Question

我遇到了一个问题，我有一个listView我使用自定义数组适配器填充，问题是当我使用自定义数组适配器时，存储在ArrayList赢得的数据t显示但如果我使用正常ArrayAdapter，则会显示数据。我需要使用自定义数组适配器来设置listview的样式，因为我无法在正常ArrayAdapter

中设置样式

这是代码： -

CustomAdapter adapter;
  Context context;
  ArrayList<String> data;
  ListView listView;
 private static String newline = System.getProperty("line.separator");

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

    //defining list view
    listView = (ListView)findViewById(R.id.listView);



    //defining data array list to store retrieved data from database
    data = new ArrayList<String>();


    adapter = new CustomAdapter(this,android.R.layout.simple_list_item_1, data);
    listView.setAdapter(adapter);
    context = this;

    Toast.makeText(this,"Loading Please Wait..",Toast.LENGTH_LONG).show();
    new AsyncLoadProdComments().execute();
}



protected class AsyncLoadProdComments extends AsyncTask<Void, JSONObject,
        ArrayList<ProductionCommentsTable>> {

    ArrayList<ProductionCommentsTable> ProductionCommentsTable = null;

    @Override
    protected ArrayList<ProductionCommentsTable> doInBackground(Void... params) {
        // TODO Auto-generated method stub
        RestAPI api = new RestAPI();
        try {
            JSONObject jsonObj = api.GetProductionComments();
            JSONParser parser = new JSONParser();
            ProductionCommentsTable = parser.parseProductionComments(jsonObj);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            Log.d("AsyncLoadProdDetails", e.getMessage());
        }
        return ProductionCommentsTable;
    }

    @Override
    protected void onPostExecute(ArrayList<ProductionCommentsTable> result) {
        // TODO Auto-generated method stub
        for (int i = 0; i < result.size(); i++) {
            //Log.d("Data1", String.valueOf(result));
            data.add("Date: " + result.get(i).getDate().substring(0, 10) + newline + newline +
                    "Item: " + result.get(i).getItem() + newline + newline +
                    result.get(i).getComments());

        }
        adapter.notifyDataSetChanged();

        Toast.makeText(context,"Loading Completed", Toast.LENGTH_SHORT).show();
    }
}

private class CustomAdapter extends ArrayAdapter {

    private Context mContext;
    private int id;
    private List <String>items ;

    public CustomAdapter(Context context, int textViewResourceId , ArrayList<String> list )
    {
        super(context, textViewResourceId, list);
        mContext = context;
        id = textViewResourceId;
        items = list ;
    }

    @Override
    public View getView(int position, View v, ViewGroup parent)
    {
        View mView = v ;
        if(mView == null){
            LayoutInflater vi = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            mView = vi.inflate(id, null);
        }

        if(position % 2 == 0){
            mView.setBackgroundColor(Color.CYAN);
        }else{
            mView.setBackgroundColor(Color.YELLOW);
        }

        return mView;
    }

}

Answer 1

您使用阵列适配器是错误的。它有自己的数组存储数据，所以不要将数据添加到数据数组列表，而是将其添加到适配器。它有方法IOException

Answer 2

假设您的布局'simple_list_item_1'包含带

的TextView

wxFormbuilder

要做一个非常简单的ViewHolder模式实现，在“CustomAdapter”类中添加一个静态类：

android:id="@+id/tv_text"

然后改变你的'getView（）'方法：

static class ViewHolder {
    public TextView tvText1;
}

ViewHolder模式在处理由不同视图组成的列表行时非常有用，因此学习如何使用它当然是值得的。以下链接导致一个很好的 example in SO

自定义数组适配器无法打印数据

2 个答案: