在ActionBar中用中心标志显示ListActivity

Question

试图显示一个ActionBar与应用程序的标志左边，标题的屏幕为中心，菜单图标在右边。下面的类扩展了一个ListActivity，我可以这样做：

我创建的方法是centerlogo()；请参阅下面的代码摘录：

public class NewsActivity extends ListActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        ListView list;
        String[] itemname = { "Bafana crash out of Afcon",
                "Mali and Guinea face ultimate lottery",
                "Orlando Pirates eye cup glory",
                "Ivory Coast advance to Afcon quarters",
                "Algeria qualify for Afcon quarter-finals",
                "Reflect on Afcon lessons - Mbalula",
                "Tovey preaches patience with Bafana",
                "SuperSport's Brockie harbours lofty goals" };
        Integer[] imgid = { R.drawable.bafana, R.drawable.mailguinea,
                R.drawable.orlando, R.drawable.ivorycoast, R.drawable.algeria,
                R.drawable.reflection, R.drawable.tovey, R.drawable.supersport, };

        CustomListAdapter adapter = new CustomListAdapter(this, itemname, imgid);
        setListAdapter(adapter);


         centreLogo();
    }

    private void centreLogo() {
        // TODO Auto-generated method stub
                 Drawable d = getResources().getDrawable(R.drawable.banner);
     android.app.ActionBar bar = getActionBar();
     bar.setBackgroundDrawable(d);
     bar.setDisplayShowTitleEnabled(false);
     bar.setDisplayShowCustomEnabled(true);
     // getSupportActionBar().setDisplayHomeAsUpEnabled(true);
     bar.setCustomView(R.layout.news_view);
     bar.setDisplayShowHomeEnabled(true);
     bar.setIcon(R.drawable.icon);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu items for use in the action bar
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    public void readMore(View view) {
        Intent read = new Intent(NewsActivity.this, ReadMoreActivity.class);
        startActivity(read);
    }

}

我得到以下错误：

01-29 13:45:40.093: E/AndroidRuntime(15402): FATAL EXCEPTION: main
01-29 13:45:40.093: E/AndroidRuntime(15402): java.lang.RuntimeException: Unable to start activity ComponentInfo{platinum.platinumstars/platinumnews.NewsActivity}: java.lang.NullPointerException
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2245)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2295)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.app.ActivityThread.access$700(ActivityThread.java:150)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1280)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.os.Looper.loop(Looper.java:176)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at android.app.ActivityThread.main(ActivityThread.java:5279)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at java.lang.reflect.Method.invokeNative(Native Method)
01-29 13:45:40.093: E/AndroidRuntime(15402):    at java.lang.reflect.Method.invoke(Method.java:511)

Answer 1

我决定接受GareginSargsyan的建议。主要的问题是我试图膨胀默认的android列表，所以我实例化了一个新的ListView，设置了列表视图的ContentView，剩下的就是历史。

public class NewsActivity extends ActionBarActivity {
        ListView list;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_platinum_news_list);
            String[] itemname = { "Bafana crash out of Afcon",
                    "Mali and Guinea face ultimate lottery",
                    "Orlando Pirates eye cup glory",
                    "Ivory Coast advance to Afcon quarters",
                    "Algeria qualify for Afcon quarter-finals",
                    "Reflect on Afcon lessons - Mbalula",
                    "Tovey preaches patience with Bafana",
                    "SuperSport's Brockie harbours lofty goals" };
            Integer[] imgid = { R.drawable.bafana, R.drawable.mailguinea,
                    R.drawable.orlando, R.drawable.ivorycoast, R.drawable.algeria,
                    R.drawable.reflection, R.drawable.tovey, R.drawable.supersport, };

    //      CustomListAdapter adapter = new CustomListAdapter(this, itemname, imgid);
    //      setListAdapter(adapter);
            CustomListAdapter test = new CustomListAdapter(this, itemname, imgid);
            list = (ListView) findViewById(R.id.list);
            list.setAdapter(test);

             centreLogo();
        }



        private void centreLogo() {
            // TODO Auto-generated method stub
            Drawable d = getResources().getDrawable(R.drawable.banner);
            getSupportActionBar().setBackgroundDrawable(d);
            getSupportActionBar().setDisplayShowTitleEnabled(false);
            getSupportActionBar().setDisplayShowCustomEnabled(true);
            // getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            getSupportActionBar().setCustomView(R.layout.news_view);
            getSupportActionBar().setDisplayShowHomeEnabled(true);
            getSupportActionBar().setIcon(R.drawable.icon);
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu items for use in the action bar

             getMenuInflater().inflate(R.menu.newsmenu, menu);
                return true;
        }

        public void readMore(View view) {
            Intent read = new Intent(NewsActivity.this, ReadMoreActivity.class);
            startActivity(read);
        }

    }

Answer 2

很可能是getActionBar()导致了异常。尝试使用getSupportActionBar()代替。