App crushed when I type ' actionBar.setTitle("title");'

Question

When comment actionBar.setTitle("title");, the App runs normally.

What is causing my crash?

Here is a snippet of my AppCompatActivity:

public class ActionBar2 extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_action_bar);

        android.app.ActionBar actionBar = getActionBar();
        actionBar.setTitle("title");
    }
}

Here is the content of AndroidManifest.xml:

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

    <activity android:name=".ActionBar"></activity>

    <activity android:name=".ActionBar2">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

</application>

I just wonder if it is something wrong with my android studio ,or something else?Thandks a lot!

For `AppCompatActivity`, you need to use `getSupportActionBar()`. And the type is `android.support.v7.app.ActionBar`. — Mike M., Jan 19 '16 at 10:20
@gaomode for future reference, it is customary to include the stacktrace of the crash to help to diagnose it. — Knossos, Jan 19 '16 at 10:29
For the future reference don't name activity object with ActionBar2 name.. It is misleading and bad. Probably you are doing it with other objects as well — Ewoks, Jan 19 '16 at 10:34

score 2 · Accepted Answer · answered Jan 19 '16 at 10:26

2

public class TestActivity extends AppCompatActivity{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.test);
        ActionBar bar = getSupportActionBar();
        bar.setTitle("set title here");

    }
}

answered Jan 19 '16 at 10:26

Suhas Bachewar

1,230
7
21

@gaomode use Java naming convention in future. – Suhas Bachewar Jan 19 '16 at 10:39
Actually,I have named a lot of names(including this 'TestActivity').In the end ,I have no idea what name I can name ,so I used the 'ActionBar2'.Thanks for you advice! – gaomode Jan 19 '16 at 11:04

score 0 · Answer 2 · answered Jan 19 '16 at 10:33

0

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_action_bar);

    getSupportActionBar().setTitle("Set Your Title Here");
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setIcon(R.drawable.youricon);

     }

answered Jan 19 '16 at 10:33

Abhishek

1,654
2
18
31

Thanks a lot! When using 'ActionBar actionBar = getActionBar()',what should I do to make it run correctly? – gaomode Jan 19 '16 at 11:08
In AppCompatActivity you cannot add ActionBar like this you have to use getSupportActionBar() method for it. – Abhishek Jan 19 '16 at 11:12

App crushed when I type ' actionBar.setTitle("title");'

2 Answers2