我想在我的应用程序中添加一个工具栏而不是操作栏。但是，当我将工具栏添加到我的应用程序时，我的应用程序崩溃了，我不知道怎么办。

这是我的代码。

ToolbarActivity.java

public class ToolbarActivity extends AppCompatActivity{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_toolbar);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbarsdfs);
        if (toolbar != null) {
            setSupportActionBar(toolbar);
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        }
    }
}

activity_toolbar.xml

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbarsdfs"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:background="?attr/colorPrimary" />

</LinearLayout>

style.xml

<style name="AppTheme" parent="AppTheme.Base"/>

    <style name="AppTheme.Base" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="colorPrimary">@color/color1</item>
        <item name="colorPrimaryDark">@color/color2</item>
        <item name="android:windowNoTitle">true</item>
        <item name="windowActionBar">false</item>
    </style>

LogCat

08-12 14:31:05.905: E/AndroidRuntime(18413): FATAL EXCEPTION: main
08-12 14:31:05.905: E/AndroidRuntime(18413): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tech.Toolbar/com.tech.toolbar.ToolbarActivity}: java.lang.NullPointerException
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1734)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.ActivityThread.startActivityNow(ActivityThread.java:1569)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:158)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:370)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:701)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.widget.TabHost.setCurrentTab(TabHost.java:373)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.widget.TabHost$2.onTabSelectionChanged(TabHost.java:167)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.widget.TabWidget$TabClickListener.onClick(TabWidget.java:487)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.view.View.performClick(View.java:2535)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.view.View$PerformClick.run(View.java:9129)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.os.Handler.handleCallback(Handler.java:618)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.os.Handler.dispatchMessage(Handler.java:123)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.os.Looper.loop(SourceFile:351)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.ActivityThread.main(ActivityThread.java:3820)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at java.lang.reflect.Method.invokeNative(Native Method)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at java.lang.reflect.Method.invoke(Method.java:538)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:969)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:727)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at dalvik.system.NativeStart.main(Native Method)
08-12 14:31:05.905: E/AndroidRuntime(18413): Caused by: java.lang.NullPointerException
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.support.v7.internal.app.WindowDecorActionBar.getDecorToolbar(WindowDecorActionBar.java:248)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.support.v7.internal.app.WindowDecorActionBar.init(WindowDecorActionBar.java:201)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.support.v7.internal.app.WindowDecorActionBar.<init>(WindowDecorActionBar.java:176)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.support.v7.app.AppCompatDelegateImplV7.createSupportActionBar(AppCompatDelegateImplV7.java:174)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.support.v7.app.AppCompatDelegateImplBase.getSupportActionBar(AppCompatDelegateImplBase.java:90)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.support.v7.app.AppCompatActivity.getSupportActionBar(AppCompatActivity.java:77)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at com.tech.toolbar.ToolBarActivity.onCreate(ToolBarctivity.java:12)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1082)
08-12 14:31:05.905: E/AndroidRuntime(18413):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1698)
08-12 14:31:05.905: E/AndroidRuntime(18413):    ... 18 more
08-12 14:31:05.920: E/dalvikvm(18413): [DVM] mmap return base = 45e92000

list

<uses-sdk
        android:minSdkVersion="10" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/CustomActionBarTheme"
         >
<activity
            android:name=".MainActivity"
            android:label="Tab"
            android:noHistory="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

<activity 
           android:name=".ToolBarActivity"
           android:theme="@style/AppTheme" />            

            </application>

我已经尽一切可能实现我的目标，但无济于事。我的应用程序最小 SDK 是 10。我正在使用 eclipse Luna 进行开发。

最佳答案

您正在尝试查找 NULL 的 View 。

您的代码:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

你的 xml:

android:id="@+id/toolbarsdfs"

错误!!

如果您试图找到您的 Toolbar，您必须正确输入您的 Toolbar 的 ID!!

Toolbar 的代码应该是:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbarsdfs);

顺便说一句，将“类扩展”更改为:

public class ToolbarActivity extends AppCompatActivity

希望它有用:)

编辑

好的。我创建了一个样本，如果我误解了你的话，请告诉我，我会告诉你我做了什么。

样式.xml

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">#f0f0</item>
    <item name="colorPrimaryDark">#f3f</item>
    <item name="windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
</style>

主 Activity .java

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbarsdfs);
    if (toolbar != null) {
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<android.support.v7.widget.Toolbar
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbarsdfs"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:background="?attr/colorPrimaryDark"
    app:theme="@style/ThemeOverlay.AppCompat.ActionBar">

</android.support.v7.widget.Toolbar>

这是结果:

这是你想要的吗？

关于android - 添加工具栏出错，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31961029/