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我有一个 listactivity 应用程序，由 5 行组成，每行包含一个 TEXT 和 5 BUTTON，文本和按钮都是可点击的，文本将打开 MyDay 活动，即 textview，当您单击任何按钮时，它必须打开 videoview 屏幕。

除了将移动设备切换到横向模式并滚动它强制关闭的列表并在MyArrayAdapter Class的这一行 (51) 中的 logcat 报告中给出NullPointerException之外，每件事都运行得很好。

日志猫： 

  java.lang.NullPointerException
         at com.test.demo.MyArrayAdapter.getView(MyArrayAdapter.java:51)

MyArrayAdapter 类中的第 (51) 行是：

   holder.textView.setText(s);

任何建议将不胜感激，以解决这个问题，谢谢。

MyArrayAdapter 类：

 public class MyArrayAdapter extends ArrayAdapter<String> {

private final String[] mClasses;
private Context mContext;
private Typeface tf;
private LayoutInflater mInflater;
private String[] mData = { "button1", "button2", "button3", "button4",
        "button5" };
private int[] ids = { R.id.button1, R.id.button2, R.id.button3,
        R.id.button4, R.id.button5 };

int[][] rowDrawables = { 
        {R.drawable.row_1, R.drawable.row_2, R.drawable.row_3, 
               R.drawable.row_4, R.drawable.row_5},
        {R.drawable.row_6, R.drawable.row_7, R.drawable.row_8, 
               R.drawable.row_9, R.drawable.row_10},
        {R.drawable.row_11, R.drawable.row_12, R.drawable.row_13, 
               R.drawable.row_14, R.drawable.row_15},
        {R.drawable.row_16, R.drawable.row_17, R.drawable.row_18, 
               R.drawable.row_19, R.drawable.row_20},
        {R.drawable.row_21, R.drawable.row_22, R.drawable.row_23, 
               R.drawable.row_24, R.drawable.row_25}};

public MyArrayAdapter(Context context, String[] classes) {
    super(context, 0, classes);
    mClasses = classes;
    mContext = context;
    tf = Typeface.createFromAsset(context.getAssets(), "BFantezy.ttf");
    mInflater = LayoutInflater.from(context);
                     }

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.row, null, true);
        holder = new ViewHolder();
        holder.textView = (TextView) convertView
                .findViewById(R.id.row_label);
        holder.textView.setTypeface(tf);
        holder.bt1 = (Button) convertView.findViewById(R.id.button1);
        holder.bt2 = (Button) convertView.findViewById(R.id.button2);
        holder.bt3 = (Button) convertView.findViewById(R.id.button3);
        holder.bt4 = (Button) convertView.findViewById(R.id.button4);
        holder.bt5 = (Button) convertView.findViewById(R.id.button5);
    } else {
        holder = (ViewHolder) convertView.getTag();}

    String s = mClasses[position];
    holder.textView.setText(s);

    int[] rowDr = rowDrawables[position];
    holder.bt1.setBackgroundResource(rowDr[0]);
    holder.bt2.setBackgroundResource(rowDr[1]);
    holder.bt3.setBackgroundResource(rowDr[2]);
    holder.bt4.setBackgroundResource(rowDr[3]);
    holder.bt5.setBackgroundResource(rowDr[4]);

    holder.textView.setTag(Integer.valueOf(position));
    holder.textView.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
            Integer pos = (Integer) v.getTag();
            Intent ourIntent = new Intent(mContext, MyDay.class);
            ourIntent.putExtra("cheese", mClasses[pos]);
            mContext.startActivity(ourIntent);
        }
    });
    holder.bt1.setTag(Integer.valueOf(position));
    holder.bt1.setOnClickListener(mListener);
    holder.bt2.setTag(Integer.valueOf(position));
    holder.bt2.setOnClickListener(mListener);
    holder.bt3.setTag(Integer.valueOf(position));
    holder.bt3.setOnClickListener(mListener);
    holder.bt4.setTag(Integer.valueOf(position));
    holder.bt4.setOnClickListener(mListener);
    holder.bt5.setTag(Integer.valueOf(position));
    holder.bt5.setOnClickListener(mListener);
    return convertView;
                                 }

static class ViewHolder {
    TextView textView;
    Button bt1, bt2, bt3, bt4, bt5;

                        }

private OnClickListener mListener = new OnClickListener() {

    public void onClick(View v) {
                    Integer realPos = (Integer) v.getTag();
                    int video = 0;
        String night = null;
        for (int i = 0; i < ids.length; i++) {
            if (v.getId() == ids[i]) {
                video = i;
                break;
            }
        }
        Intent i = new Intent(mContext, My_videos.class);
        i.putExtra("video", video);
                    i.putExtra("row", realPos);
        mContext.startActivity(i);
                   }
             };

               }

列表按钮：

 public class ListButtons extends ListActivity {
String classes[] = {"First",  "Second", "Third","Fourth", "Fifth" }; 

@Override
protected void onCreate(Bundle savedInstanceState) {
    this.requestWindowFeature(Window.FEATURE_NO_TITLE); 
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    setListAdapter(new MyArrayAdapter(this, classes));  }}
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