如何在MainActivity类中向布局文件添加一个编辑框,编辑框组件设置id为et_miyue,需要输入文本
EditText et_miyue=new EditText(null);
et_miyue.setHint("请输入密钥...");
et_miyue.setSingleLine(true);
et_miyue.setAlpha(getWallpaperDesiredMinimumWidth());
et_miyue.setX(BIND_ABOVE_CLIENT);
RelativeLayout relative = new RelativeLayout(this);
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
relative.addView(et_miyue, lp);
setContentView(relative);
上面代码是我自己写的,运行时出错,空指针异常,打不开界面,我想要将其布局到layout.xml中,现在MainActivity的布局文件为layout.xml文件