NullPointerException in logcat trace

Question

Possible Duplicate:
NullpointerException when Launching activity

i get this logcat now !! every time i have this message and force close !! i asked this question before , but i get a new error ! exu !

FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{yaAli.package313.hossein110/yaAli.package313.hossein110.know}: java.lang.NullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
    at android.app.ActivityThread.access$2300(ActivityThread.java:125)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:4627)
    at java.lang.reflect.Method.invokeNative(Native Method)at java.lang.reflect.Method.invoke(Method.java:521)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
    at org.apache.harmony.luni.util.FloatingPointParser.parseFloat(FloatingPointParser.java:301)
    at java.lang.Float.parseFloat(Float.java:291)
    at java.lang.Float.valueOf(Float.java:330)
    at yaAli.package313.hossein110.know.onCreate(know.java:67)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
    ... 11 more

i get new logcat after applaying your answers :

FATAL EXCEPTION: main
java.lang.NumberFormatException: unable to parse '' as integer
at java.lang.Integer.parseInt(Integer.java:412)
at java.lang.Integer.parseInt(Integer.java:382)
at java.lang.Integer.valueOf(Integer.java:682)
at yaAli.package313.hossein110.know$1.run(know.java:37)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)

old question is : http://stackoverflow.com/questions/12749787/nullpointerexception-when-launching-activity — hkh114, Oct 05 '12 at 17:15
my code is in to link : http://stackoverflow.com/questions/12749787/nullpointerexception-when-launching-activity — hkh114, Oct 05 '12 at 17:18
You need to learn how to read a Logcat. In your new LogCat find the line that comes from your code: `at yaAli.package313.hossein110.know$1.run(know.java:37)`. You now know to focus on line 37 in `know.java`. Look back at your LogCat there are multiple line regarding `Integer.parseInt()` and the error involves an empty String... So on line 37 you and trying to turn an empty String into an Integer (you cannot do this). Once you learn how to read your LogCat you won't need to ask for help every time you have a bad line of code. — Sam, Oct 05 '12 at 17:37

Nathan Villaescusa · Answer 1 · 2012-10-05T17:27:50.067

4

From your code:

String sizefa = sharedpreferences.getString("fontsizefa",null);
...
tvfa.setTextSize(1, Float.valueOf(sizefa).floatValue());

When your preferences don't contain "fontsizefa" you are setting it to null. The exception is being thrown because later on you try to cast the null string to a float.

Change it to:

String sizefa = sharedpreferences.getString("fontsizefa","0.0");

or whatever you want the default size to be.

You are also going to have the same issue with colorfa when it is not in your preferences.

edited Oct 05 '12 at 17:27

answered Oct 05 '12 at 17:18

Nathan Villaescusa

17,331
4
53
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Is it due to `colorfa` being null? – Nathan Villaescusa Oct 05 '12 at 17:30
String colorfa= sharedpreferences.getString("fontcolorfa","#0276c0"); – hkh114 Oct 05 '12 at 17:32
Your new exception is being thrown by yaAli.package313.hossein110.know.run(). Looks like you are trying to parse a null string into an Integer. – Nathan Villaescusa Oct 05 '12 at 17:33
i cant find the null string !!! – hkh114 Oct 05 '12 at 17:48
whats the run() method ? – hkh114 Oct 05 '12 at 17:51
Whatever is on line 37 of know.java – Nathan Villaescusa Oct 05 '12 at 17:52
very very exu : how to see line number ? – hkh114 Oct 05 '12 at 17:55
if you say that how can see line number i say you whats it !! – hkh114 Oct 05 '12 at 17:58
If you are using Eclipse here is how to show line numbers http://stackoverflow.com/questions/640884/eclipse-line-numbers – Nathan Villaescusa Oct 05 '12 at 18:02
line 37 is : public void run() {s1.scrollTo(0, Integer.valueOf(ln));} });} – hkh114 Oct 05 '12 at 18:05
and i set String ln = null; – hkh114 Oct 05 '12 at 18:07
You can't convert a null into an integer, before that line check if ln is null and it it is don't attempt to scroll. – Nathan Villaescusa Oct 05 '12 at 18:09
ln=settings.getString("LASTREADln",""); if("-1".equals(ln)){ln="0";} if(ln!=null){ final ScrollView s1=(ScrollView) findViewById(R.id.sV1); s1.post(new Runnable() {@Override public void run() {s1.scrollTo(0, Integer.valueOf(ln));} });} – hkh114 Oct 05 '12 at 18:16
String ln = settings.getString("LASTREADln", null); int lnInt = (ln == null)? 0 : Integer.parseInt(ln); then use lnInt instead of ln; – Nathan Villaescusa Oct 05 '12 at 18:19

NullPointerException in logcat trace

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