Android ListView新活动启动

Question

我一直在尝试许多解决方案和代码组合，但我总是让我的进程在应用程序中被迫关闭。您有什么建议吗？

public class CompaniesViewActivity extends ListActivity {

    ArrayList<String> _listItems = new ArrayList<String>(); // Stores data from Company object
    ArrayList<String> _companyNames = new ArrayList<String>();
    ArrayAdapter<String> _adapter;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.companiesview_layout); // Setting the appropriate layout
        GlobalState globalState = (GlobalState)getApplicationContext(); // Setting the global vars
        ArrayList<Company> companies = globalState.loadCompanies(); // Retrieving the companies list
                                                                    // that was created during the
                                                                    // first view

        _adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, _listItems);
                                 // Constructing an ArrayAdapter in order to create a dynamic ListView
                                 // associated with the _listItems Dynamic String Array List
        setListAdapter(_adapter); // Setting the adapter
        addItems(companies); // Calls the method to add the items in the ListView
    }

    // Adding items to the ListView dynamically for all the companies in the retrieved companies list
    public void addItems(ArrayList<Company> companies) {
        for (int i=0; i<companies.size(); i++) {
            _listItems.add(companies.get(i).getName() + "\n" + "ΑΦΜ: " + companies.get(i).getVat());
            _companyNames.add(companies.get(i).getName());
            _adapter.notifyDataSetChanged(); // Refreshing the View with the data filled
        }
    }

    public void onListItemClick(ListView l, View v, int position, long id) {
    //String companyName = _companyNames.get(position);
    Intent intent = new Intent();
    intent.setClass(CompaniesViewActivity.this, CompanyTabViewActivity.class);
    startActivity(intent);
    //myIntent.putExtra("companyName", companyName);
    }
}

日志猫：

10-06 11:13:34.549: ERROR/AndroidRuntime(1569): FATAL EXCEPTION: main
10-06 11:13:34.549: ERROR/AndroidRuntime(1569): java.lang.RuntimeException: Unable to start activity ComponentInfo{gr.sigmasolutions/gr.sigmasolutions.CompanyTabViewActivity}: java.lang.RuntimeException: Unable to start activity ComponentInfo{gr.sigmasolutions/gr.sigmasolutions.CompanyInfoViewActivity}: java.lang.NullPointerException
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1622)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1638)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:928)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.os.Looper.loop(Looper.java:123)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.main(ActivityThread.java:3647)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at java.lang.reflect.Method.invokeNative(Native Method)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at java.lang.reflect.Method.invoke(Method.java:507)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at dalvik.system.NativeStart.main(Native Method)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{gr.sigmasolutions/gr.sigmasolutions.CompanyInfoViewActivity}: java.lang.NullPointerException
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1622)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1462)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:654)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.widget.TabHost.setCurrentTab(TabHost.java:326)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.widget.TabHost.addTab(TabHost.java:216)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at gr.sigmasolutions.CompanyTabViewActivity.onCreate(CompanyTabViewActivity.java:36)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1586)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     ... 11 more
10-06 11:13:34.549: ERROR/AndroidRuntime(1569): Caused by: java.lang.NullPointerException
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at gr.sigmasolutions.CompanyInfoViewActivity.showCompanyInfoServices(CompanyInfoViewActivity.java:54)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at gr.sigmasolutions.CompanyInfoViewActivity.onCreate(CompanyInfoViewActivity.java:32)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1586)
10-06 11:13:34.549: ERROR/AndroidRuntime(1569):     ... 20 more

Answer 1

Hear 是列表视图的最佳教程 http://www.vogella.de/articles/AndroidListView/文章.html
这可能有帮助...