试着这样做……

public void onCreate(Bundle savedInstanceState) 
{
super.onCreate(savedInstanceState);
    this.setTitle(String.format(your_format_string, your_personal_text_to_display));
    setContentView(R.layout.your_layout);
       ...
       ...
}

这对我很有用

你可以在Activity中使用setTitle以编程方式定义你的标题，这个方法可以接受在values/strings.xml文件中定义的String或ID。例子:

public class YourActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {

        setTitle(R.string.your_title);
        setContentView(R.layout.main);

    }
}

如果你正在使用导航栏来改变片段，那么你可以在你正在改变片段的地方添加更改，如下所示:

 public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.clientsidedrawer:
                    //    Toast.makeText(getApplicationContext(),"Client selected",Toast.LENGTH_SHORT).show();
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new clients_fragment()).commit();
                    break;
    
                case R.id.adddatasidedrawer:
                    getSupportActionBar().setTitle("Add Client");
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new addclient_fragment()).commit();
                    break;
    
                case R.id.editid:
                    getSupportActionBar().setTitle("Edit Clients");
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new Editclient()).commit();
                    break;
    
                case R.id.taskid:
                    getSupportActionBar().setTitle("Task manager");
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new Taskmanager()).commit();
                    break;

如果你正在使用简单的活动，那么只需调用:

getSupportActionBar().setTitle("Contact Us");

更改动作栏/工具栏的颜色使用:

getSupportActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#06023b")));

要将渐变设置为动作栏，首先创建渐变: 创建示例:> R.drawable.gradient_contactus

<?xml version="1.0" encoding="utf-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle"
    >

    <gradient
        android:angle="90"
        android:startColor="#2980b9"
        android:centerColor="#6dd5fa"
        android:endColor="#2980b9">
    </gradient>


</shape>

然后像这样设置:

getSupportActionBar().setBackgroundDrawable(getResources().getDrawable(R.drawable.gradient_contactus));

ActionBar ab = getActionBar();
TextView tv = new TextView(getApplicationContext());

LayoutParams lp = new RelativeLayout.LayoutParams(
        LayoutParams.MATCH_PARENT, // Width of TextView
        LayoutParams.WRAP_CONTENT);
tv.setLayoutParams(lp);
tv.setTextColor(Color.RED);
ab.setCustomView(tv);

欲了解更多信息，请查看此链接:

http://android--code.blogspot.in/2015/09/android-how-to-change-actionbar-title_21.html

您可以在清单文件中为每个活动定义标签。

一个活动的正常定义是这样的:

<activity
     android:name=".ui.myactivity"
     android:label="@string/Title Text" />

其中标题文本应替换为此活动的字符串资源的id。

如果希望动态地设置标题文本，也可以从代码中设置它。

setTitle(address.getCity());

在oncreate方法中，这一行将标题设置为活动的特定地址所在的城市。

我们可以用以下两种方式之一更改动作栏标题:

In the Manifest: in the manifest file, set the label of each Activity. android:label="@string/TitleWhichYouWantToDisplay" In code: in code, call the setTitle() method with a String or the id of String as the argument. public class MainActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { setTitle(R.string.TitleWhichYouWantToDisplay); // OR You can also use the line below // setTitle("MyTitle") setContentView(R.layout.activity_main); } }