使用ConstraintSet实现布局控件动画

话不多说,直接上代码

MainActivity.class

    private ConstraintSet constraintSet1;
    private ConstraintSet constraintSet2;
    ConstraintLayout constraintLayout;
    boolean old = true;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityMain1Binding binding = DataBindingUtil.setContentView(this, R.layout.activity_main1);
        constraintLayout = (ConstraintLayout) binding.getRoot();
        constraintSet1 = new ConstraintSet();
        constraintSet1.clone(constraintLayout);
        constraintSet2 = new ConstraintSet();
        constraintSet2.clone(this,R.layout.activity_main2);
        binding.setOnClick(this);
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    @Override
    public void onClick(View v) {
        TransitionManager.beginDelayedTransition(constraintLayout);
        if (old = !old){
            constraintSet1.applyTo(constraintLayout);
        }else{
            constraintSet2.applyTo(constraintLayout);
        }
    }

activity_main1.xml

 <android.support.constraint.ConstraintLayout
        android:id="@+id/cl_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <ImageView
            android:id="@+id/iv"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/ic_launcher"/>

        <Button
            android:onClick="@{onClick}"
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="切换动画"
            android:textSize="14dp"
            android:textColor="@color/colorPrimary"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />


    </android.support.constraint.ConstraintLayout>

activity_main2.xml

   <android.support.constraint.ConstraintLayout
        android:id="@+id/cl_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">


        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="切换动画"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent" />


    </android.support.constraint.ConstraintLayout>

最后总结下几个注意事项:
constrainset , 动画基于布局文件,需要两个约束位置不同的布局

1. 根布局必须为constrainlayout

2. 子view都必须有id

3. 动画只支持 约束条件的变化,view的属性修改无效,像text view的字体大小,颜色.

4. 动画布局可以只包含要做动画的布局,其他可以舍弃(activity_main1比activity_main2多了一个image view)

   github 地址