Databases
StackOverflow2013
Postsdbo
POSharedPreferences NullPointer Exception, static and non-static method
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POSharedPreferences NullPointer Exception, static and non-static method
    primarykey
    data
    text
    <p>I am trying to draw a line graph using <em>afreechart</em> , I have saved the x and y points already using SharedPreferences. However, when I try to get some info from sharedpreferences i got an error, i suspect it has something to do with static and non-static methods not working together, but i cannot figure it out. </p> <p>So here's the class that where i add the x and y points:</p> <pre><code>public class DrawView extends DemoView{ static int round; static int score; public DrawView(Context context) { super(context); final AFreeChart chart = createChart(); setChart(chart); } private static XYSeriesCollection createDataset() { XYSeries xyS1 = new XYSeries("Progress", true, false); //Here I try to get the info from SharedPreferences via another class Stat t = new Stat(); round =t.getround(); for(int i = 0; i &lt; round; i++){ score = t.getscore(i); xyS1.add(i, score); } XYSeriesCollection xySC = new XYSeriesCollection(); xySC.addSeries(xyS1); return xySC; } /** * Creates a sample chart. * @param dataset the dataset. * @return A sample chart. */ private static AFreeChart createChart() { XYDataset dataset = createDataset(); AFreeChart chart = ChartFactory.createXYLineChart( "Statistics", "Rounds", "Points", dataset, PlotOrientation.VERTICAL, false, true, false); XYPlot plot = (XYPlot) chart.getPlot(); XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer(); renderer.setSeriesLinesVisible(0, true); plot.setRenderer(renderer); NumberAxis domainAxis = (NumberAxis) plot.getDomainAxis(); domainAxis.setUpperMargin(0.2); // add some annotations... XYTextAnnotation annotation = null; Font font = new Font("SansSerif", Typeface.NORMAL, 12); annotation = new XYTextAnnotation("Progress", 96, 57); annotation.setFont(font); annotation.setTextAnchor(TextAnchor.HALF_ASCENT_LEFT); plot.addAnnotation(annotation); return chart; } } </code></pre> <p>And here is the class via which I try to get info from SharePreferences :</p> <pre><code>public class Stat extends Activity { public static String filenamestat = "Stat"; SharedPreferences someStat; /** * Called when the activity is starting. * @param savedInstanceState */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); DrawView mView = new DrawView(this); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(mView); } public int getround(){ //Here is the error someStat = getSharedPreferences(filenamestat, 0); String roundtaker = someStat.getString("round", "0"); int round = Integer.parseInt(roundtaker); return round; } public int getscore(int a){ String scoretaker = Integer.toString(a); String stringscore = someStat.getString(scoretaker, "0"); int score = Integer.parseInt(stringscore); return score; } } </code></pre> <p>The LogCat</p> <pre><code>07-29 20:09:47.422: E/AndroidRuntime(414): FATAL EXCEPTION: main 07-29 20:09:47.422: E/AndroidRuntime(414): java.lang.RuntimeException: Unable to start activity ComponentInfo{at com.the.package/at com.the.package.Stat}: java.lang.NullPointerException 07-29 20:09:47.422: E/AndroidRuntime(414): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 07-29 20:09:47.422: E/AndroidRuntime(414): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 07-29 20:09:47.422: E/AndroidRuntime(414): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 07-29 20:09:47.422: E/AndroidRuntime(414): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 07-29 20:09:47.422: E/AndroidRuntime(414): at android.os.Handler.dispatchMessage(Handler.java:99) 07-29 20:09:47.422: E/AndroidRuntime(414): at android.os.Looper.loop(Looper.java:123) 07-29 20:09:47.422: E/AndroidRuntime(414): at android.app.ActivityThread.main(ActivityThread.java:4627) 07-29 20:09:47.422: E/AndroidRuntime(414): at java.lang.reflect.Method.invokeNative(Native Method) 07-29 20:09:47.422: E/AndroidRuntime(414): at java.lang.reflect.Method.invoke(Method.java:521) 07-29 20:09:47.422: E/AndroidRuntime(414): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 07-29 20:09:47.422: E/AndroidRuntime(414): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 07-29 20:09:47.422: E/AndroidRuntime(414): at dalvik.system.NativeStart.main(Native Method) 07-29 20:09:47.422: E/AndroidRuntime(414): Caused by: java.lang.NullPointerException 07-29 20:09:47.422: E/AndroidRuntime(414): at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:146) 07-29 20:09:47.422: E/AndroidRuntime(414): at at com.the.package.Stat.getround(Stat.java:33) 07-29 20:09:47.422: E/AndroidRuntime(414): at at com.the.package.DrawView.createDataset(DrawView.java:50) 07-29 20:09:47.422: E/AndroidRuntime(414): at at com.the.package.DrawView.createChart(DrawView.java:71) 07-29 20:09:47.422: E/AndroidRuntime(414): at com.the.package.DrawView.&lt;init&gt;(DrawView.java:38) 07-29 20:09:47.422: E/AndroidRuntime(414): at com.the.package.Stat.onCreate(Stat.java:26) </code></pre>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USHansUp
    1. USuser1506630
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POSharedPreferences NullPointer Exception, static and non-static method
      1. This table or related slice is empty.
      1. VTApproveEditSuggestion
    1. COWhich line is line 33 of class Stat?
      singulars
      1. POSharedPreferences NullPointer Exception, static and non-static method
      1. USghostbust555
    2. COsomeStat = getSharedPreferences(filenamestat, 0);
      singulars
      1. POSharedPreferences NullPointer Exception, static and non-static method
      1. USuser1506630
    3. COsomeStat is null,because you haven't added any value in it. See my answer
      singulars
      1. POSharedPreferences NullPointer Exception, static and non-static method
      1. USmoDev
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload