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

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

    ReplyDelete
    Replies
    1. 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 AppCompa

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

Simple ListView Adapter and list item select

When you are using a listview in your applications many a times you will write your own adapter to display item. But if your list is very simple showing a list of strings, you can use inbuilt adapters like ArrayAdapter, SimpleCursorAdapter etc. ArrayAdapter Let us look at an example <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ListView android:layout_height="wrap_content" android:id="@+id/listView1" android:layout_width="match_parent" android:layout_margin="20dp"> </ListView> </LinearLayout> And add these lines to the onCreate method of the activity. super.onCreate(savedInstanc