如何动态地将ImageView对齐到Constraint Layout的中心？

Question

我是一个有用的助手，可以为您翻译文本。

我正在尝试将图像视图对齐到约束布局的中心。我编写了以下代码，但它不起作用。

代码

int size = 150;
ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams(size, size);

layoutParams.bottomToBottom = ConstraintSet.PARENT_ID;
layoutParams.endToEnd = ConstraintSet.PARENT_ID;
layoutParams.startToStart = ConstraintSet.PARENT_ID;
layoutParams.topToTop = ConstraintSet.PARENT_ID;

circleImageView.setLayoutParams(layoutParams);

- Ashish Tiwari

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你能分享一下你的布局吗？ - magicleon94

在创建新的constraintlayout.layoutparams时，您需要克隆先前的参数。同时，请确保您的imageview高度和宽度为0dp。 - Rahul

Answer 1

约束布局 cLayout = findViewById(R.id.main_layout);

        TextView ev = new TextView(getApplicationContext());
        ev.setText(getString(R.string.not_found_name));
        ev.setTextSize(50);
        ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams( ConstraintLayout.LayoutParams.WRAP_CONTENT,
                ConstraintLayout.LayoutParams.WRAP_CONTENT);

        layoutParams.bottomToBottom = ConstraintSet.PARENT_ID;
        layoutParams.endToEnd = ConstraintSet.PARENT_ID;
        layoutParams.startToStart = ConstraintSet.PARENT_ID;
        layoutParams.topToTop = ConstraintSet.PARENT_ID;

        ev.setLayoutParams(layoutParams);
        cLayout.addView(ev);

- David K. Lee

Answer 2

尝试使用ConstraintSet，您可以轻松地将视图以编程方式渲染到ConstraintLayout中心。

   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    ImageView imageView = new ImageView(this);
    imageView.setImageResource(R.mipmap.ic_launcher);
    imageView.setId(R.id.imageview);

    ConstraintLayout myLayout = new ConstraintLayout(this);
    myLayout.setBackgroundColor(Color.BLUE);

    myLayout.addView(imageView);
    setContentView(myLayout);

    ConstraintSet set = new ConstraintSet();

    set.constrainHeight(imageView.getId(),
            ConstraintSet.WRAP_CONTENT);
    set.constrainWidth(imageView.getId(),
            ConstraintSet.WRAP_CONTENT);

    set.connect(imageView.getId(), ConstraintSet.LEFT,
            ConstraintSet.PARENT_ID, ConstraintSet.LEFT, 0);
    set.connect(imageView.getId(), ConstraintSet.RIGHT,
            ConstraintSet.PARENT_ID, ConstraintSet.RIGHT, 0);
    set.connect(imageView.getId(), ConstraintSet.TOP,
            ConstraintSet.PARENT_ID, ConstraintSet.TOP, 0);
    set.connect(imageView.getId(), ConstraintSet.BOTTOM,
            ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM, 0);

    set.applyTo(myLayout);
}

- Prashant Abdare

Answer 3

在您的代码中：

ConstraintSet.PARENT_ID

这不是父约束布局的真实ID。您需要将其更改为：

R.id.myLayout

其中myLayout是您在*.xml文件中输入的内容：

android:id="@+id/myLayout"

这应该可以正常工作：

int size = 150;
ConstraintLayout.LayoutParams layoutParams = new ConstraintLayout.LayoutParams(size, size);

layoutParams.topToTop = R.id.myLayout;
layoutParams.bottomToBottom = R.id.myLayout;
layoutParams.leftToLeft = R.id.myLayout;
layoutParams.rightToRight = R.id.myLayout;
layoutParams.verticalBias = (float) 0.95;
layoutParams.horizontalBias = (float) 0.5;

circleImageView.setLayoutParams(layoutParams);

- user3348868