小编Kan*_*ngh的帖子

与androidx我一起构建Gradle时，出现以下错误。请帮我解决这个问题。

错误消息：清单合并失败：来自[com.android.support:support-compat:28.0.0]的属性application @ appComponentFactory value =（android.support.v4.app.CoreComponentFactory）是AndroidManifest.xml：22：18-91也出现在[androidx.core：core：1.0.0] AndroidManifest.xml：22：18-86 value =（androidx.core.app.CoreComponentFactory）。

表现：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.kanwarpreet.dealmybook">

    <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=".activities.SplashActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".activities.LoginActivity" />
        <activity android:name=".activities.RegisterActivity" />
        <activity
            android:name=".activities.HomeActivity"
            android:label="@string/title_activity_home"
            android:theme="@style/AppTheme.NoActionBar" />
        <activity
            android:name=".activities.BookDetailsActivity"
            android:label="@string/title_activity_book_details"
            android:theme="@style/AppTheme.NoActionBar"/>
        <activity android:name=".activities.AddBookActivity" />
    </application>

</manifest>

Build.Gradle：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.kanwarpreet.dealmybook"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" …

我正在开发一个将图像上传到Amazon S3 存储桶的应用程序，我希望能够获取有关上传状态的进度，而不是仅仅显示 Spinner 。

  static Future<bool> uploadFile({@required userId, @required albumId, @required data, @required fileName}) async{

    const _accessKeyId = 'AKIAVV**********';
    const _secretKeyId = 'iyBmdn6v***************************';
    const _region = 'us-east-1';
    const _s3Endpoint = 'https://myalbums-content.s3.amazonaws.com';

    final file = data;
    var stream = new http.ByteStream(DelegatingStream.typed(file.openRead()));
    final length = await file.length();

    final uri = Uri.parse(_s3Endpoint);
    final req = http.MultipartRequest("POST", uri);

    var multipartFile =  http.MultipartFile('file', stream, length,
       contentType: new MediaType('image','JPG'));

    final policy = Policy.fromS3PresignedPost(userId.toString() +'/'+ albumId.toString() …