Failed to load AppCompat ActionBar with unknown er

问题:

Below is my xml file. In preview there is two error\'Failed to load AppCompat ActionBar with unknown error\' & \'Failed to instaniate more than one class\'. How ever am able to run the app.But the app crashes and in Logcat no errors are shown.

This is my preview screen shot

<?xml version=\"1.0\" encoding=\"utf-8\"?>
<android.support.v4.widget.DrawerLayout 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:id=\"@+id/drawer_layout\"
    android:layout_width=\"match_parent\"
    android:layout_height=\"match_parent\"
    android:fitsSystemWindows=\"true\"
    tools:openDrawer=\"start\">


    <include
        layout=\"@layout/app_bar_main\"
        android:layout_width=\"match_parent\"
        android:layout_height=\"506dp\" />

    <LinearLayout
        android:id=\"@+id/layout_main\"
        android:orientation=\"vertical\"
        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:weightSum=\"1\"
        tools:context=\".Activity.MainActivity\">


    <LinearLayout
        android:id=\"@+id/main_layout\"
        android:orientation=\"vertical\"
        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:layout_weight=\"0.7\"
        tools:context=\".Activity.MainActivity\">

        <!-- our tablayout to display tabs  -->
        <android.support.design.widget.TabLayout
            android:id=\"@+id/tabLayout\"
            android:layout_width=\"match_parent\"
            android:layout_height=\"wrap_content\"
            android:layout_marginTop=\"50dp\"
            app:tabMode=\"scrollable\"
            app:tabSelectedTextColor=\"@color/colorBlack\"
            app:tabTextColor=\"@color/colorWhite\"
            android:background=\"@color/colorOran\"
            android:minHeight=\"?attr/actionBarSize\"
            />

        <!-- View pager to swipe views -->
        <android.support.v4.view.ViewPager
            android:id=\"@+id/pager\"
            android:layout_width=\"match_parent\"
            android:layout_height=\"match_parent\"/>

    </LinearLayout>

        <LinearLayout
            android:id=\"@+id/ll\"
            android:layout_width=\"match_parent\"
            android:layout_height=\"64dp\"
            android:layout_alignParentBottom=\"true\"
            android:background=\"#ffffff\"
            android:orientation=\"horizontal\"
            android:layout_weight=\"0.3\"
            android:weightSum=\"4\"
            tools:layout_editor_absoluteX=\"8dp\"
            android:layout_marginBottom=\"8dp\"
            android:layout_alignParentLeft=\"true\"
            android:layout_alignParentStart=\"true\">

            <ImageView
                android:id=\"@+id/btn_home\"
                android:layout_width=\"wrap_content\"
                android:layout_height=\"match_parent\"
                android:layout_weight=\"1\"
                android:src=\"@drawable/ta_home_icon\"
                android:background=\"@color/colorOran\"
                android:layout_marginRight=\"1dp\"
                android:scaleType=\"fitCenter\"/>

            <ImageView
                android:id=\"@+id/btn_new\"
                android:layout_width=\"wrap_content\"
                android:layout_height=\"match_parent\"
                android:layout_weight=\"1\"
                android:src=\"@drawable/ta_todaydeals_icon\"
                android:background=\"@color/colorOran\"
                android:layout_marginRight=\"1dp\"
                android:scaleType=\"fitCenter\"/>

            <ImageView
                android:id=\"@+id/btn_fav\"
                android:layout_width=\"wrap_content\"
                android:layout_height=\"match_parent\"
                android:layout_weight=\"1\"
                android:src=\"@drawable/ta_fav_icon\"
                android:background=\"@color/colorOran\"
                android:layout_marginRight=\"1dp\"
                android:scaleType=\"fitCenter\"/>

            <ImageView
                android:id=\"@+id/btn_auth\"
                android:layout_width=\"wrap_content\"
                android:layout_height=\"match_parent\"
                android:layout_weight=\"1\"
                android:src=\"@drawable/ta_franchie_icon\"
                android:background=\"@color/colorOran\"
                android:scaleType=\"fitCenter\"
                android:layout_marginRight=\"1dp\"
                />

        </LinearLayout>

    </LinearLayout>


    <android.support.design.widget.NavigationView
        android:id=\"@+id/nav_view\"
        android:layout_width=\"wrap_content\"
        android:layout_height=\"match_parent\"
        android:layout_gravity=\"start\"
        android:fitsSystemWindows=\"true\"
        app:headerLayout=\"@layout/nav_header_main\"
        app:menu=\"@menu/activity_main_drawer\" />


</android.support.v4.widget.DrawerLayout>

Below is appbar_main

<?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.jeyashri.kitchen.jeyashriskitchen.Activity.MainActivity\">

    <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=\"@color/colorOran\"
            app:popupTheme=\"@style/AppTheme.PopupOverlay\">

            <ImageView
                android:id=\"@+id/app_logo\"
                android:layout_width=\"80dp\"
                android:layout_height=\"match_parent\"
                android:src=\"@drawable/img\"/>

            <ImageView
                android:id=\"@+id/btn_social\"
                android:layout_width=\"75dp\"
                android:layout_height=\"35dp\"
                android:layout_marginRight=\"1dp\"
                android:src=\"@drawable/share_icon\" />

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

    </android.support.design.widget.AppBarLayout>

    <include layout=\"@layout/content_main\" />


</android.support.design.widget.CoordinatorLayout>

回答1:

The solution to this problem depends on the version of the Android support library you\'re using:

Support library 26.0.0-beta2

This android support library version has a bug causing the mentioned problem

In your Gradle build file use:

compile \'com.android.support:appcompat-v7:26.0.0\'

with:

buildToolsVersion \'26.0.0\' 

and

classpath \'com.android.tools.build:gradle:3.0.0-alpha8\'

everything should work fine now.

---

Library version 28 (beta)

These new versions seem to suffer from similar difficulties again.

In your res/values/styles.xml modify the AppTheme style from

<style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.DarkActionBar\">

to

<style name=\"AppTheme\" parent=\"Base.Theme.AppCompat.Light.DarkActionBar\">

(note the added Base.)

Or alternatively downgrade the library until the problem is fixed:

implementation \'com.android.support:appcompat-v7:28.0.0-alpha1\'

回答2:

found it on this site, it works on me. Modify /res/values/styles.xml from:

<style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.DarkActionBar\">
</style>

to:

<style name=\"AppTheme\" parent=\"Base.Theme.AppCompat.Light.DarkActionBar\">
</style>

回答3:

June 2018 Issue fixed by using a different appcompact version. Use these codes onto your project dependencies...

In build.gradle(Module: app) add this dependency

implementation \'com.android.support:appcompat-v7:28.0.0-alpha1\'

Happy Coding... :)

回答4:

Method 1:

Locate /res/values/styles.xml

Change

<style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.DarkActionBar\">

To

<style name=\"AppTheme\" parent=\"Base.Theme.AppCompat.Light.DarkActionBar\">

Method 2:

Modify template file(locate: android-studio/plugins/android/lib/templates/gradle-projects/NewAndroidModule/root/res/values/styles.xml.ftl)

Change

backwardsCompatibility!true>Theme.AppCompat<#else><#if

To

backwardsCompatibility!true>Base.Theme.AppCompat<#else><#if

Watch Solution On YouTube

回答5:

I also had this problem and it\'s solved as change line from res/values/styles.xml

<style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.DarkActionBar\">

to

1. <style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.NoActionBar\">
2. <style name=\"AppTheme\" parent=\"Base.Theme.AppCompat.Light.DarkActionBar\">

both solutions worked

回答6:

Open preview mode

follow the below link to fix the issue

Fix - Rendering Problems The Following classes could not be found : android.support.v7.internal

goto appTheme ----> select Holo Theme ---> refresh

https://www.youtube.com/watch?v=4MxBnwpcUjA

回答7:

Replace implementation \'com.android.support:appcompat-v7:28.0.0-beta01\' with

implementation \'com.android.support:appcompat-v7:28.0.0-alpha1\' 

in build.gradle (Module:app). It fixed my red mark in Android Studio 3.1.3

回答8:

in android 3.0.0 canary 6 you must change all 2.6.0 beta2 to beta1 (appcompat,design,supportvector)

回答9:

Try this:

Just change:

compile \'com.android.support:appcompat-v7:26.0.0-beta2\'

to:

compile \'com.android.support:appcompat-v7:26.0.0-beta1\'

Reference

回答10:

This is Worked for me i have made the following changes in Style.xml

Change the Following Code:

<style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.DarkActionBar\">

With

<style name=\"AppTheme\" parent=\"Base.Theme.AppCompat.Light.DarkActionBar\">

回答11:

Use this one:

implementation \'com.android.support:appcompat-v7:26.0.0-beta1\'
implementation \'com.android.support:design:26.0.0-beta1\'

instead of

implementation \'com.android.support:appcompat-v7:26.0.0-beta2\'
implementation \'com.android.support:design:26.0.0-beta2\'

In my case it removed the rendering problem.

回答12:

This is the minimum configuration that solves the problem.

use:

dependencies {
    ...
    implementation \'com.android.support:appcompat-v7:26.1.0\'
    ...
}

with:

 compileSdkVersion 26
 buildToolsVersion \"26.0.1\"

and into the build.gradle file located inside the root of the proyect:

buildscript {
    ...
    ....
    dependencies {
        classpath \'com.android.tools.build:gradle:3.0.1\'
        ...
        ...
    }
}

回答13:

I was also facing the same problem. Nothing like changing theme from Layout preview window helped me.

What helped me was adding this to Apptheme in styles.xml:

dependencies {
    implementation \'com.android.support:appcompat-v7:27.0.2\'
    implementation \'com.android.support:design:27.0.2\'
}

Still it was giving me the error: \"cannot resolve symbol widget...coordinatorLayout\". Then I updated my build.gradle(app) with:

dependencies {
    implementation \'com.android.support:appcompat-v7:27.0.2\'
    implementation \'com.android.support:design:27.0.2\'
}

One more thing:

compileSdkVersion 27
targetSdkVersion 27

回答14:

I also had this problem with implementation \'com.android.support:appcompat-v7:28.0.0-alpha3\'.

The solution for me was to go File -> Invalidate Caches / Restart -> Invalidate -> Close Project -> Remove project from project window -> Open Project (from project window).

回答15:

Faced the same problem in Android Studio 3.1.3

Just go to style.xml file

and replace Theme name

<style name=\"AppTheme\" parent=\"Theme.AppCompat.Light.DarkActionBar\">

with

<style name=\"AppTheme\" parent=\"Base.Theme.AppCompat.Light.DarkActionBar\">

Then clean and rebuild the project.This will solve the error.