为什么我的Android自定义适配器样式随机行？

Question

我有一个简单的自定义适配器，用于显示度数列表。 我正在尝试添加一种方法来使列表中的子标题具有相似的内容。 每行都有一个标题和描述，所以我要做的是将描述设置为null的行膨胀时，它会更改行的样式（隐藏描述并使标题居中）。 我遇到的问题是将样式应用于随机行，而不是仅将其应用于具有空值的样式（随机行的标题将居中，而其他随机行的描述将被隐藏）我的getView：

public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    if(v == null) {
        LayoutInflater inflater = LayoutInflater.from(mContext);
        v = inflater.inflate(R.layout.links_list, null);
    }

    TextView tvTitle = (TextView)v.findViewById(R.id.txtTitle);
    TextView tvDesc = (TextView)v.findViewById(R.id.txtDesc);

    if(mainList.get(position) instanceof Program) {
        Program row = (Program) mainList.get(position);
        if(row.getTitle() != null && row.getType() == null) {
            //this condition should style just the ones with null type, but style random rows instead
            tvTitle.setText(row.getTitle());
            tvTitle.setGravity(Gravity.CENTER);
            tvDesc.setVisibility(View.GONE);
        } else {
            if(row.getTitle() != null) {
                tvTitle.setText(row.getTitle());
            }
            if(row.getType() != null) {
                tvDesc.setText(row.getType());
            }
        }
    }

    return v;
}

所以我的问题是，为什么这种样式会随机排列行而不是我告诉它的行？

Answer 1

if(mainList.get(position) instanceof Program) {
        Program row = (Program) mainList.get(position);
        if(row.getTitle() != null && row.getType() == null) {
            //this condition should style just the ones with null type, but style random rows instead
            tvTitle.setVisibility(View.VISIBLE);
            tvTitle.setText(row.getTitle());
            tvTitle.setGravity(Gravity.CENTER);
            tvDesc.setVisibility(View.GONE);
        } else {
            tvTitle.setVisibility(View.GONE);
            tvTitle.setGravity(Gravity.LEFT);
            tvDesc.setVisibility(View.VISIBLE);
            if(row.getTitle() != null) {
                tvTitle.setText(row.getTitle());
            }
            if(row.getType() != null) {
                tvDesc.setText(row.getType());
            }
        }
    }