Question

主要课程：

recyclerView = (RecyclerView)findViewById(R.id.card_recycler_view);
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getApplicationContext(),2);
        recyclerView.setLayoutManager(layoutManager);

            Retrofit retrofit = new Retrofit.Builder()
                    .baseUrl("http://192.168.0.2/littlezebra/scripts/")
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();

            login service = retrofit.create(login.class);


            Call<dashboard> call = service.dash();

            call.enqueue(new Callback<dashboard>() {
                @Override
                public void onResponse(Call<dashboard> call, Response<dashboard> response) {

                  dashboard  dashboard = response.body();
                    data = new ArrayList<>(Arrays.asList(dashboard. getDashboard_info()));
                    adapter = new DataAdapter(data,context);
                    recyclerView.setAdapter(adapter);

                }

适配器类：

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {
    private ArrayList<dashboard.Dashboard_info> android;
    private Context context;

    public DataAdapter(ArrayList<dashboard.Dashboard_info> android,Context context) {
        this.android = android;
        this.context = context;
    }


    public DataAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
     View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_row, viewGroup, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(DataAdapter.ViewHolder viewHolder, int i) {

        viewHolder.tv_name.setText(android.get(i).getId());
        Picasso.with(context).load(android.get(i)
                .getWeek_image())
                .resize(250,200) //to resize Image
                .into(viewHolder.img_android);
        viewHolder.tv_api_level.setText(android.get(i).getWeek_name());
    }

    @Override
    public int getItemCount() {
        return android.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        private TextView tv_name;
        private ImageView img_android;
        private TextView tv_api_level;
        public ViewHolder(View view) {
            super(view);

            tv_name = (TextView)view.findViewById(R.id.tv_name);
            img_android = (ImageView) view.findViewById(R.id.img_android);
            tv_api_level = (TextView)view.findViewById(R.id.tv_api_level);

        }
    }

过程：

com.example.admin.myappl，PID：5047 java.lang.IllegalArgumentException：Context不能为null。在com.squareup.picasso.Picasso $ Builder。（Picasso.java:701）com.squareup.picasso.Picasso.with（Picasso.java:662）at com.example.admin.myappl.Adapter.DataAdapter.onBindViewHolder（ DataAdapter.java:37）在com.example.admin.myappl.Adapter.DataAdapter.onBindViewHolder（DataAdapter.java:18）在android.support.v7.widget.RecyclerView $ Adapter.onBindViewHolder（RecyclerView.java:6400）在android .support.v7.widget.RecyclerView $ Adapter.bindViewHolder（RecyclerView.java:6433）at android.support.v7.widget.RecyclerView $ Recycler.tryBindViewHolderByDeadline（RecyclerView.java:5377）at android.support.v7.widget.RecyclerView android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition（RecyclerView.java:5482）在android.support.v7.widget.RecyclerView $ Recycler.getViewForPosition（RecyclerView.java）上的$ Recycler.tryGetViewHolderForPositionByDeadline（RecyclerView.java:5640）：5478）在android.support.v7.widget.Grid的android.support.v7.widget.LinearLayoutManager $ LayoutState.next（LinearLayoutManager.java:2215）在Android.support.v7.widget.LinearLayoutManager.onLayoutChildren（LinearLayoutManager.java：595）的android.support.v7.widget.LinearLayoutManager.fill（LinearLayoutManager.java:1502）上的LayoutManager.layoutChunk（GridLayoutManager.java:556）位于android.support.v7.widget.RecyclerView.dispatchLayoutStep2（RecyclerView.java:3625）的android.support.v7.widget.RecyclerView.dispatchLayout（RecyclerView）中的.support.v7.widget.GridLayoutManager.onLayoutChildren（GridLayoutManager.java:170） .java：3354）在android.view.View.layout（ViewGroup）的android.view.View.layout（View.java:17838）的android.support.v7.widget.RecyclerView.onLayout（RecyclerView.java:3886）。 java：5754）在android.view.View.layout（ViewGroup.java:5754）的android.view.View.layout（View.java:17838）的android.widget.RelativeLayout.onLayout（RelativeLayout.java:1189）在android.support.design.widget.ViewOffsetBehavior.on上的android.support.design.widget.HeaderScrollingViewBehavior.layoutChild（HeaderScrollingViewBehavior.java:131） LayoutChild（ViewOffsetBehavior.java:42）在android.support.design.widget.AppBarLayout $ ScrollingViewBehavior.onLayoutChild（AppBarLayout.java:1389）在android.support.design.widget.CoordinatorLayout.onLayout（CoordinatorLayout.java:868）在android .view.View.layout（View.java:17838）在android.view.Layout.onLayout（DrawerLayout.java:1192）的android.view.ViewGroup.layout（ViewGroup.java:5754）。在Android.widget.FrameLayout.onLayout的android.widget.FrameLayout.layoutChildren（FrameLayout.java:383）的android.view.ViewGroup.layout（ViewGroup.java:5754）的view.View.layout（View.java:17838）（FrameLayout.java:321）在android.view.Loutout.setChildFrame的android.view.View.layout（ViewGroup.java:5754）上的android.view.View.layout（View.java:17838）（LinearLayout.java： 1982年在android.widget.LinearLayout.onLayout（LinearLayout.java：1735）的android.widget.LinealLayout.onoutVertical（LinearLayout.java:1835）安卓android.view.View.layout（View.java:17838）。 view.Vi ewGroup.layout（ViewGroup.java:5754）在Android.widget.FrameLayout.layout中的android.widget.FrameLayout.layoutChildren（FrameLayout.java:383）处于android.view.View.layout（ViewLayout.java:321） .java：17838）在Android.widget.LinearLayout.setoutVertical（LinearLayout.java:1826）的android.widget.LinearLayout.setChildFrame（LinearLayout.java:1982）的android.view.ViewGroup.layout（ViewGroup.java:5754）在android.widget.Linout.onLayout（LinearLayout.java:1735）的android.view.Viewout上的android.view.View.layout（View.java:17838）处于android.widget上。在android.view.View的com.android.internal.policy.DecorView.onLayout（DecorView.java:751）的android.widget.FrameLayout.onLayout（FrameLayout.java:321）中的FrameLayout.layoutChildren（FrameLayout.java:383） .layout（View.java:17838)08-16 17:01:40.928 5047-5047 / com.example.admin.myappl E / AndroidRuntime：在Android的android.view.ViewGroup.layout（ViewGroup.java:5754）。 view.ViewRootImpl.performLayout（ViewRootImpl.java:2722）
在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1473）的android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:6976）上的android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:2395）

Answer 1

请

也许问题出在这里： Picasso.with（上下文）.load（ “http://i.imgur.com/DvpvklR.png”）代入（ImageView的）;

Answer 2

如错误所示，您将null上下文对象传递给Picasso.with()方法。

要解决此问题，您可以在onBindViewHolder()方法中执行类似操作：

//inside onBindViewHolder ()
Picasso.with(holder.itemView.getContext()).load("url here").into(yourImageView);

因此，您可以看到，您甚至不需要在构造函数中将上下文传递给适配器。

Answer 3

将 adapter = new DataAdapter(data,context);行更改为adapter = new DataAdapter(data,YourActivity.this);

然后，转到适配器类，

并粘贴

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {
    private ArrayList<dashboard.Dashboard_info> android;
    private Activity activity;

    public DataAdapter(ArrayList<dashboard.Dashboard_info> android,Activity activity) {
        this.android = android;
        this.activity = activity;
    }

现在使用毕加索

Picasso.with(activity).load(android.get(i)
                .getWeek_image())
                .resize(250,200) 
                .into(viewHolder.img_android);

毕加索在网格视图中回收视图改造2

3 个答案: