title: Android Swipe Images
body: <p>I'm trying to find a way to swipe images in my android application.I find a example of how to do that with textview,but I can't do the same thing with ImageView.Here is the original code with TextView :</p>
  
  <pre><code>HorizontalPager realViewSwitcher = new HorizontalPager(getApplicationContext());
  
  // Add some views to it
  final int[] backgroundColors =
          { Color.RED, Color.BLUE, Color.CYAN, Color.GREEN, Color.YELLOW };
  for (int i = 0; i &lt; 5; i++) {
      TextView textView = new TextView(getApplicationContext());
      textView.setText(Integer.toString(i + 1));
      textView.setTextSize(100);
      textView.setTextColor(Color.BLACK);
      textView.setGravity(Gravity.CENTER);
      textView.setBackgroundColor(backgroundColors[i]);
      realViewSwitcher.addView(textView);
  }
  
  // set as content view
  setContentView(realViewSwitcher);
  </code></pre>
  
  <p>and here is the code that I'm trying to do with ImageViews :</p>
  
  <pre><code>   HorizontalPager realViewSwitcher = new HorizontalPager(getApplicationContext());
      Map&lt;String, Integer&gt; map = new HashMap&lt;String, Integer&gt;();
      map.put("one", R.drawable.one);
      map.put("two", R.drawable.two);
      map.put("three", R.drawable.three);
  
      img1.setImageResource(map.get("one"));
      img2.setImageResource(map.get("two"));
      img3.setImageResource(map.get("three"));
      realViewSwitcher.addView(img1);
      realViewSwitcher.addView(img2);
      realViewSwitcher.addView(img3);
  
      setContentView(realViewSwitcher);
  </code></pre>
  
  <p>The images one,two,three are in drawable folder.When I use my code it's throwing me an Exception :</p>
  
  <p>LogCat:</p>
  
  <pre><code>08-09 09:21:24.097: ERROR/AndroidRuntime(743): Uncaught handler: thread main exiting due to uncaught exception
  08-09 09:21:24.115: ERROR/AndroidRuntime(743): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.stampii.stampii/com.stampii.stampii.cards.Cards}: java.lang.NullPointerException
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.os.Handler.dispatchMessage(Handler.java:99)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.os.Looper.loop(Looper.java:123)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.ActivityThread.main(ActivityThread.java:4363)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at java.lang.reflect.Method.invokeNative(Native Method)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at java.lang.reflect.Method.invoke(Method.java:521)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at dalvik.system.NativeStart.main(Native Method)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743): Caused by: java.lang.NullPointerException
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at com.stampii.stampii.cards.Cards.onCreate(Cards.java:30)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
  08-09 09:21:24.115: ERROR/AndroidRuntime(743):     ... 11 more
  </code></pre>
  
  <p>Any ideas how to get the things to work?</p>