java - 以编程方式完成时， View 不反射(reflect)任何更改

Question

The basic view hierarchy is this:secondActivity    linearLayout(LinearLayout)        constLayout(ConstraintLayout)            textbox(TextView)            image(ImageView)            image2            image3            ...

The textbox TextView has visibility GONE, and goal is to make it VISIBLE on clicking other visible siblings, change some colors and text, and when clicked again it must be invisible again and reverse all changes.Cant understand whatever it is that am missing. I have checked many older projects in which I did the same thing and cant find any visible differences as to why this code is not working now.

secondActivity.java

public class secondActivity extends Activity {

    public boolean isTextBoxHidden;
    public ConstraintLayout constLayout;
    public TextView textbox;

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

        constLayout = findViewById(R.id.constLayout);
        textbox = findViewById(R.id.textbox);
        isTextBoxHidden = false;

        // SETTING UP LISTENER
        View.OnClickListener clickListener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(!isTextBoxHidden) {
                    constLayout.setBackgroundColor(Color.BLACK);  //setting color on previously 
                    v.setBackgroundColor(Color.BLACK);            //setting color on visible view

                    textbox.setText("whatever");
                    textbox.setVisibility(View.VISIBLE);  //was gone
                    isTextBoxHidden = true;
                }
                else {
                    textbox.setVisibility(View.GONE);     //hide again
                    constLayout.setBackgroundColor(Color.WHITE);
                    v.setBackgroundColor(Color.WHITE);
                    isTextBoxHidden = false;
                }
            }
        };

        // INSERTING LISTENERS into all children
        for(int i=0; i<constLayout.getChildCount(); i++) {
                constLayout.getChildAt(i).setOnClickListener(clickListener);
        }
    }
}

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="@+id/linearLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".secondActivity">

    <android.support.constraint.ConstraintLayout
        android:id="@+id/constLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/white">

        <TextView
            android:id="@+id/textbox"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="example"

            android:visibility="gone"

            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

        <ImageButton
            android:id="@+id/image"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:scaleType="fitXY"
            android:src="@drawable/example"

            android:clickable="true"

            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"/>

        <!--few more clones of the first imageButton-->

    </android.support.constraint.ConstraintLayout>
</LinearLayout>

Answer 1

我看不到您在哪里设置文本框引用，所以也许这是一个线索。

编辑:是否编译了您提供的示例并且一切正常，但我认为 [...] 再次消失 意味着您可能希望这是一次操作，所以而不是 boolean 只需使用 Boolean 并将其与 null 进行比较。

编辑:再一想，您可以在 else 分支中删除 isTextBoxHidden = false;