小编chr*_*sse的帖子

我的Android项目总是出错.

java.lang.NullPointerException:尝试在空对象引用上调用虚方法'android.view.View android.app.Activity.findViewById(int)'

在我的MainActivity中,我正在调用FragmentStart类.

FragmentStart.class

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;

public class FragmentStart extends Fragment {

    //Define Listview
    private ListView startList;
    private String[] stringList;
    Activity activity = getActivity();

    public FragmentStart() {
        //
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_start, container, false);

        // Create ListView start
        startList = (ListView) rootView.findViewById(R.id.startList);
        stringList = getResources().getStringArray(R.array.startList);

        if (activity != …

public class CSVTeast {
  public static void main(String[] args) {

      CSVTeast obj = new CSVTeast();
        obj.run();

      }

      public void run() {

        String csvFile = "D:\\text.csv";
        BufferedReader br = null;
        String line = "";
        String cvsSplitBy = "~";

        try {

            br = new BufferedReader(new FileReader(csvFile));
            while ((line = br.readLine()) != null) {

                    // use comma as separator

                String[] csvRead = line.split(cvsSplitBy);




                System.out.println("Value [date= " + csvRead[5] 
                                     + " , name=" + csvRead[9]+"]");

            }

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch …

当我尝试在ubuntu 14.04中构建ambari版本2.4.1.0时,但是在构建ambari指标时失败,下面的grafana是我得到的错误,请建议我是否做错了用于构建指标的推荐是

 mvn -B clean install package jdeb:jdeb -DnewVersion=2.4.1.0.0 -DskipTests -Dpython.ver="python >= 2.6"


[INFO] --- jdeb:1.0.1:jdeb (default-cli) @ ambari-metrics-grafana ---
[WARNING] Creating empty debian package.
[ERROR] Failed to create debian package /home/hdfs/ambari/ambari/ambari-metrics/ambari-metrics-grafana/target/ambari-metrics-grafana_2.1.0.0.0_all.deb
org.vafer.jdeb.PackagingException: "/home/hdfs/ambari/ambari/ambari-metrics/ambari-metrics-grafana/src/main/package/deb/control" is not a valid 'control' directory)
        at org.vafer.jdeb.maven.DebMaker.makeDeb(DebMaker.java:186)
        at org.vafer.jdeb.maven.DebMojo.execute(DebMojo.java:409)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
        at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at …