代码帮助我更改了标题。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_name);
    ActivityName.this.setTitle("Your Activity Title");}

如果你想要它一次，让系统处理剩下的(不是动态的)，那么在你的manifest文件中这样做:

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name_full" > //This is my custom title name on activity. <- The question is about this one.
            <intent-filter android:label="@string/app_launcher_name" > //This is my custom Icon title name (launcher name that you see in android apps/homescreen)
                <action android:name="android.intent.action.MAIN" />

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

如果你有多个活动，你可以在AndroidManifest.xml中这样设置

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".NumbersActivity"
        android:label="@string/category_numbers"
        android:theme="@style/category_numbers" />
    <activity
        android:name=".FamilyActivity"
        android:label="@string/category_family"
        android:theme="@style/category_family" />
    <activity
        android:name=".ColorsActivity"
        android:label="@string/category_colors"
        android:theme="@style/category_colors" />
    <activity
        android:name=".PhrasesActivity"
        android:label="@string/category_phrases"
        android:theme="@style/category_phrases" />
    <activity
        android:name=".ExperimentActivity"
        android:label="@string/category_experiment"
        android:theme="@style/category_experiment" />
</application>

试试setTitle本身，像这样:

setTitle("Hello StackOverflow");

有个更快的方法，用

YourActivity.setTitle("New Title");

你也可以在onCreate()中找到它，例如:

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        this.setTitle("My Title");
    }

顺便说一下，您根本不能在不传递任何Activity对象的情况下以静态方式调用setTitle()。

这对我很管用。

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.fragment, container, false);
    getActivity().setTitle("My Title");
//...
}