Question

我现在正在实施自定义ListView。当我尝试从TextView更改位于CustomAdaper.xml的{{1}}时。它显示NullPointerException。是不是可以这样做。请帮我找到它。我很困惑。

以下是我的 MainActivity.java 代码：

MainActivity

CustomAdapter.Java

setContentView(R.layout.activity_main);
txt_Position = (TextView)findViewById(R.id.txtposition);//still ok
txt_memberName = (TextView)findViewById(R.id.txtmemberName);// still ok

LayoutParams params = (LayoutParams) layout_Date.getLayoutParams();
LayoutParams params1 = (LayoutParams) layout_List.getLayoutParams();
LayoutParams params2 = (LayoutParams) layout_Rotation.getLayoutParams();

     int screenSize = getResources().getConfiguration().screenLayout &
                Configuration.SCREENLAYOUT_SIZE_MASK;

        switch(screenSize) {

        case Configuration.SCREENLAYOUT_SIZE_LARGE:
            Toast.makeText(this, "Large", Toast.LENGTH_LONG).show();

            params.height = 100;
            params1.height = 330 ;
            params2.height = 200;
            txt_Position.setTextSize((float)18.0); //locate in CustomAdapter.xml and this is the line logCat Error Pointed .
            break;

}

这是CustomAdapter.xml

public class CustomAdapter extends BaseAdapter   {

private Activity activity;
private ArrayList data;
private static LayoutInflater inflater=null;
public Resources res;
ListModel getList;
int size ;
int i=0;


public CustomAdapter(Activity a, ArrayList d,Resources resLocal, int size) {


    activity = a;
    data=d;
    res = resLocal;
    this.size = size;

    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

}


public int getCount() {

    if(data.size()<=0)
        return 1;
    return data.size();
}

public Object getItem(int position) {
    return position;
}

public long getItemId(int position) {
    return position;
}


public static class ViewHolder{

    public TextView txt_Name;
    public TextView txt_Status;
    public TextView txt_Position;
    public ImageButton imgbtn_senka;
    public ImageButton imgbtn_fuenka;
    //public TableRow tblrow_btn;
    public RelativeLayout layoutbtn;
    public ImageView image;

}


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

    View vi=convertView;
    final ViewHolder holder;

    if(convertView==null){

        /********** Inflate tabitem.xml file for each row ( Defined below ) ************/
        vi = inflater.inflate(R.layout.customadapter, null);


        holder=new ViewHolder();
        holder.txt_Name = (TextView)vi.findViewById(R.id.txtmemberName);
        holder.txt_Status = (TextView)vi.findViewById(R.id.txtmemberStatus);
        holder.image = (ImageView)vi.findViewById(R.id.imgPlayer);
        holder.imgbtn_fuenka = (ImageButton) vi.findViewById(R.id.btnfusenka);
        holder.imgbtn_senka = (ImageButton) vi.findViewById(R.id.btnsenka);
        holder.txt_Position = (TextView)vi.findViewById(R.id.txtposition);
        holder.layoutbtn = (RelativeLayout)vi.findViewById(R.id.layoutbutton);

        vi.setTag(holder);
    }
    else
        holder=(ViewHolder)vi.getTag();

    if(data.size()<=0)
    {
        holder.txt_Name.setText("No Data");

    }
    else
    {


        getList=null;
        getList = (ListModel) data.get(position);

        if(getList.getMemberStatus() == 3){


            holder.txt_Status.setVisibility(View.INVISIBLE);
            holder.imgbtn_fuenka.setVisibility(View.VISIBLE);
            holder.imgbtn_senka.setVisibility(View.VISIBLE);

            if(getList.getEntry() == 1){

                holder.imgbtn_senka.setImageResource(R.drawable.sankagray);
                holder.imgbtn_senka.setEnabled(false);

            }

            else if(getList.getEntry() == 0){

                holder.imgbtn_fuenka.setImageResource(R.drawable.fusankagray);
                holder.imgbtn_fuenka.setEnabled(false);


            }

            holder.imgbtn_senka.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {

                    String entry = "1";

                    CustomListViewAndroidExample sct = (CustomListViewAndroidExample)activity;
                    sct.updateData(position , entry);
                    holder.imgbtn_senka.setImageResource(R.drawable.sankagray);
                    holder.imgbtn_senka.setEnabled(false);
                    holder.imgbtn_fuenka.setEnabled(true);
                    holder.imgbtn_fuenka.setImageResource(R.drawable.fusanka);



                }
            });

            holder.imgbtn_fuenka.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {

                    String entry = "0";

                    CustomListViewAndroidExample sct = (CustomListViewAndroidExample)activity;
                    sct.updateData(position , entry);
                    holder.imgbtn_fuenka.setImageResource(R.drawable.fusankagray);
                    holder.imgbtn_fuenka.setEnabled(false);
                    holder.imgbtn_senka.setEnabled(true);
                    holder.imgbtn_senka.setImageResource(R.drawable.sanka);



                }
            });
        }

        else{


            holder.txt_Status.setVisibility(View.VISIBLE);
            holder.imgbtn_fuenka.setVisibility(View.INVISIBLE);
            holder.imgbtn_senka.setVisibility(View.INVISIBLE);
            if(getList.getEntry() == 0){
                holder.txt_Status.setText("未確認");
            }
            else if(getList.getEntry() == 1){
                holder.txt_Status.setText("参加");
            }

            else if(getList.getEntry() == 2){
                holder.txt_Status.setText("不参加");
            }
            else if(getList.getEntry() == 3){
                holder.txt_Status.setText("取消");
            }
        }





         holder.txt_Name.setText(getList.getMemberName());
         holder.txt_Position.setText(getList.getPosition());
         String url="http://10.0.2.2/football365/Photo/"+getList.getImage();

         try {
            Bitmap bitmap= BitmapFactory.decodeStream((InputStream) new URL(url).getContent());
            Bitmap resized = Bitmap.createScaledBitmap(bitmap, 76, 76, false);
            holder.image.setImageBitmap(resized);
        }
        catch (MalformedURLException e) {

            e.printStackTrace();
        } catch (IOException e) {

            e.printStackTrace();
        }
        // holder.image.setImageResource(res.getIdentifier("http://10.0.2.2/football365/Photo/"+getList.getImage(),null,null));


    }

    if(size == 1){

        holder.txt_Name.setTextSize((float)20.0);

    }

    return vi;
}

public void changeSize(){

    ViewHolder holder = new ViewHolder();
    holder.txt_Position.setTextSize((float)18.0);
    holder.txt_Name.setTextSize((float)20.0);
}

Answer 1

试试这个：

txt_Position.setTextSize(TypedValue.COMPLEX_UNIT_DIP, Float.parseFloat(18.0));

Answer 2

尝试这个

txt_Position.setTextSize(TypedValue.COMPLEX_UNIT_SP, 18);

在运行时更改自定义列表视图中的TextView文本大小

2 个答案: