先看代码
LinearLayout layout=new LinearLayout(this);
TextView tv=new TextView(this);
ViewGroup.LayoutParams params=new ViewGroup.LayoutParams(100,100);
tv.setLayoutParams(params);
layout.addView(tv);
这个代码是没问题的,接着看下一个
LinearLayout layout=new LinearLayout(this);
TextView tv=new TextView(this);
ViewGroup.LayoutParams params=new ViewGroup.LayoutParams(100,100);
layout.addView(tv);
tv.setLayoutParams(params);
上面这个代码是有问题的,会抛出 ClassCastException
ViewGroup.LayoutParams不能强转为LinearLayout.LayoutParams。