
startActivity(a);
} else if (arg0.getId() == R.id.b15) {
a.putExtra("SmallBlue", "smallblue");
startActivity(a);
} else if (arg0.getId() == R.id.b16) {
a.putExtra("SmallReflect", "smallreflect");
startActivity(a);
} else if (arg0.getId() == R.id.b17) {
a.putExtra("SmallReflectBlue", "smallreflectblue");
startActivity(a);
} else if (arg0.getId() == R.id.b18) {
a.putExtra("Xperia", "xperia");
startActivity(a);
} else if (arg0.getId() == R.id.b19) {
a.putExtra("XperiaBlue", "xperiablue");
startActivity(a);
} else if (arg0.getId() == R.id.b20) {
a.putExtra("Zte", "zte");
startActivity(a);
} else if (arg0.getId() == R.id.b21) {
a.putExtra("ZteBlue", "zteblue");
startActivity(a);
} else if (arg0.getId() == R.id.b22) {
a.putExtra("College", "college");
startActivity(a);
} else if (arg0.getId() == R.id.b23) {
a.putExtra("CollegeBlue", "collegeblue");
startActivity(a);
} else if (arg0.getId() == R.id.b24) {
a.putExtra("Defused", "defused");
startActivity(a);
} else if (arg0.getId() == R.id.b25) {
a.putExtra("DefusedBlue", "defusedblue");
startActivity(a);
} else if (arg0.getId() == R.id.b26) {
a.putExtra("Droid", "droid");
startActivity(a);
} else if (arg0.getId() == R.id.b27) {
a.putExtra("DroidBlue", "droidblue");
startActivity(a);
} else if (arg0.getId() == R.id.b28) {
a.putExtra("Pixel", "pixel");
startActivity(a);
} else if (arg0.getId() == R.id.b29) {
a.putExtra("PixelBlue", "pixelsblue");
startActivity(a);
} else if (arg0.getId() == R.id.b30){
a.putExtra("Facebook", "facebook");
startActivity(a);
}
}
@Override
public boolean onDown(MotionEvent arg0) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Toast.makeText(Softkeys.this, "Right to left",
Toast.LENGTH_LONG).show();
Log.i("tag", "Right to left");
return true; // Right to left
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Toast.makeText(Softkeys.this, "Left to right",
Toast.LENGTH_LONG).show();
Log.i("tag", "Left to right");
return true; // Left to right
}
return false;
}
@Override
public void onLongPress(MotionEvent arg0) {
Intent in = new Intent(Softkeys.this, MainActivity.class);
startActivity(in);
}
@Override
public boolean onScroll(MotionEvent arg0, MotionEvent arg1, float arg2,
float arg3) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onShowPress(MotionEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public boolean onSingleTapUp(MotionEvent arg0) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onTouchEvent(MotionEvent me) {
return gestureDetector.onTouchEvent(me);
}
}
Sorry, it's sorta big. Anyways, here's the log:
04-10 22:34:28.221: E/InputEventReceiver(3256): Exception dispatching input event.
04-10 22:34:28.221: E/MessageQueue-JNI(3256): Exception in MessageQueue callback: handleReceiveCallback
04-10 22:34:28.221: E/MessageQueue-JNI(3256): java.lang.NullPointerException
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at com.cydeon.plasmamodz.Softkeys.onTouchEvent(Softkeys.java:282)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.app.Activity.dispatchTouchEvent(Activity.java:2413)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2120)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.View.dispatchPointerEvent(View.java:7426)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3220)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3165)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4292)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4271)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4363)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:179)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.os.MessageQueue.nativePollOnce(Native Method)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.os.MessageQueue.next(MessageQueue.java:125)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.os.Looper.loop(Looper.java:124)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at android.app.ActivityThread.main(ActivityThread.java:5235)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at java.lang.reflect.Method.invokeNative(Native Method)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at java.lang.reflect.Method.invoke(Method.java:511)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
04-10 22:34:28.221: E/MessageQueue-JNI(3256): at dalvik.system.NativeStart.main(Native Method)
04-10 22:34:28.229: E/AndroidRuntime(3256): FATAL EXCEPTION: main
04-10 22:34:28.229: E/AndroidRuntime(3256): java.lang.NullPointerException
04-10 22:34:28.229: E/AndroidRuntime(3256): at com.cydeon.plasmamodz.Softkeys.onTouchEvent(Softkeys.java:282)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.app.Activity.dispatchTouchEvent(Activity.java:2413)
04-10 22:34:28.229: E/AndroidRuntime(3256): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2120)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.View.dispatchPointerEvent(View.java:7426)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3220)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3165)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4292)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4271)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4363)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:179)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.os.MessageQueue.nativePollOnce(Native Method)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.os.MessageQueue.next(MessageQueue.java:125)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.os.Looper.loop(Looper.java:124)
04-10 22:34:28.229: E/AndroidRuntime(3256): at android.app.ActivityThread.main(ActivityThread.java:5235)
04-10 22:34:28.229: E/AndroidRuntime(3256): at java.lang.reflect.Method.invokeNative(Native Method)
04-10 22:34:28.229: E/AndroidRuntime(3256): at java.lang.reflect.Method.invoke(Method.java:511)
04-10 22:34:28.229: E/AndroidRuntime(3256): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
04-10 22:34:28.229: E/AndroidRuntime(3256): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
04-10 22:34:28.229: E/AndroidRuntime(3256): at dalvik.system.NativeStart.main(Native Method)
1 answers
solution1
1 ACCPTED 2013-04-11 02:58:30
You initialized gestureDetector which is a local variable of onCreate() .
Just remove this keyword final GestureDetector
private GestureDetector gestureDetector;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.themes);
ActionBar actionBar = getActionBar();
actionBar.hide();
RelativeLayout ll = (RelativeLayout) findViewById(R.id.myLayout);
gestureDetector = new GestureDetector(Softkeys.this, this);
/* Your stuff */
}
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