java - 在 twoway-gridView 中访问 TextView

Question

我想在双向 GridView 中使用 TextView https://github.com/jess-anders/two-way-gridview .我可以成功地将 ArrayAdapter 与双向 GridView 一起使用。它按我的意愿正常工作。但是当我改编来自 How to add a TextView to a GridView in Android 的示例时.
访问 TextView 时出现 NullPointerException。
这是我的代码。
MainActivity.java :

public class MainActivity extends AppCompatActivity {
    static final String[] numbers = new String[] {
            "A", "B", "C", "D", "E",
            "F", "G", "H", "I", "J",
            "K", "L", "M", "N", "O",
            "P", "Q", "R", "S", "T",
            "U", "V", "W", "X", "Y", "Z"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        TwoWayGridView gridview = (TwoWayGridView) findViewById(R.id.gridview);
        gridview = (TwoWayGridView) findViewById(R.id.gridview);
//        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
//                android.R.layout.simple_list_item_1, numbers);
        TextViewAdapter adapter = (TextViewAdapter) new TextViewAdapter(this, numbers);
        gridview.setAdapter(adapter);

    }

}

layout.xml :

<?xml version="1.0" encoding="utf-8"?>
<com.jaikra.sarit.wecare.TwoWayGridView.TwoWayGridView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/gridView1"
    android:numColumns="auto_fit"
    android:gravity="center"
    android:columnWidth="100dp"
    android:stretchMode="columnWidth"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

</com.jaikra.sarit.wecare.TwoWayGridView.TwoWayGridView>

item.xml :

<TextView
    android:id="@+id/grid_item_label"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@+id/label"
    android:layout_marginTop="5px"
    android:textSize="15px"
    xmlns:android="http://schemas.android.com/apk/res/android">
</TextView>

TextViewAdapter.java :

public class TextViewAdapter extends BaseAdapter {
    private Context context;
    private final String[] textViewValues;

    public TextViewAdapter(Context context, String[] textViewValues) {
        this.context = context;
        this.textViewValues = textViewValues;
    }

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

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View gridView;

        if (convertView == null) {

            gridView = new View(context);

            gridView = inflater.inflate(R.layout.layout, null);

            // set value into textview
            TextView textView = (TextView) gridView
                    .findViewById(R.id.grid_item_label);
            textView.setText(this.textViewValues[position]);

            textView.setTextColor(Color.GREEN);

        } else {
            gridView = (View) convertView;
        }

        return gridView;
    }
}

问题:

FATAL EXCEPTION: main java.lang.NullPointerException at com.jaikra.sarit.wecare.TextViewAdapter.getView(TextViewAdapter.java:54)

错误:
这是第 54 和 55 行。

    TextView textView = (TextView) gridView
            .findViewById(R.id.grid_item_label);
    textView.setText(this.textViewValues[position]);

问题:如何解决这个问题？
我需要阅读什么样的编程主题？

经过多次尝试:
我开始相信 twoway-gridview 在幕后有一些与普通 gridView 不同的想法。我已经向原始开发人员公开了这个问题，但欢迎在这里提供任何帮助。

Answer 1

对于 GridView 的项目，你应该inflate

View view = inflater.inflate(R.layout.item, null);
TextView textView= (TextView)view.findViewById(R.id.label);
textView.setText(this.textViewValues[position]);
textView.setTextColor(Color.GREEN);

希望这对您有所帮助。

更新

@Override
    public View getView(int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View gridView;

        if (convertView == null) {
            gridView = inflater.inflate(R.layout.item, null);

            // set value into textview
            TextView textView = (TextView) gridView.findViewById(R.id.label);
            textView.setText(this.textViewValues[position]);

            textView.setTextColor(Color.GREEN);

        } else {
            gridView = (View) convertView;
        }

        return gridView;
    }