Question

我创建了一个在特定时间重复的动态视图。视图有2个textViews和2个带默认值的单选按钮。我想从程序中更改Text值但是获取nullpointer异常，这是我的代码：

    LayoutInflater inflater = (LayoutInflater)context.getSystemService
            (Context.LAYOUT_INFLATER_SERVICE);
    LinearLayout scrollViewLinearlayout = (LinearLayout)findViewById(R.id.parent); // The layout inside scroll view
    //int count=50;
    for(int i = 0; i < Studentlist.length; i++){
        String data = Studentlist[i];
        String RollNum = data.split("--")[0];
        String Name = data.split("--")[1];

        LinearLayout layout2 = new LinearLayout(context);
        layout2.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
        View item = inflater.inflate(R.layout.item_layout, null, false);

        layout2.addView(item);
        layout2.setId(i);
        TextView trollnum = (TextView)findViewById(R.id.RollNum);
        trollnum.setText(RollNum);
        TextView tname = (TextView)findViewById(R.id.Name);
        tname.setText(Name);
        scrollViewLinearlayout.addView(layout2);


        Log.d("Id is: ", trollnum.getText().toString());

我在'trollnum.setText（RollNum）;'

获得nullpointer

如何更改视图中的文字？

Answer 1

您正试图在活动的布局中找到不存在的视图，而不是在刚刚充气的布局中找到它。

替换

TextView trollnum = (TextView)findViewById(R.id.RollNum);
TextView tname = (TextView)findViewById(R.id.Name);

使用

TextView trollnum = (TextView) item.findViewById(R.id.RollNum);
TextView tname = (TextView) item.findViewById(R.id.Name);

NullPointer在android中使用动态视图时

1 个答案: