View.INVISIBLE和Android的价值之间的差额：隐形

问题描述

我对Android开发新的，所以我在OnClick事件为我设置按钮的方法开发一个简单的应用程序，它隐藏的TextView pressing一些按钮，这样在java code TextView的为不可见，我用：

I'm new on Android development, so I'm developing an simple application that hides a textview pressing some button, so in the java code in the method for the OnClick event for the button I set the textview as invisible, I used:

textView.setVisibility(1);

由于1是隐形的值Android的参考，但它不工作，所以我用后

because 1 is the value for "invisible" described in the android reference, but it does not work, so after I used

textView.setVisibility(View.INVISIBLE);

和它的作品，所以当使用1的价值呢？而为什么View.INVISIBLE = 4，而不是1作为参考Android的说？

and it works, so When is the "1" value used? and Why is View.INVISIBLE = 4 instead of 1 as the android reference says?

在Android的参考我可以看到隐形的属性的android值：可见性定义为1

In the android reference I can see that the value Invisible for attribute android:visibility is defined as 1

推荐答案

这是一个很好的问题，我查了Android源$ C ​​$ C（框架/基/核心/ JAVA /安卓/查看/ View.java）

This is a good question, I checked the Android source code (frameworks/base/core/java/android/view/View.java)

case com.android.internal.R.styleable.View_visibility:
    final int visibility = a.getInt(attr, 0);
    if (visibility != 0) {
          viewFlagValues |= VISIBILITY_FLAGS[visibility]; //here is the key to your question
          viewFlagMasks |= VISIBILITY_MASK;
    }
    break;

下面是VISIBILITY_FLAGS的内容：

Here is the content of VISIBILITY_FLAGS:

private static final int[] VISIBILITY_FLAGS = {VISIBLE, INVISIBLE, GONE};

数组元素的值实际上是

/**
     * This view is visible.
     * Use with {@link #setVisibility} and <a href="#attr_android:visibility">{@code
     * android:visibility}.
     */
    public static final int VISIBLE = 0x00000000;

    /**
     * This view is invisible, but it still takes up space for layout purposes.
     * Use with {@link #setVisibility} and <a href="#attr_android:visibility">{@code
     * android:visibility}.
     */
    public static final int INVISIBLE = 0x00000004;

    /**
     * This view is invisible, and it doesn't take any space for layout
     * purposes. Use with {@link #setVisibility} and <a href="#attr_android:visibility">{@code
     * android:visibility}.
     */
    public static final int GONE = 0x00000008;

因此​​，即使您使用android：在清单文件中不可见的，Android的框架将最后调用setVisibility（...）值为4。

So even if you use the android:invisible in the manifest file, Android framework will finally call setVisibility(...) with the value 4.

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