错误：包 android.support.design.widget 不存在 import android.support.design.widget.FloatingActionButton;

Question

I am new to android. I was trying to run code. I get the following error.

error: package android.support.design.widget does not exist import android.support.design.widget.FloatingActionButton;

Please help to resolve it.

Here is the code myActivity.java -->

import android.support.design.widget.FloatingActionButton;
import android.support.v7.widget.Toolbar;

Here is the build.gradle--->

apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"

    defaultConfig {
        applicationId "com.education"
        minSdkVersion 19
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    useLibrary 'org.apache.http.legacy'

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

repositories {
    maven { url "https://jitpack.io" }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    testImplementation 'junit:junit:4.12'
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'com.google.android.material:material:1.1.0'
    implementation 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'
    implementation "com.google.android.gms:play-services-gcm:16.0.0"
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    implementation 'com.google.android.material:material:1.1.0-alpha04'
}

Answer 1

The problem is that you're using Androidx with Material Design Library and FloatingButton has been moved to Material UI. So, now you use it as

com.google.android.material.floatingactionbutton.FloatingActionButton

and not as android.support.design.widget.FloatingActionButton .

So change your code as :

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import androidx.appcompat.widget.Toolbar;

Also, this FloatingButton is a part of Material Design library now which you've mentioned two times in your build.gradle(app) file as :

implementation 'com.google.android.material:material:1.1.0'
...
implementation 'com.google.android.material:material:1.1.0-alpha04'

Remove first one as the second is more upto date.