如何解决“错误：包 android.support.v7.widget 不存在”的问题？

Question

I want to add an Action Bar to my app. And there is a problem appearing

error: package android.support.v7.widget does not exist .

I cannot fix that problem whatever i tried. Any solution on internet does not work on me.I do not know why this is happening and i am really tired of it. I am the beginner and this problem drives me crazy.I've tried to change

android.useAndroidX=true --> to false

and

android.enableJetifier=true --> false on gradle.properties

Yeah, its work!But here is another problem appearing:

java.lang.RuntimeException: Manifest merger failed : Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml:22:18-91

Here is my build.gradle:

    compileSdkVersion 29
    buildToolsVersion '29.0.1'
    minSdkVersion 21
    targetSdkVersion 29


dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0-rc01'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta2'
    implementation 'com.google.android.material:material:1.1.0-alpha07'
    testİmplementation 'junit:junit:4.13-beta-3'
    androidTestİmplementation 'androidx.test:runner:1.3.0-alpha01'
    androidTestİmplementation 'androidx.test.espresso:espresso-core:3.3.0-alpha01'
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:support-v4:28.0.0'
    implementation 'com.android.support:support-v13:28.0.0'

}

Could be problem on implementation methods, i do not know. May be i have a problem on SDK versions. I have tried migrate to AndroidX and not worked.

Answer 1

Please try this:

implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'androidx.appcompat:appcompat:1.0.2'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'com.google.android.material:material:1.0.0'
implementation 'androidx.vectordrawable:vectordrawable:1.0.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test:runner:1.1.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'

Answer 2

Try replacing

android.support.v7.widget

with

androidx.appcompat.widget

Answer 3

Welcome to stackoverflow!

You have both support library and androidx library in one project...that's your issue...

Change the support libraries to the preferred AndroidX library...

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0-rc01'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta2'
    implementation 'com.google.android.material:material:1.1.0-alpha07'
    testİmplementation 'junit:junit:4.13-beta-3'
    androidTestİmplementation 'androidx.test:runner:1.3.0-alpha01'
    androidTestİmplementation 'androidx.test.espresso:espresso-core:3.3.0-alpha01'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'androidx.legacy:legacy-support-v13:1.0.0'

}

Or you can probably Migrate to AndroidX and it can be done right in Android Studio

Simply go to Refactor > Migrate to AndroidX > Migrate

Adding an Action Bar

<androidx.appcompat.widget.Toolbar
   android:id="@+id/toolbar"
   android:layout_width="match_parent"
   android:layout_height="?attr/actionBarSize"
   android:background="@color/yourColor"/>

I hope this helps....

Answer 4

Your project is missing the support library from the SDK.

If you have not installed them, just right click on the project > Android Tools > Install support library .

Then, just import into workspace, as an Android project, android-support-v7-appcompat , located into ${android-sdk-path}/extras/android/support/v7

And finally, right click in the Android project > Properties > Android Tab . Push the Add button and add the support project "android-support-v7-appcompat" as dependency.

Clean your project and the must compile and work properly.

Answer 5

添加依赖项

implementation 'com.android.support:design:28.0.0'