java - Android:在 Java 代码中更改 layout_constraintStart point 和 layout_margin

Question

我的设计中有 3 个按钮。

按钮3可以根据条件可见或不可见。

现在 3 个按钮位于屏幕中央。如果其中之一将可见，我想自动更改设计。

此外，我还有一个活跃的条形标记。我想在单击按钮时更改此标记的 constraintStart。

提前致谢

Screenshot

这是我的 XML:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    android:orientation="vertical"

    tools:layout_editor_absoluteX="0dp"
    tools:layout_editor_absoluteY="25dp">


    <Button
        android:id="@+id/btn1"
        style="?android:attr/borderlessButtonStyle"
        android:layout_width="100dp"
        android:layout_height="40dp"
        android:layout_marginStart="8dp"
        android:text="Button1"
        android:textSize="14sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/btn2" />

    <Button
        android:id="@+id/btn2"
        style="?android:attr/borderlessButtonStyle"
        android:layout_width="100dp"
        android:layout_height="40dp"
        android:layout_marginStart="16dp"
        android:text="Button2"
        android:textSize="14sp"
        app:layout_constraintBottom_toBottomOf="@+id/btn3"
        app:layout_constraintStart_toEndOf="@+id/btn1" />

    <Button
        android:id="@+id/btn3"
        style="?android:attr/borderlessButtonStyle"
        android:layout_width="120dp"
        android:layout_height="40dp"
        android:layout_marginRight="24dp"
        android:layout_marginTop="16dp"
        android:text="button3"
        android:textSize="14sp"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imgActiveBar"
        android:layout_width="103dp"
        android:layout_height="4dp"
        android:layout_marginStart="8dp"
        android:background="@android:color/holo_blue_dark"
        android:scaleType="centerCrop"
        app:layout_constraintStart_toStartOf="@+id/btn1"
        app:layout_constraintTop_toBottomOf="@+id/btn1" />


</android.support.constraint.ConstraintLayout>

这是我的 Java 代码:

package au.com.test.listviewtest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class TestActivity extends AppCompatActivity {
 private boolean bCondition = false;
    private Button btn1 = null;
    private Button btn2 = null;
    private Button btn3 = null;
    private ImageView imgActiveBar = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);

        btn1 = (Button) findViewById(R.id.btn1);
        btn2 = (Button) findViewById(R.id.btn2);
        btn3 = (Button) findViewById(R.id.btn3);
        imgActiveBar = (ImageView) findViewById(R.id.imgActiveBar);


        if (bCondition==true){
            btn3.setVisibility(View.INVISIBLE);
            //If bt3 is invisible than
            // make btn1 an btn2 centered


        } else {
            btn3.setVisibility(View.VISIBLE);
            //If bt3 is visible than
            // make btn1 an btn2 and bt3 centered

        }

        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
            // make ActiveBar's layout_constraintStart_toStartOf is bt1
            }
        });
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // make ActiveBar's layout_constraintStart_toStartOf is bt2
            }
        });
        btn3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // make ActiveBar's layout_constraintStart_toStartOf is bt3
            }
        });


    }
}

Answer 1

您需要更改 imgActiveBar 布局参数的 startToStart 字段:

 ConstraintLayout.LayoutParams prams = (ConstraintLayout.LayoutParams) imgActiveBar.getLayoutParams();
 prams.startToStart = btn1.getId(); //for example
 //you'll probably need to change the end position as well
 prams.endToEnd = btn1.getId();
 imgActiveBar.setLayoutParams(prams);
 imgActiveBar.requestLayout();

此行为由 TabLayout 实现