1.FrameLayout:帧布局
默认全部以左上角为原点(0,0),每个元素都会覆盖
layout_gravity,上下,左右,居中
2.相对布局RelativeLayout
android:layout_centerInParent="true",在容器中间
android:layout_toLeftOf="@+id/imgCenter"在imgCenter左边
android:layout_alignTop="@+id/imgCenter"和imgCenter上对齐
android:layout_above="@+id/imgCenter"在imgCenter上边
android:layout_alignLeft="@+id/imgCenter"和imgCenter左对齐
android:layout_toRightOf="@+id/imgCenter"在imgCenter右边
android:layout_alignTop="@+id/imgCenter"和imgCenter上对齐
android:layout_below="@+id/imgCenter"在imgCenter下边
android:layout_alignLeft="@+id/imgCenter"和imgCenter左对齐
3,线性布局android:orientation,是水平horizontal还是垂直vertical