First view above / overlapping second in LinearLay

问题:

Is it possible to show the first view in a LinearLayout overlapping the second?

I would like to layout my views like so:

<LinearLayout 
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:layout_alignParentRight="true" >

    <TextView
        android:id="@+id/firstTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrapContent" />

    <TextView
        android:id="@+id/secondTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

But I need my first view from the layout, firstTextView, to be placed on top of (overlapping) secondTextView. Is this possible? I am using the LinearLayout because I'm also playing with the margins to get an overlapping effect.

回答1:

What worked for me and probably will work for you is that:

1. Wrap your 2 TextViews with RelativeLayout instead of LinearLayout and set android:clipChildren="false". This will prevent the overlapping portion from being clipped.
2. Layout the 2nd TextView below the first TextView
3. In the code, call bringToFront() on the first TextView. By default, the first textview is drawn first and will be below the second textview. Calling bringToFront() will change that order.

So the layout can be something like this:

<RelativeLayout  
xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" 
android:clipChildren="false">

<TextView
    android:id="@+id/firstTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#00000000"
    android:text="First View" />

<TextView
    android:id="@+id/secondTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@id/firstTextView"
    android:background="#00000000"
    android:layout_marginTop="-13dp"
    android:text="Second View"/>
</RelativeLayout>

and:

TextView firstTextView = (TextView)findViewById(R.id.firstTextView);
firstTextView.bringToFront();

回答2:

If all you want is to overlap the two views vertically, then use this XML:

<LinearLayout  
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/firstTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#00000000"
        android:text="First View" />

    <TextView
        android:id="@+id/secondTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#00000000"
        android:layout_marginTop="-13dp"
        android:text="Second View"/>
</LinearLayout>

回答3:

Or you can stick with Linear Layout, but place a RelativeLayout within it, as a child. You can than place your TextViews withing the RelativeLayout, so they'll inheret properties from RelativeLayout. You can then still use your LinearLayout for other views. http://developer.android.com/reference/android/widget/RelativeLayout.html

回答4:

By assigning margin value "<0" we can overlap the views. But Relative layout is preferable when we need o overlap views.