Skip to main content

Generate Random Numbers in Android

In your apps (especially in game apps) , you may come across the need to generate random numbers. For generation of psuedo random numbers you can use random class from package java.util

First of all you can construct a random number generator using this

        mRandom = new Random(seed);

The seed should be unique for better results. You can use current time for that

                    Time t = new Time();
        t.setToNow();
        mRandom = new Random(t.toMillis(false));

Now to generate a random number from 0 to n, you can use mRandom.nextInt(n). Make sure that n is not zero.
          int rand = mRandom.nextInt(10);

The above line generates a random number between 0 to 9.

Random class also provides other functions such as nextFloat(), nextDouble, nextLong.

Comments

  1. AnonymousJanuary 21, 2013 at 4:07 AM

    Could you please show how the whole java code file looks like with this code implemented. Thanks!

    ReplyDelete
  2. Sohammmm.....!!!February 14, 2013 at 9:25 PM

    How do i make sure that these random numbers r not repeatetive ???

    ReplyDelete
    Replies
    1. UnknownFebruary 14, 2013 at 10:39 PM

      I have been using it many times in my program and I rarely see repeated numbers. When you say something like random.nextInt(100), you do get a random number. If necessary, you can modify the seed by using random.setSeed(long), where you can use the current time as the seed value.

      Delete

Post a Comment

Popular posts from this blog

Copy to clipboard

In my upcoming app, I have codes which I display. These are some times lengthy, and I want the app to be able to copy this to clipboard. Once it is in clipboard, users can paste it anywhere. So how do you copy some text from your app to clipboard. You need to use clipboard manager. Clipboard Manager This class sets and gets data for the clipboard using Clipdata objects.  You can get the object of this class using system service.  - using statement context.getSystemService(Context.CLIPBOARD_SERVICE) Example I have a dummy project with a button, onclick of which copies content to clipboard. Here is my activity file package com . hegdeapps . testapp ; import android.content.ClipData ; import android.content.ClipboardManager ; import android.support.v7.app.AppCompatActivity ; import android.os.Bundle ; import android.view.View ; import android.widget.Button ; import android.widget.TextView ; public class MainActivity extends ...
Post a Comment
Read more

Drawables in Android - Layer drawable

Let us see how to use layer drawable. You can have two or more bitmaps on different layers to create such a drawable Using xml : You should use layer-list in your xml file to create layerdrawable. Here is layer.xml <?xml version="1.0" encoding="utf-8"?> <layer-list xmlns:android="http://schemas.android.com/apk/res/android"> <item> <bitmap android:src="@drawable/whiteicon" android:gravity="top|left"/> </item> <item> <bitmap android:src="@drawable/blueicon" android:gravity="top|left"/> </item> <item> <bitmap android:src="@drawable/redicon" android:gravity="top|left"/> </item> </layer-list> We are using three different bitmaps whiteicon.png, redicon.png and blueicon.png which are present in /res/drawable/mdpi folder. All these are of different sizes and aligned to top left. Thi...
1 comment
Read more

Using a list fragment with cursor adapter

All these days, I avoided using fragments. But then I realized for my this particular applications fragments are ideal. I have a master - detail list in my app. Let us say you want to have two fragments - one is a fragment which contains a list of elements and second one expands one element of the list. Both of them share the same cursor from the activity. Let us start with list fragment. Do not try creating list fragment using a wizard. It unnecearrily adds too many methods and classes. Let us start writing our own fragment like this class MyListFragment extends ListFragment { } Next using code menu override option, override the following method onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) This method should be used for inflating the layout file for the fragment.  I have a framelayout in parent activity of this fragment with the id as container. So I will specify that for inflating. The framelayout will be the paren...
Post a Comment
Read more