Finding all occurrences of a substring in a string

Question

I'm trying to find all the lines that include the package name in the stacktrace that I am given. Here's what I have:

Log.d("result", result);
        ArrayList<String> allOccurences = new ArrayList<String>();
        int lastIndex = 0;
        int count = 0;
        String packageName = context.getPackageName();

        while(lastIndex != -1) {
            lastIndex = result.indexOf(packageName, lastIndex);
            if(lastIndex != -1) {
                String line = result.substring(lastIndex, packageName.length());
                allOccurences.add(line);
                lastIndex += packageName.length();
            }
        }

        for (int i = 0; i < allOccurences.size(); i++) {
            System.out.println(allOccurences.get(i));
        }

If I remove

String line = result.substring(lastIndex, packageName.length());
allOccurences.add(line);

it works just fine. I can't seem to figure out why. Any help?

Here's the stacktrace that i am searching:

06-18 20:43:59.455: D/result(1975): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.madqa/com.madqa.AndroidMADQAActivity}: java.lang.NullPointerException
06-18 20:43:59.455: D/result(1975):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
06-18 20:43:59.455: D/result(1975):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
06-18 20:43:59.455: D/result(1975):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
06-18 20:43:59.455: D/result(1975):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
06-18 20:43:59.455: D/result(1975):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-18 20:43:59.455: D/result(1975):     at android.os.Looper.loop(Looper.java:137)
06-18 20:43:59.455: D/result(1975):     at android.app.ActivityThread.main(ActivityThread.java:5041)
06-18 20:43:59.455: D/result(1975):     at java.lang.reflect.Method.invokeNative(Native Method)
06-18 20:43:59.455: D/result(1975):     at java.lang.reflect.Method.invoke(Method.java:511)
06-18 20:43:59.455: D/result(1975):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
06-18 20:43:59.455: D/result(1975):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
06-18 20:43:59.455: D/result(1975):     at dalvik.system.NativeStart.main(Native Method)
06-18 20:43:59.455: D/result(1975): Caused by: java.lang.NullPointerException
06-18 20:43:59.455: D/result(1975):     at com.madqa.AndroidMADQAActivity.onCreate(AndroidMADQAActivity.java:22)
06-18 20:43:59.455: D/result(1975):     at android.app.Activity.performCreate(Activity.java:5104)
06-18 20:43:59.455: D/result(1975):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
06-18 20:43:59.455: D/result(1975):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
06-18 20:43:59.455: D/result(1975):     ... 11 more

the package name is "com.madqa". There are 3 occurences in the stacktrace. I want to find them and print each one of them out. (it should print com.madqa 3 times)

What is it doing when it doens't work? – Vivin Paliath Jun 18 '14 at 20:40 — Vivin Paliath, Jun 18 '14 at 20:40
It only prints out the first occurrence – Nelson.b.austin Jun 18 '14 at 20:40 — Nelson.b.austin, Jun 18 '14 at 20:40
I don't see where you're printing out anything? – Vivin Paliath Jun 18 '14 at 20:41 — Vivin Paliath, Jun 18 '14 at 20:41

score 2 · Accepted Answer · answered Jun 18 '14 at 20:46

2

substring takes two indexes, not an index and a length. You need to add lastIndex to packageName.length(), like this:

String line = result.substring(lastIndex, lastIndex+packageName.length());

Once you make this change, your code should work.

Demo on ideone.

answered Jun 18 '14 at 20:46

Sergey Kalinichenko

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Thank you so much! Works perfectly! How did I not see that? It's been a long day haha – Nelson.b.austin Jun 18 '14 at 20:48

Finding all occurrences of a substring in a string

1 Answers1