小编Dan*_*ele的帖子

一个非常基本的问题,在Kotlin中连接String的正确方法是什么？

在Java中,您将使用该concat()方法,例如

String a = "Hello ";
String b = a.concat("World"); // b = Hello World

但该concat()功能不适用于Kotlin.我应该使用这个+标志吗？

是否有可能将谷歌助手集成到Android应用程序中？

我在网上找不到任何关于它的信息.

我知道今天谷歌发布了助手SDK,但即使在他们的Android开发者博客帖子中他们也没有提到任何Android支持

如果安装了应用程序可以提供的内容,这将是有用的.

例如:

"好的谷歌,在亚马逊上找到星球大战蓝光"

它将启动亚马逊购物应用程序并寻找它.

是否可以使用此发布的SDK在应用程序中实现类似的功能？

Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Cache
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Call
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't …

在Kotlin中,我将覆盖这两个Google登录功能:

override fun onConnectionFailed(result: ConnectionResult) {
        if (result.hasResolution()) {
            try {
                result.startResolutionForResult(this, RESOLVE_CONNECTION_REQUEST_CODE)
            } catch (e: IntentSender.SendIntentException) {
                // Unable to resolve, message user appropriately
            }

        } else {
            val gaa = GoogleApiAvailability.getInstance()
            gaa.getErrorDialog(this, result.errorCode, 0)
        }
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent) {
        when (requestCode) {
            RESOLVE_CONNECTION_REQUEST_CODE -> if (resultCode == Activity.RESULT_OK) {
                mGoogleApiClient!!.connect()
            }
        }
    }

检查与谷歌的连接是否失败.

问题是,有时,当我关闭包含用户帐户的对话框时,会在启动活动时弹出该对话框

像这个:

我正在IllegalArgumentException使用以下logcat

E/AndroidRuntime:FATAL EXCEPTION:main进程:com.dancam.subscriptions,PID:6346 java.lang.RuntimeException:将结果ResultInfo {who = null,request = 6783,result = 0,data = null}传递给activity {失败.dancam.subscriptions/com.dancam.subscriptions.ActiveSubscriptions.Subscriptions_main}:java.lang.IllegalArgumentException:指定为非null的参数为null:方法kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull,android.app.ActivityThread中的参数数据.deliverResults(ActivityThread.java:4126)在android.app.ActivityThread.handleSendResult(ActivityThread.java:4169)的android.app.ActivityThread.-wrap20(ActivityThread.java)android.app.ActivityThread …

渲染问题无法解析资源@id/search_edit_frame

这是我在xml文件中得到的渲染错误.我认为它与我的support.v7.SearchView下面有关系是我的xml:

 <RelativeLayout
    android:id="@+id/layout_ricerca"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="@drawable/search_border_backgroud"
    android:layout_marginStart="10dp"
    android:layout_marginEnd="10dp"
    android:layout_marginTop="20dp">

    <android.support.v7.widget.SearchView
        android:id="@+id/testo_ricerca"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:queryHint="@string/search_hint"
        android:textSize="25sp"
        android:layout_marginStart="5dp"
        android:iconifiedByDefault="false"/>

    <ImageButton
        android:id="@+id/tasto_ricerca"
        android:background="@color/trans"
        android:layout_marginTop="2dp"
        android:layout_width="45dp"
        android:layout_height="match_parent"
        android:layout_marginEnd="3dp"
        android:scaleType="centerInside"
        android:layout_alignParentEnd="true"
        android:src="@drawable/tasto_ricerca"/>
</RelativeLayout>

当我改变了<android.support.v7.widget.SearchView对<SearchView错误消失,但是这不是一个很好的解决方案适合我,因为我不得不改变我所有的Java代码与合作SearchView,而不是android.support.v7.widget.SearchView.

有谁知道如何解决这个问题？为什么会这样？我不认为我的xml有什么问题.

编辑:

添加了错误的屏幕截图

我为我的RecyclerView设置了一个ItemClickLister,如下所示:

ItemClickSupport.addTo(recyclerView!!).setOnItemClickListener(
                    object : ItemClickSupport.OnItemClickListener {
                        override fun onItemClicked(recyclerView: RecyclerView?, position: Int, v: View?) {
                            val row = recyclerView!!.getChildAt(position)
                            val el = row.findViewById(R.id.active_expandablelayout) as ExpandableLayout

                            if (el.isExpanded) {
                                el.collapse()
                            } else {
                                el.expand()
                            }
                        }
                    }
            )

使用我翻译成Kotlin的ItemClickSupport库.

我在object(第2行)上收到错误消息:

object必须声明为abstract或实现抽象成员.

我是Kotlin的新手,我也找不到任何解决方案.

任何帮助是极大的赞赏.

编辑:

这是我的ItemClickSupport.kt:

class ItemClickSupport private constructor(private val mRecyclerView: RecyclerView) {
    private var mOnItemClickListener: OnItemClickListener? = null
    private var mOnItemLongClickListener: OnItemLongClickListener? = null
    private val mOnClickListener = View.OnClickListener { v ->
        if (mOnItemClickListener != null) …

我一直在nougat上开发一个应用程序,它在外部存储中创建一个目录.

我过去常常这样做:

final File dir = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Chords/Processed Audio");
dir.mkdirs();

此代码似乎不适用于API 26(Android Oreo).目录未创建.

我怎样才能实现相同的功能,最好适用于从API 21到API 26的所有Android版本？

尝试在发布模式下构建应用程序时遇到此错误。

错误：属性签名需要InnerClasses属性。检查-keepattributes指令

我的proguard-rules.pro行看起来像这样：

-keepattributes Signature

编译器指的是什么InnerClasses？我要省略什么？

For my App I need to have a List sync with Google Drive. I have already implemented the SignIn and had my Main_Activity implement both:

com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks,
com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener

Even though I read the whole Google Drive API for Android documentation, and more specifically the Store Application Data part. And looked through the example on GitHub, I wasn't able to get it to work. I personally think that this documentation is really confusing to read. It's not even clear what is …

我需要画这样的东西：

我尝试通过创建 aCustomClipper<Path>并在 a 中使用它来做到这一点ClipPath()

这是我的代码：

class ArcBackground extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ClipPath(
      child: Container(
        width: double.infinity,
        height: 400.0,
        color: Colors.orange,
      ),
      clipper: RoundedClipper(),
    );
  }
}

class RoundedClipper extends CustomClipper<Path> {
  @override
  Path getClip(Size size) {
    var path = Path();
    path.lineTo(0.0, size.height);
    path.quadraticBezierTo(
      size.width / 2, 
      size.height - 100, 
      size.width, 
      size.height
    );
    path.lineTo(size.width, 0.0);
    path.close();
    return path;
  }

  @override
  bool shouldReclip(CustomClipper<Path> oldClipper) => false;
}

这段代码给了我以下输出：

正如您所看到的，弧指向上是因为我将quadraticaBezierTo() y1属性设置为size.height …