Question

我正在尝试实施Picasso来帮助将图片加载到GridView。目前，下面的代码运行没有任何问题，但GridView项只是空白。我知道特定ImageView实际存在，因为如果我选择它并按住，selected_state drawable就会被激活，正如您在this屏幕截图中看到的那样。

你能帮我找到问题吗？谢谢！

GalleryFragment.java：

//in onCreateView()
v = inflater.inflate(R.layout.fragment_gallery, parent, false);

GridView gridView = (GridView) v.findViewById(R.id.fragmentGalleryGridview);
gridView.setAdapter(new GalleryAdapter(getActivity()));
gridView.setOnScrollListener(new GalleryScrollListener(getActivity()));

return v;

GalleryAdapter.java延伸BaseAdapter：

public GalleryAdapter(Context mContext)
{
    this.mContext = mContext;
    inflater = LayoutInflater.from(mContext);
    //get ArrayList<String> mPaths from SQLite database
}

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    SquareImageView view = (SquareImageView) convertView;

    if (view == null)
    {
        view = new SquareImageView(mContext);
        view.setScaleType(ImageView.ScaleType.CENTER_CROP);
    }

    Picasso.with(mContext)
            .load(mPaths.get(position))
            .fit()
            .into(view);

    return view;
}

SquareImageView.java：

public class SquareImageView extends ImageView
{
    //three constructors

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        setMeasuredDimension(getMeasuredWidth(), getMeasuredWidth());
    }
}

fragment_gallery.xml：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#eeeeee"
    android:layout_marginTop="?android:attr/actionBarSize">

    <GridView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/fragmentGalleryGridview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="5dp"
        android:columnWidth="100dp"
        android:numColumns="auto_fit"
        android:verticalSpacing="5dp"
        android:horizontalSpacing="5dp"
        android:drawSelectorOnTop="true"
        android:stretchMode="columnWidth"/>

</FrameLayout>

Answer 1

这就是我使用GridLayout成功实现Picasso库的方法...... GridView要求您对项目使用ListAdapter，我遇到了同样的问题但是使用GridLayout解决了它代替：

public class ImageHandler {

    private static Picasso instance;

    public static Picasso getSharedInstance(Context context)
    {
        if(instance == null)
        {
            instance = new Picasso.Builder(context).executor(Executors.newSingleThreadExecutor()).memoryCache(Cache.NONE).indicatorsEnabled(true).build();
            return instance;
        }
        else
        {
            return instance;
        }
    }
}

在我实现这个类后，我是如何访问代码并将图像加载到我的ImageView中，ImageView是GridLayout的一部分。

// imString = "http://filepath.file.jpg" as example


        LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        GridLayout grid = (GridLayout) findViewById(R.id.viewAllGrid);
        grid.canScrollVertically(1);
        ImageButton image;

        for(int i = 0; i < itemsList.size(); i++){
            aContainer= (LinearLayout) inflater.inflate(R.layout.layout_container, null);
            image = (ImageButton) aContainer.findViewById(R.id.imageViewOrButton);
            ImageHandler.getSharedInstance(getApplicationContext()).load(imString).skipMemoryCache().fit().into(image);
            grid.addView(aContainer);
        }

这是layout_container

<LinearLayout
    android:orientation="vertical"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingRight="10dp"
    android:id="@+id/Container"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <ImageButton
        android:layout_width="100dp"
        android:layout_height="130dp"
        android:background="@null"
        android:id="@+id/seriesThumbnail"/>

    <TextView
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textStyle="bold"
        android:textColor="#ffffffff"
        android:id="@+id/title"
        android:autoText="false"
        android:ellipsize="end"
        android:maxLines="1" />

    <TextView
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:id="@+id/publisher"
        android:text="Francis Chan"
        android:maxLines="1"
        android:ellipsize="end" />

</LinearLayout>

这是viewAllGrid布局架构

<GridLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:paddingLeft="20dp"
            android:id="@+id/viewAllGrid"
            android:layout_gravity="center_horizontal"
            android:columnCount="3"
            android:layout_weight=".8"
            android:orientation="horizontal">
        </GridLayout>

Answer 2

我遇到了同样的问题，因为我错过了权限

<!-- This is required for Picasso to work. -->
<uses-permission android:name="android.permission.INTERNET"/>

<!-- The following permissions are OPTIONAL. -->

<!-- Used to adjust the work load depending on the type of network the device is using. -->
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

在GridView中使用Picasso：ImageView在那里，但没有图像

2 个答案: