主要用来动态控制子view的摆放位置
TextView textView = new TextView(context);
ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 200);
layoutParams.width=100;
layoutParams.height=200;
textView.setLayoutParams(layoutParams);
构造函数可是设置三种参数
- 固定数值，单位px
- ViewGroup.LayoutParams.MATCH_PARENT ，意思为宽度和父view相同
- ViewGroup.LayoutParams.WRAP_CONTENT，意思为自适应
注意每个view所能获得的layoutparams都是他所对应的父view
比如textview外层包裹着的是一个linearlayout，那么
LinearLayout.LayoutParams layoutParams1 = (LinearLayout.LayoutParams) textView.getLayoutParams();
//设置权重比例
layoutParams1.weight=1;
//设置上部间距
layoutParams1.topMargin=5;
//设置右边间距
layoutParams1.setMarginEnd(20);
//设置四周间距
layoutParams1.setMargins(3,3,3,3);
如果是RelativeLayout：
RelativeLayout.LayoutParams layoutParams1 = (RelativeLayout.LayoutParams) textView.getLayoutParams();
//设置位置居中
layoutParams1.addRule(RelativeLayout.CENTER_IN_PARENT);
//设置在某一个id所对应的view的右边
layoutParams1.addRule(RelativeLayout.RIGHT_OF, R.id.all);
layoutParams1.topMargin=5;
layoutParams1.setMarginEnd(20);
layoutParams1.setMargins(3,3,3,3);
layoutParams1.removeRule(RelativeLayout.CENTER_IN_PARENT);
如果是FrameLayout:
FrameLayout.LayoutParams layoutParams1 = (FrameLayout.LayoutParams) textView.getLayoutParams();
//设置位置居中
layoutParams1.gravity = Gravity.CENTER;
layoutParams1.topMargin = 5;
layoutParams1.setMarginEnd(20);
layoutParams1.setMargins(3, 3, 3, 3);
