在Android中将ImageView添加到RelativeLayout

Question

So I have created an ImageView programmatically in my Activity .
I want to add this ImageView at the bottom of one of my RelativeLayout .

This is what I tried:

// creating new ImageView
ImageView shadowView = new ImageView (contextPara);
shadowView.SetBackgroundResource (Resource.Drawable.bottomBar_Shadow);
shadowView.SetScaleType (ImageView.ScaleType.FitXy);

// creating ImageView LayoutParams
WindowManagerLayoutParams imgViewLayoutParams = new WindowManagerLayoutParams ();
imgViewLayoutParams.Width = ViewGroup.LayoutParams.MatchParent;
imgViewLayoutParams.Height = (int)imgViewHeight;
imgViewLayoutParams.Gravity = GravityFlags.Bottom;

// Adding ImageView to RelativeLayout
listViewRelativeLayout.AddView (shadowView, imgViewLayoutParams);

My problem is this adds the ImageView to the TOP of the RelativeLayout , NOT the bottom.

I also tried the following:
After I call the AddView and add the ImageView , I set the Y position of the ImageView .
This actually works. It moves the ImageView down but I'm not sure how much to move down. RelativeLayout size is not absolute.

// this moves the ImageView down 100px.
shadowView.SetY (100f);

How can I put it to the bottom of the RelativeLayout ?

Please note: I CAN'T just do the math ( RelativeLayout height - ImageView Height) because RelativeLayout height is always 0 until OnCreate finishes.

What are my other choices?

Thank you for your time.

Answer 1

Possible Solutions:

1.

Consider placing a single ImageView within the RelativeLayout XML.

You can access this ImageView inside the Activity/Fragment using

ImageView mImageView = (ImageView) view.findViewById(R.id.imageView);

You can set the starting visibility as gone mImageView.setVisibility(View.GONE) , and show the ImageView at a later time mImageView.setVisibility(View.VISIBLE) ;

2.

You can add a sub-layout (LinearLayout) to the existing RelativeLayout, this sub-layout can be placed at the bottom of the RelativeLayout via XML.

Inside the Activity/Fragment, you can target that sub-layout (linearLayout) by its ID, and than add the ImageView programmatically to that layout.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
             xmlns:tools="http://schemas.android.com/tools"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             tools:context="com.modup.fragment.FeedFragment">

    <!-- TODO: Update blank fragment layout -->
       <LinearLayout>
              android:id="@+id/linearLayout"
              android:layout_alignParentBottom="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
       </LinearLayout>
</RelativeLayout>

Answer 2

I found a way!

Instead of using WindowManagerLayoutParams to set LayoutParameters, using RelativeLayout.LayoutParams does the job.

Here's how:

RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams (RelativeLayout.LayoutParams.MatchParent, (int)imgViewHeight);
layoutParams.AddRule (LayoutRules.AlignParentBottom);

AlignParentBottom does the job!