android - 如何在 Android 中的 GridView 内的 imageView 上设置布局参数

Question

我是 android 的新手，我在 the official android site 上遇到了这个教程。关于如何创建图像的 GridView。我使用 kotlin 作为首选语言。在扩展 BaseAdapter 的适配器类中，我试图按照教程中的指示设置 ImageView 布局参数，但我收到一条错误消息，指出 GridView.LayoutParams 是未解析的引用。这是该类的完整代码:

class ImageAdapter(val context: Context) : BaseAdapter() {
    // references to our images
    val items: IntArray = intArrayOf(R.drawable.cat, R.drawable.daft_punk, R.drawable.gun, R.drawable.harvestors, R.drawable.intel, R.drawable.maserati, R.drawable.porsche, R.drawable.serveroom, R.drawable.spiderman, R.drawable.watch_dog)
    override fun getItem(p0: Int): Any {
        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
    }

    override fun getItemId(p0: Int): Long {
        return 0
    }

    override fun getCount(): Int {
        return items.size
    }

    // create a new ImageView for each item referenced by the Adapter
    override fun getView(p0: Int, p1: View?, p2: ViewGroup?): View {
        var imageView: ImageView
        if (p1 == null) {
      // if it's not recycled, initialize some attributes
            imageView= ImageView(context)
            imageView.layoutParams= GridView.LayoutParams(85,85)
            imageView.scaleType = ImageView.ScaleType.CENTER_CROP
            imageView.setPadding(8, 8, 8, 8)
        } else {
            imageView=p1 as ImageView
        }
        imageView.setImageResource(items[p0])
        return imageView
    }

}

错误出在 getView 方法中的 imageView.layoutParams=GridView.LayoutParams(85,85) 行。 LayoutParams 为红色，表示错误，当我将鼠标悬停在其上时，我收到消息:

Unresolved reference: LayoutParams

如何成功设置这些LayoutParams？因为没有它们，GridView 中的图像将以全高显示，我需要一个小图像，就像图库应用在我们的手机中显示它们一样。

后续问题:

当我将 imageView.layoutParams=GridView.LayoutParams(85,85) 替换为 imageView.layoutParams=AbsListView.LayoutParams(85,85) 时，我得到了一个javaOutOfMemory 错误。以下是完整的堆栈跟踪:

08-16 06:58:11.412 4543-4543/gallerie.classmite.com.imageviewer E/dalvikvm-heap: Out of memory on a 18662416-byte allocation.
08-16 06:58:11.431 4543-4543/gallerie.classmite.com.imageviewer E/AndroidRuntime: FATAL EXCEPTION: main

Process: gallerie.classmite.com.imageviewer, PID: 4543                                                                                  java.lang.OutOfMemoryError                                                                                                                                          
at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)                                                                                      
at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:609                                                                                      
at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:444)                                                                                     
at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:840)                                                                                     
at android.content.res.Resources.loadDrawable(Resources.java:2166)                                                                                     
at android.content.res.Resources.getDrawable(Resources.java:710)                                                                                      
at android.widget.ImageView.resolveUri(ImageView.java:638)                                                                                      
at android.widget.ImageView.setImageResource(ImageView.java:367)                                                                                     
at gallerie.classmite.com.imageviewer.ImageAdapter.getView(ImageAdapter.kt:32)                                                                                       
at android.widget.AbsListView.obtainView(AbsListView.java:2372)                                                                                      
at android.widget.GridView.makeAndAddView(GridView.java:1345)                                                                                      
at android.widget.GridView.makeRow(GridView.java:345)                                                                                     
at android.widget.GridView.fillDown(GridView.java:287)                                                                                      
at android.widget.GridView.fillFromTop(GridView.java:421)                                                                                      
at android.widget.GridView.layoutChildren(GridView.java:1233)                                                                                      
at android.widget.AbsListView.onLayout(AbsListView.java:2166)                                                                                      
at android.view.View.layout(View.java:15127)                                                                                      
at android.view.ViewGroup.layout(ViewGroup.java:4862)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1888)                                                                                      
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1742)                                                                                     
at android.widget.LinearLayout.onLayout(LinearLayout.java:1651)                                                                                     
at android.view.View.layout(View.java:15127)                                                                                      
at android.view.ViewGroup.layout(ViewGroup.java:4862)                                                                                     
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:515)                                                                                      
at android.widget.FrameLayout.onLayout(FrameLayout.java:450)                                                                                      
at android.view.View.layout(View.java:15127)                                                                                      
at android.view.ViewGroup.layout(ViewGroup.java:4862)                                                                                      
at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:374)                                                                                      
at android.view.View.layout(View.java:15127)                                                                                      
at android.view.ViewGroup.layout(ViewGroup.java:4862)                                                                                     
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:515)                                                                                      
at android.widget.FrameLayout.onLayout(FrameLayout.java:450)                                                                                     
at android.view.View.layout(View.java:15127)                                                                                     
at android.view.ViewGroup.layout(ViewGroup.java:4862)                                                                                     
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2315)                                                                                     
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2021)                                                                                     
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1189)                                                                                     
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6221)                                                                                     
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:788)                                                                                      
at android.view.Choreographer.doCallbacks(Choreographer.java:591)                                                                                     
at android.view.Choreographer.doFrame(Choreographer.java:560)                                                                                     
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:774)                                                                                     
at android.os.Handler.handleCallback(Handler.java:808)                                                                                      
at android.os.Handler.dispatchMessage(Handler.java:103)                                                                                      
at android.os.Looper.loop(Looper.java:193)                                                                                      
at android.app.ActivityThread.main(ActivityThread.java:5315)                                                                                      
at java.lang.reflect.Method.invokeNative(Native Method)                                                                                     
at java.lang.reflect.Method.invoke(Method.java:515)                                                                                   
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:829)                                                                                    
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:645)                                                                                     
at dalvik.system.NativeStart.main(Native Method)

仅当我在手机上运行该应用程序时出现此错误，但当我在模拟器中运行该应用程序时，在我进行上述替换后它可以正常运行。

Answer 1

你可以试试这个:

imageView.layoutParams = AbsListView.LayoutParams(85, 85)

AbsListView.LayoutParams 在 GridView 中用于检索 child 的 LayoutParams。

由于静态成员可以被子类继承in Java .当你调用GridView.LayoutParams时，它实际上是AbsListView.LayoutParams。但是，在 Kotlin 中，您不能以同样的方式进行。在子类之外，只能使用父类(super class)的名称来引用父类(super class)的伴生对象的成员。

后续问题的更新:

OutOfMemory 错误表示您正在将大图像加载到 ImageView。为了防止这种情况，您必须在显示之前缩小图像，引用这个 tutorial .你也可以使用一些图像加载框架，例如 Glide , 以显示您的图像。

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