多个的基本示例ConstrainLayout
:
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/constLayout_root"
>
<android.support.constraint.ConstraintLayout
android:id="@+id/constLayout_A"
android:layout_width="30dp"
android:layout_height="30dp"
android:background="#ff0"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<android.support.constraint.ConstraintLayout
android:id="@+id/constLayout_B"
android:layout_width="30dp"
android:layout_height="40dp"
android:background="#f0f"
android:visibility="gone"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<android.support.constraint.ConstraintLayout
android:id="@+id/constLayout_C"
android:layout_width="30dp"
android:layout_height="50dp"
android:background="#0f0"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/constLayout_A"
/>
</android.support.constraint.ConstraintLayout>
constLayout_B
叠加constLayout_A
,constLayout_C
现在显示在下方constLayout_A
。
现在我需要以编程方式更改约束并constLayout_C
在下方显示constLayout_B
(并隐藏constLayout_A
)。
我试图以这种方式将它们链接在一起:
final ConstraintSet cs_C = new ConstraintSet();
cs_C.connect(constLayout_C.getId(), ConstraintSet.TOP, constLayout_B.getId(), ConstraintSet.BOTTOM);
cs_C.connect(constLayout_C.getId(), ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM);
cs_C.connect(constLayout_C.getId(), ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.START);
cs_C.connect(constLayout_C.getId(), ConstraintSet.END, ConstraintSet.PARENT_ID, ConstraintSet.END);
cs_C.applyTo(constLayout_C);
final ConstraintSet cs_B = new ConstraintSet();
cs_B.connect(constLayout_B.getId(), ConstraintSet.TOP, ConstraintSet.PARENT_ID, ConstraintSet.TOP);
cs_B.connect(constLayout_B.getId(), ConstraintSet.BOTTOM, constLayout_C.getId(), ConstraintSet.TOP);
cs_B.connect(constLayout_B.getId(), ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.START);
cs_B.connect(constLayout_B.getId(), ConstraintSet.END, ConstraintSet.PARENT_ID, ConstraintSet.END);
cs_B.applyTo(constLayout_B);
我ConstraintSet
的由于某种原因没有被申请。如何constLayout_C
动态更改顶部约束?