java - 在生成的 TextView 上以编程方式设置边距时出错

Question

我生成这样的 TextView :

   TextView myView  = new TextView(this);
   myView.setText(Html.fromHtml(myString));
   linearLayout2.addView(myView);

当我将此代码更改为设置边距时:

   TextView myView  = new TextView(this);
   myView.setText(Html.fromHtml(myString));
   LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)myView.getLayoutParams();
   params.setMargins(20, 0, 0, 0);
   myView.setLayoutParams(params);
   linearLayout2.addView(myView);

我收到此错误:

Unable to start activity ComponentInfo{com.example./com.example.Activity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.LinearLayout$LayoutParams.setMargins(int, int, int, int)' on a null object reference

如何消除这个错误？

谢谢。

Answer 1

你应该创建new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT)

而不是从 View 中获取它们。