GridView 中的项目不可见

Question

我正在使用 gridview 来显示一些 images.I 的代码，但我仍然没有得到任何图像

自定义适配器

public class CustomAdapter extends BaseAdapter {

    private Context context;
    private int[] images;

    public CustomAdapter(Context context, int[] images) {
        this.context = context;
        this.images = images;
    }

    @Override
    public int getCount() {
        return images.length;
    }

    @Override
    public Object getItem(int position) {
        return images[position];
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView = LayoutInflater.from(context).inflate(R.layout.custom_trips_frag_row, parent, false);
//            holder.tvHeader = (TextView) convertView.findViewById(R.id.tv_trips_home_header);
//            holder.tvDate = (TextView) convertView.findViewById(R.id.tv_trips_home_date);
            holder.ivImage = (ImageView) convertView.findViewById(R.id.iv_trips_home_image);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }

//        

        holder.ivImage.setImageResource(images[position]);


        return convertView;
    }


    private class ViewHolder {
        private TextView tvHeader;
        private TextView tvDate;
        private ImageView ivImage;
    }
}

主要Activity

public class MainActivity extends MasterActivity {
    private int[] images={R.drawable.images, R.drawable.images_2, R.drawable.images_1, R.drawable.images_4, R.drawable.images, R.drawable.images_2};
    private GridView gridView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.trips_frag);

        gridView = (GridView) findViewById(R.id.grid);
        gridView.setAdapter(new CustomAdapter(this, images));


    }
}

自定义行Xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <ImageView
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:id="@+id/iv_trips_home_image"
        android:src="@drawable/images"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <!--<TextView-->
        <!--android:layout_width="wrap_content"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:layout_below="@+id/iv_trips_home_image"-->
        <!--android:layout_centerHorizontal="true"-->
        <!--android:id="@+id/tv_trips_home_header" />-->

    <!--<triplogger.indiehustlers.com.triplogger.UTIL.CustomTextView-->
        <!--android:layout_width="wrap_content"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:id="@+id/tv_trips_home_header"-->
        <!--style="@style/textView"-->
        <!--android:text="Berlin"-->
        <!--android:textColor="#000"-->
        <!--android:textStyle="bold"-->
        <!--android:textSize="@dimen/header_text"-->
        <!--android:layout_below="@+id/iv_trips_home_image"-->
        <!--android:layout_centerHorizontal="true" />-->


    <!--<triplogger.indiehustlers.com.triplogger.UTIL.CustomTextView-->
        <!--android:layout_width="wrap_content"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:text="14-Sept-2014"-->
        <!--style="@style/textView"-->
        <!--android:visibility="gone"-->
        <!--android:textColor="#23170e17"-->
        <!--android:id="@+id/tv_trips_home_date"-->
        <!--android:layout_below="@+id/tv_trips_home_header"-->
        <!--android:layout_centerHorizontal="true" />-->
</RelativeLayout>

硕士Activity

public class MasterActivity extends Activity {
    protected Context activityContext;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        activityContext = getApplicationContext();
    }
}

trips_frag

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_marginRight="@dimen/margin_right"
    android:layout_marginLeft="@dimen/margin_left"

    android:layout_height="match_parent">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"

        android:orientation="horizontal">

        <ImageView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:src="@drawable/tab" />


        <ImageView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:src="@drawable/tab" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
       >

        <GridView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:numColumns="2"
            android:id="@+id/grid"
            android:verticalSpacing="5dp"
            android:stretchMode="spacingWidthUniform"></GridView>

    </LinearLayout>

</LinearLayout>

清单

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



    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/TripLoggerTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

我做了很多研究，但仍然没有取得任何成功我没弄明白哪里出错了？请帮帮我

Answer 1

从网格视图中删除 android:stretchMode="spacingWidthUniform"。您已经在项目布局中修复图像视图 griditem 的高度宽度

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <GridView
        android:id="@+id/griddata"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:numColumns="2"
        android:stretchMode="spacingWidthUniform"
        android:verticalSpacing="5dp" >
    </GridView>

</LinearLayout>

GridItemLayout

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/iv_trips_home_image"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <!-- <TextView -->
    <!-- android:layout_width="wrap_content" -->
    <!-- android:layout_height="wrap_content" -->
    <!-- android:layout_below="@+id/iv_trips_home_image" -->
    <!-- android:layout_centerHorizontal="true" -->
    <!-- android:id="@+id/tv_trips_home_header" /> -->


    <!-- <triplogger.indiehustlers.com.triplogger.UTIL.CustomTextView -->
    <!-- android:layout_width="wrap_content" -->
    <!-- android:layout_height="wrap_content" -->
    <!-- android:id="@+id/tv_trips_home_header" -->
    <!-- style="@style/textView" -->
    <!-- android:text="Berlin" -->
    <!-- android:textColor="#000" -->
    <!-- android:textStyle="bold" -->
    <!-- android:textSize="@dimen/header_text" -->
    <!-- android:layout_below="@+id/iv_trips_home_image" -->
    <!-- android:layout_centerHorizontal="true" /> -->


    <!-- <triplogger.indiehustlers.com.triplogger.UTIL.CustomTextView -->
    <!-- android:layout_width="wrap_content" -->
    <!-- android:layout_height="wrap_content" -->
    <!-- android:text="14-Sept-2014" -->
    <!-- style="@style/textView" -->
    <!-- android:visibility="gone" -->
    <!-- android:textColor="#23170e17" -->
    <!-- android:id="@+id/tv_trips_home_date" -->
    <!-- android:layout_below="@+id/tv_trips_home_header" -->
    <!-- android:layout_centerHorizontal="true" /> -->

</RelativeLayout>

Answer 2

从 gridview 中删除 strechMode 并将 android:gravity="center" 添加到 custom_trips_frag_row.xml imageview

<GridView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:numColumns="2"
    android:id="@+id/grid"
    android:verticalSpacing="5dp">
</GridView>

Answer 3

浪费了大约4个小时我发现我的代码有错误。我复制了this code of a GridView adapter and found that the GridView didn't show images (or text labels) inside. I tried many answers from Gridview height gets cut, How to have a GridView that adapts its height when items are added，得知我的内景（ImageViews）无法测量它们的宽度和高度。

当然，我可以设置gridView.layoutParams.height = 300，ImageViews会显示，但这取决于ImageView大小。所以，我发现 ImageView 创建错误。

而不是 view = LayoutInflater.from((context)).inflate(R.layout.image_layout, null) 我必须写：

view = LayoutInflater.from((context)).inflate(R.layout.image_layout, parent, false)

在这种情况下，新视图将附加到 GridView 并且可以测量它们的大小。

所以，这里有一个 getView 方法的例子：

override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
    val holder: ViewHolder
    val view: View
    if (convertView == null) {
        holder = ViewHolder()
        view = LayoutInflater.from((context)).inflate(layoutRes, parent, false)
        view.tag = holder
        holder.imageView = view as ImageView
    } else {
        holder = convertView.tag as ViewHolder
        view = convertView
    }
    // Show an image with Glide, for instance.
    with(getItem(position)) {
        showPhoto(holder.imageView, this)
    }
    return view
}

Copy-paste 来自旧手册是一种耻辱。

GridView 中的项目不可见

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