从适配器启动活动不适用于SwipeListView库 [英] Start activity from adapter don't work with SwipeListView library

问题描述

我正在使用 SwipeListView 库，尝试启动活动时出现错误在我的适配器中.

I'm using SwipeListView library and I'm getting error when trying to start an activity in my adapter.

public class ProductAdapter extends ArrayAdapter<Product> {

private Context context;

public ProductAdapter(Context context, int textViewResourceId, List<Product> objects) {
    super(context, textViewResourceId, objects);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder viewHolder;

    final Product product = getItem(position);

    if (convertView == null) {
        viewHolder = new ViewHolder();

        convertView = LayoutInflater.from(getContext()).inflate(R.layout.cproduct_list_item, null);

        viewHolder.nom = (TextView) convertView.findViewById(R.id.name);
        viewHolder.commerce = (TextView) convertView.findViewById(R.id.commerce);
        viewHolder.prix = (TextView) convertView.findViewById(R.id.price);
        viewHolder.bAction1 = (Button) convertView.findViewById(R.id.example_row_b_action_1);
        viewHolder.bAction2 = (Button) convertView.findViewById(R.id.example_row_b_action_2);
        viewHolder.bAction3 = (Button) convertView.findViewById(R.id.example_row_b_action_3);

        convertView.setTag(viewHolder);

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

    viewHolder.nom.setText(product.getName());
    viewHolder.commerce.setText(product.getCommerce());
    viewHolder.prix.setText(String.format("%s F", product.getPrice()));

    viewHolder.bAction1.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(context, MainActivity.class);
            context.startActivity(intent);
        }
    });

    return convertView;
}

private class ViewHolder {
    TextView nom;
    TextView commerce;
    TextView prix;
    Button bAction1;
    Button bAction2;
    Button bAction3;
}
}

当我单击按钮时，出现以下错误:应用程序意外停止".但是，当我使用Toast时，效果很好.我认为开始活动有些矛盾.

When I click on the button I get this error: "The application has stopped unexpectedly". But when I use a Toast, it works fine. I think there is something inconsistent with starting activity.

Logcat:

04-16 18:42:29.531:E/AndroidRuntime(29813):致命异常:主要 04-16 18:42:29.531:E/AndroidRuntime(29813):java.lang.NullPointerException 04-16-16 18:42:29.531:E/AndroidRuntime(29813):位于com.tomsyweb.suna.ProductAdapter $ 2.onClick(ProductAdapter.java:71) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于android.view.View.performClick(View.java:2485) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于android.view.View $ PerformClick.run(View.java:9080) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于android.os.Handler.handleCallback(Handler.java:587) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于android.os.Handler.dispatchMessage(Handler.java:92) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于android.os.Looper.loop(Looper.java:130) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于android.app.ActivityThread.main(ActivityThread.java:3687) 04-16 18:42:29.531:E/AndroidRuntime(29813):at java.lang.reflect.Method.invokeNative(本机方法) 04-16 18:42:29.531:E/AndroidRuntime(29813):at java.lang.reflect.Method.invoke(Method.java:507) 04-16 18:42:29.531:E/AndroidRuntime(29813):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:867) 04-16 18:42:29.531:E/AndroidRuntime(29813):位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 04-16 18:42:29.531:E/AndroidRuntime(29813):在dalvik.system.NativeStart.main(本机方法)

04-16 18:42:29.531: E/AndroidRuntime(29813): FATAL EXCEPTION: main 04-16 18:42:29.531: E/AndroidRuntime(29813): java.lang.NullPointerException 04-16 18:42:29.531: E/AndroidRuntime(29813): at com.tomsyweb.suna.ProductAdapter$2.onClick(ProductAdapter.java:71) 04-16 18:42:29.531: E/AndroidRuntime(29813): at android.view.View.performClick(View.java:2485) 04-16 18:42:29.531: E/AndroidRuntime(29813): at android.view.View$PerformClick.run(View.java:9080) 04-16 18:42:29.531: E/AndroidRuntime(29813): at android.os.Handler.handleCallback(Handler.java:587) 04-16 18:42:29.531: E/AndroidRuntime(29813): at android.os.Handler.dispatchMessage(Handler.java:92) 04-16 18:42:29.531: E/AndroidRuntime(29813): at android.os.Looper.loop(Looper.java:130) 04-16 18:42:29.531: E/AndroidRuntime(29813): at android.app.ActivityThread.main(ActivityThread.java:3687) 04-16 18:42:29.531: E/AndroidRuntime(29813): at java.lang.reflect.Method.invokeNative(Native Method) 04-16 18:42:29.531: E/AndroidRuntime(29813): at java.lang.reflect.Method.invoke(Method.java:507) 04-16 18:42:29.531: E/AndroidRuntime(29813): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 04-16 18:42:29.531: E/AndroidRuntime(29813): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 04-16 18:42:29.531: E/AndroidRuntime(29813): at dalvik.system.NativeStart.main(Native Method)

推荐答案

context在您的情况下是ProductAdapter的字段，并且您不使用任何值对其进行初始化，因此它是null.改用getContext()或用this.context = context初始化context字段.

context is a field of ProductAdapter in your case and you don't initialize it with any value, so it's null. Use getContext() instead or initialize context field with this.context = context.

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