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POAndroid: cannot update textView text dynamically from onTouchEvent
 

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  1. POAndroid: cannot update textView text dynamically from onTouchEvent
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    <p>I am working on an application that allows user to drag a dot on a screen and set the values of distance for example. What I want is to have half screen for drag function and the other half with gadgets (buttons and textViews). To do so I created a class extending SurfaceView, used a bitmap "dot" and the function onTouchEvent and in my xml file I referenced like following to my view:</p> <pre><code> &lt;test1.DragView android:id="@+id/view" android:layout_width="fill_parent" android:layout_height="fill_parent" /&gt; &lt;TextView android:id="@+id/textView" android:layout_width="fill_parent" android:layout_height="fill_parent" /&gt; </code></pre> <p>Which gives me what I want. But now I want to dynamically update the position of the dot. To do so I added setText() function for my textView in my onTouchEvent function:</p> <pre><code>@Override public boolean onTouchEvent(MotionEvent event) { x=(int)event.getX(); y=(int)event.getY(); bitmap =BitmapFactory.decodeResource(getResources(), R.drawable.dot); if(x&lt;0) x=0; if(x &gt; width+(bitmap.getWidth()/2)) x=width+(bitmap.getWidth()/2); if(y &lt;0) y=0; if(y &gt; height/2) y=height/2; tv=(TextView) findViewById(R.id.textView); //I declared tv in the beginning of my class tv.setText(x); updateBall(); //it's a function that resets the position of the dot return true; } </code></pre> <p>it gives me errors like </p> <pre><code>AndroidRuntime(845): FATAL EXCEPTION: main AndroidRuntime(845): java.lang.NullPointerException AndroidRuntime(845): at test1.DragView.onTouchEvent(DragView.java:87) AndroidRuntime(845): at android.view.View.dispatchTouchEvent(View.java:5462) AndroidRuntime(845): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1953) </code></pre> <p>I cannot use my textView in my DragView class. Is it normal? I can provide more explications if needed.</p> <p>EDIT: After using the solution of ReubenScratton I can acces my textView now but I'm getting the following error:</p> <pre><code>AndroidRuntime(672): FATAL EXCEPTION: main AndroidRuntime(672): android.content.res.Resources$NotFoundException: String resource ID #0x109 AndroidRuntime(672): at android.content.res.Resources.getText(Resources.java:247) AndroidRuntime(672): at android.widget.TextView.setText(TextView.java:3427) AndroidRuntime(672): at test1.DragView.onDraw(DragView.java:73) </code></pre>
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    1. USAnila
    1. USAnila
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    1. COit would be convinient if you can provide the piece of code where you call `setText()` and the logcat output.
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      1. POAndroid: cannot update textView text dynamically from onTouchEvent
      1. USmdelolmo
    2. CO"it gives me errors like NullPointerException" - how do you expect us to help if you don't provide the code that produces the NPE, and the stack trace of the exception? LogCat at least please
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      1. POAndroid: cannot update textView text dynamically from onTouchEvent
      1. USGuillaume
    3. CO@Guillaume you are right. I edited my question.
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      1. POAndroid: cannot update textView text dynamically from onTouchEvent
      1. USAnila
 

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