Android 在所有内容上叠加一个视图? [英] Android overlay a view ontop of everything?

问题描述

你可以在 android 中的所有内容之上叠加一个视图吗?

Can you overlay a view on top of everything in android?

在 iPhone 中，我会将新视图的 frame.origin 设置为 (0,0) 并将其宽度和高度设置为 self.view 的宽度和高度.将它添加到 self.view 将导致它充当覆盖层，覆盖后面的内容(或者如果它有透明背景，则显示后面的视图).

In iPhone I would get the new view set its frame.origin to (0,0) and its width and height to the width and height of self.view. Adding it to self.view would then cause it to act as an overlay, covering the content behind (or if it had a transparent background then showing the view behind).

android 中有类似的技术吗?我意识到视图略有不同(有三种类型(或更多......)相对布局、线性布局和框架布局)但有没有办法不加选择地将视图覆盖在所有内容之上?

Is there a similar technique in android? I realise that the views are slightly different (there are three types (or more...) relativelayout, linearlayout and framelayout) but is there any way to just overlay a view on top of everything indiscriminately?

推荐答案

只需使用 RelativeLayout 或 FrameLayout.最后一个子视图将覆盖其他所有内容.

Simply use RelativeLayout or FrameLayout. The last child view will overlay everything else.

Android 支持 Cocoa Touch SDK 不支持的模式:布局管理.
iPhone的布局意味着绝对定位所有内容(除了一些拉伸因素).android 中的布局意味着孩子将被放置在彼此相关的位置.

Android supports a pattern which Cocoa Touch SDK doesn't: Layout management.
Layout for iPhone means to position everything absolute (besides some strech factors). Layout in android means that children will be placed in relation to eachother.

示例(第二个 EditText 将完全覆盖第一个):

Example (second EditText will completely cover the first one):

<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/root_view">

    <EditText
        android:layout_width="fill_parent"
        android:id="@+id/editText1"
        android:layout_height="fill_parent">
    </EditText>

    <EditText
        android:layout_width="fill_parent"
        android:id="@+id/editText2"
        android:layout_height="fill_parent">
        <requestFocus></requestFocus>
    </EditText>

</FrameLayout>

FrameLayout 是某种视图堆栈.专为特殊情况而设计.

FrameLayout is some kind of view stack. Made for special cases.

RelativeLayout 非常强大.您可以定义规则，例如视图 A 必须对齐父布局底部，视图 B 必须将 A 底部与顶部对齐，等等

RelativeLayout is pretty powerful. You can define rules like View A has to align parent layout bottom, View B has to align A bottom to top, etc

根据评论更新

通常您在 onCreate 中使用 setContentView(R.layout.your_layout) 设置内容(它会为您扩充布局).您可以手动执行此操作并调用 setContentView(inflatedView)，没有区别.

Usually you set the content with setContentView(R.layout.your_layout) in onCreate (it will inflate the layout for you). You can do that manually and call setContentView(inflatedView), there's no difference.

视图本身可能是单个视图(如 TextView)或复杂的布局层次结构(嵌套布局，因为所有布局本身都是视图).

The view itself might be a single view (like TextView) or a complex layout hierarchy (nested layouts, since all layouts are views themselves).

调用 setContentView 后，您的 Activity 知道其内容是什么样的，您可以使用 (FrameLayout) findViewById(R.id.root_view) 检索此层次结构中的任何视图(一般模式 (ClassOfTheViewWithThisId) findViewById(R.id.declared_id_of_view)).

After calling setContentView your activity knows what its content looks like and you can use (FrameLayout) findViewById(R.id.root_view) to retrieve any view int this hierarchy (General pattern (ClassOfTheViewWithThisId) findViewById(R.id.declared_id_of_view)).

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