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有没有人遇到过这个问题。现在我正在尝试在 android 中显示条形图，但我通过使用它从 Web 服务获取 x 和 y 轴值。我通过 SOAP 方法使用它。这里我我遇到了这个问题，谁能告诉我如何克服这个问题？

LOGCAT

09-17 10:18:09.651: W/KeyCharacterMap(339): No keyboard for id 0
09-17 10:18:09.651: W/KeyCharacterMap(339): Using default keymap: /system/usr/keychars/qwerty.kcm.bin
09-17 10:18:20.450: D/AndroidRuntime(339): Shutting down VM
09-17 10:18:20.450: W/dalvikvm(339): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-17 10:18:20.460: E/AndroidRuntime(339): FATAL EXCEPTION: main
09-17 10:18:20.460: E/AndroidRuntime(339): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.xmlparsing_test/com.example.xmlparsing_test.BarGraphActivity}: java.lang.NullPointerException
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.os.Looper.loop(Looper.java:123)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.ActivityThread.main(ActivityThread.java:4627)
09-17 10:18:20.460: E/AndroidRuntime(339):  at java.lang.reflect.Method.invokeNative(Native Method)
09-17 10:18:20.460: E/AndroidRuntime(339):  at java.lang.reflect.Method.invoke(Method.java:521)
09-17 10:18:20.460: E/AndroidRuntime(339):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-17 10:18:20.460: E/AndroidRuntime(339):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-17 10:18:20.460: E/AndroidRuntime(339):  at dalvik.system.NativeStart.main(Native Method)
09-17 10:18:20.460: E/AndroidRuntime(339): Caused by: java.lang.NullPointerException
09-17 10:18:20.460: E/AndroidRuntime(339):  at com.example.xmlparsing_test.BarGraphActivity.buildBarDataset(BarGraphActivity.java:120)
09-17 10:18:20.460: E/AndroidRuntime(339):  at com.example.xmlparsing_test.BarGraphActivity.DrawGraph(BarGraphActivity.java:61)
09-17 10:18:20.460: E/AndroidRuntime(339):  at com.example.xmlparsing_test.BarGraphActivity.onCreate(BarGraphActivity.java:26)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-17 10:18:20.460: E/AndroidRuntime(339):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-17 10:18:20.460: E/AndroidRuntime(339):  ... 11 more

条形图活动.java

 public class BarGraphActivity extends Chart
 {

public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main1);

    Chart ch = new Chart();
    DrawGraph();
}

public void DrawGraph() 
{
String[] titles = new String[] { " Barcharts",""};

double[] x_axis = null;   
double[] y_axis = null;

List<double[]> values = new ArrayList<double[]>();

values.add(x_axis);
values.add(y_axis);

int[] colors = new int[] { Color.WHITE, Color.BLACK};

XYMultipleSeriesRenderer renderer = buildBarRenderer(colors);
renderer.setOrientation(Orientation.HORIZONTAL);

setChartSettings(renderer, "some texts", " ", " ",0,x_axis, 0,y_axis, Color.GRAY, Color.LTGRAY);
renderer.setXLabels(1);

renderer.addXTextLabel(1, "x_axis");
renderer.addYTextLabel(1, "y_axis");

renderer.setPanEnabled(true, false);

int length = renderer.getSeriesRendererCount();
for (int i = 0; i < length; i++) 
{
  SimpleSeriesRenderer seriesRenderer = renderer.getSeriesRendererAt(i);
  seriesRenderer.setDisplayChartValues(true);
  }

ChartFactory.getBarChartIntent(this, buildBarDataset(titles, values), renderer,Type.DEFAULT);
}

protected XYMultipleSeriesRenderer buildBarRenderer(int[] colors) 
{

        // creates a SeriesRenderer and initializes it with useful default values as well as colors

    XYMultipleSeriesRenderer renderer = new XYMultipleSeriesRenderer();

    renderer.setAxisTitleTextSize(15);
    renderer.setChartTitleTextSize(20);
    renderer.setLabelsTextSize(15);
    renderer.setLegendTextSize(15);

    int length = colors.length;
    for (int i = 0; i < length; i++) 
    {
      SimpleSeriesRenderer r = new SimpleSeriesRenderer();
      r.setColor(colors[i]);
      renderer.addSeriesRenderer(r);
    }
    return renderer;
  }

protected void setChartSettings(XYMultipleSeriesRenderer renderer, String title, String xTitle,
String yTitle, double xMin, double[] x_axis, double yMin, double[] y_axis, int axesColor,int labelsColor) 
 {
    // sets lots of default values for this renderer

renderer.setChartTitle(title);

renderer.setXTitle(xTitle);
renderer.setYTitle(yTitle);

renderer.setXAxisMin(xMin);

renderer.setYAxisMin(yMin);
renderer.setAxesColor(axesColor);
renderer.setLabelsColor(labelsColor);

renderer.setApplyBackgroundColor(true);
renderer.setBackgroundColor(Color.BLACK);
}

protected XYMultipleSeriesDataset buildBarDataset(String[] titles, List<double[]> values) 
{
        // adds the axis titles and values into the dataset

XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();

int length = titles.length;

for (int i = 0; i < length; i++) 
{
   CategorySeries series = new CategorySeries(titles[i]);

   double[] v = values.get(i);

   int seriesLength = v.length;

   for (int k = 0; k < seriesLength; k++) 
   {
     series.add(v[k]);
    }

   dataset.addSeries(series.toXYSeries());
   }
return dataset;
 }    }

感谢您宝贵的时间！..

4

1 回答 1

0

还有其他方法可以制作 Graph 你只需要这个方法还是你想要任何其他方法。？如果是的话，我会用一个新的来编辑我的答案Bar Graph Activity

于 2012-09-17T07:27:18.733 回答