Android 工作室操作栏未在新 activity 中显示
Android studio action bar not showing in new activity
style.xml
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
<style name="AppTheme.NoActionBar">
<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>
</style>
<style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />
<style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />
</resources>
在我的新活动中，我的操作栏不会显示，我不确定为什么会这样。它只出现在第一个 activity 上。并且它没有出现在任何其他活动中。我是 android 开发的新手，所以这可能是个新问题。但它真的困扰着我。我已经包含了我的项目代码。感谢阅读！
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.karanvir.search.MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<AutoCompleteTextView
android:id="@+id/autoCompleteTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="59dp"
android:text="AutoCompleteTextView" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/autoCompleteTextView"
android:layout_marginLeft="12dp"
android:layout_marginStart="12dp"
android:layout_marginTop="48dp"
android:layout_toEndOf="@+id/progressBar"
android:layout_toRightOf="@+id/progressBar"
android:onClick="jump"
android:text="Button" />
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true" />
</RelativeLayout>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>
package com.karanvir.search;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import static com.karanvir.search.MainActivity.urlGlobal;
public class Main2Activity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//finding webview
WebView webView=(WebView) findViewById(R.id.web1);
//whole bunch of settings you might want to do if you .
//do this because javascript is so wildely used that if you dont use this anywebsites you display wont be displayed properly
webView.getSettings().setJavaScriptEnabled(true);
//this is because on a number of phones if you dont do this it will jump to the devices default browser, and ddisplay the websview their instead.
webView.setWebViewClient(new WebViewClient());
webView.loadUrl("https://www.google.ca/?gws_rd=ssl#q="+urlGlobal);
//reminder ask permission
//you can load content using loaddata
//then add type of data
//then add character encoded were using
}
}
package com.karanvir.search;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Intent intentGoogle;
Random rn;
SharedPreferences urls;
AutoCompleteTextView searchBar;
public static String urlGlobal;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
searchBar=(AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
Button button=(Button) findViewById(R.id.button);
rn= new Random();
urls=this.getSharedPreferences("com.karanvir.search", Context.MODE_PRIVATE);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings4) {
Intent intentGoogle= new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intentGoogle);
return true;
} else if(id ==R.id.action_settings2){
Intent intentGoogle= new Intent(getApplicationContext(),Yahoo.class);
startActivity(intentGoogle);
return true;
}else if (id==R.id.action_settings3){
Intent intentGoogle= new Intent(getApplicationContext(),MainActivity.class);
startActivity(intentGoogle);
return true;
}else if(id==R.id.action_settings1){
new AlertDialog.Builder(this)
.setIcon(android.R.drawable.alert_dark_frame)
.setTitle("About")
.setMessage("stuff");
return true;
}
return super.onOptionsItemSelected(item);
}
public void jump(View view){
//intnet changing target of our code
urlGlobal=searchBar.getText().toString();
Log.i("stuff",urlGlobal);
//public static String urlGlobal=
/* urls.edit().putString("url",searchBar.getText().toString()).apply();
String Stringurls=urls.getString("url","");*/
int pageJump = rn.nextInt(3)+1;
if (pageJump==1){
//google
Intent intentGoogle= new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intentGoogle);
} else if (pageJump==2){
//YAHOO
Intent intentGoogle= new Intent(getApplicationContext(),Yahoo.class);
startActivity(intentGoogle);
} else if(pageJump==3){
//GOOGLE
Intent intentGoogle= new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intentGoogle);
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.karanvir.search">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Main2Activity"
android:label="@string/title_activity_main2"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Yahoo"
android:label="@string/title_activity_yahoo"
android:theme="@style/AppTheme.NoActionBar"></activity>
</application>
</manifest>
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.karanvir.search.Main2Activity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/web1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true" />
</RelativeLayout>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>
将此添加到您的 styles.xml
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/grey_400</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
And in your Manifest add this in every Activity
<activity
android:name=".YourActivity"
android:label="@string/title_activity_main2"
android:theme="@style/AppTheme" />
在 style.xml
中尝试上面的方法
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
并像上面那样更新您的 AndroidManifest 文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.karanvir.search">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
>
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Main2Activity"
android:label="@string/title_activity_main2"
/>
<activity
android:name=".Yahoo"
android:label="@string/title_activity_yahoo"
></activity>
</application>
尝试将 activity 主题设置为 AppTheme.NoActionBar，希望对您有所帮助。
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<LinearLayout
android:id="@+id/activity_login"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="@style/AppTheme.PopupOverlay">
<TextView
style="@style/Base.TextAppearance.Widget.AppCompat.Toolbar.Title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/login_title"
android:textColor="@color/colorPrimary"
/>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
当您使用 Android Studio 并添加新的 Activity 尝试：
File -> New -> Activity -> Basic Activity
那么它默认配置了ActionBar。
style.xml
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
<style name="AppTheme.NoActionBar">
<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>
</style>
<style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />
<style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />
</resources>
在我的新活动中，我的操作栏不会显示，我不确定为什么会这样。它只出现在第一个 activity 上。并且它没有出现在任何其他活动中。我是 android 开发的新手，所以这可能是个新问题。但它真的困扰着我。我已经包含了我的项目代码。感谢阅读！
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.karanvir.search.MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<AutoCompleteTextView
android:id="@+id/autoCompleteTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="59dp"
android:text="AutoCompleteTextView" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/autoCompleteTextView"
android:layout_marginLeft="12dp"
android:layout_marginStart="12dp"
android:layout_marginTop="48dp"
android:layout_toEndOf="@+id/progressBar"
android:layout_toRightOf="@+id/progressBar"
android:onClick="jump"
android:text="Button" />
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true" />
</RelativeLayout>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>
package com.karanvir.search;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import static com.karanvir.search.MainActivity.urlGlobal;
public class Main2Activity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//finding webview
WebView webView=(WebView) findViewById(R.id.web1);
//whole bunch of settings you might want to do if you .
//do this because javascript is so wildely used that if you dont use this anywebsites you display wont be displayed properly
webView.getSettings().setJavaScriptEnabled(true);
//this is because on a number of phones if you dont do this it will jump to the devices default browser, and ddisplay the websview their instead.
webView.setWebViewClient(new WebViewClient());
webView.loadUrl("https://www.google.ca/?gws_rd=ssl#q="+urlGlobal);
//reminder ask permission
//you can load content using loaddata
//then add type of data
//then add character encoded were using
}
}
package com.karanvir.search;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Intent intentGoogle;
Random rn;
SharedPreferences urls;
AutoCompleteTextView searchBar;
public static String urlGlobal;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
searchBar=(AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
Button button=(Button) findViewById(R.id.button);
rn= new Random();
urls=this.getSharedPreferences("com.karanvir.search", Context.MODE_PRIVATE);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings4) {
Intent intentGoogle= new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intentGoogle);
return true;
} else if(id ==R.id.action_settings2){
Intent intentGoogle= new Intent(getApplicationContext(),Yahoo.class);
startActivity(intentGoogle);
return true;
}else if (id==R.id.action_settings3){
Intent intentGoogle= new Intent(getApplicationContext(),MainActivity.class);
startActivity(intentGoogle);
return true;
}else if(id==R.id.action_settings1){
new AlertDialog.Builder(this)
.setIcon(android.R.drawable.alert_dark_frame)
.setTitle("About")
.setMessage("stuff");
return true;
}
return super.onOptionsItemSelected(item);
}
public void jump(View view){
//intnet changing target of our code
urlGlobal=searchBar.getText().toString();
Log.i("stuff",urlGlobal);
//public static String urlGlobal=
/* urls.edit().putString("url",searchBar.getText().toString()).apply();
String Stringurls=urls.getString("url","");*/
int pageJump = rn.nextInt(3)+1;
if (pageJump==1){
//google
Intent intentGoogle= new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intentGoogle);
} else if (pageJump==2){
//YAHOO
Intent intentGoogle= new Intent(getApplicationContext(),Yahoo.class);
startActivity(intentGoogle);
} else if(pageJump==3){
//GOOGLE
Intent intentGoogle= new Intent(getApplicationContext(),Main2Activity.class);
startActivity(intentGoogle);
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.karanvir.search">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Main2Activity"
android:label="@string/title_activity_main2"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Yahoo"
android:label="@string/title_activity_yahoo"
android:theme="@style/AppTheme.NoActionBar"></activity>
</application>
</manifest>
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.karanvir.search.Main2Activity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/web1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true" />
</RelativeLayout>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>
将此添加到您的 styles.xml
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/grey_400</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
And in your Manifest add this in every Activity
<activity
android:name=".YourActivity"
android:label="@string/title_activity_main2"
android:theme="@style/AppTheme" />
在 style.xml
中尝试上面的方法<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
并像上面那样更新您的 AndroidManifest 文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.karanvir.search">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
>
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Main2Activity"
android:label="@string/title_activity_main2"
/>
<activity
android:name=".Yahoo"
android:label="@string/title_activity_yahoo"
></activity>
</application>
尝试将 activity 主题设置为 AppTheme.NoActionBar，希望对您有所帮助。
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<LinearLayout
android:id="@+id/activity_login"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="@style/AppTheme.PopupOverlay">
<TextView
style="@style/Base.TextAppearance.Widget.AppCompat.Toolbar.Title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/login_title"
android:textColor="@color/colorPrimary"
/>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
当您使用 Android Studio 并添加新的 Activity 尝试：
File -> New -> Activity -> Basic Activity
那么它默认配置了ActionBar。