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How to set alpha value for my relative layout?

Hi, I am trying to set the alpha value for my relative layout, but, I am getting an error, how to solve this help to me .....

I have three layouts in my xml layout 1st layout using the 2nd layout for the background, used for the 3rd layout header used for the footer. I want to set the alpha value of the 2nd and 3rd layout, so I try many ways, but I do not know, please tell me how to set the alpha value

xml code:

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="fill_parent" android:layout_alignParentLeft="true" android:orientation="vertical" android:background="@drawable/blue"> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="60px" android:orientation="horizontal" android:layout_alignParentTop="true" android:background="@drawable/gradient_black" android:id="@+id/ttest"> <ImageView android:id="@+id/imageView1" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/header_text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="6dp" android:layout_toRightOf="@+id/imageView1" android:text="settings" android:textColor="@color/white" android:textSize="20sp" /> </RelativeLayout> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="55px" android:background="@drawable/gradient_black" android:gravity="bottom" android:orientation="horizontal" android:layout_alignParentBottom="true" > <ImageView android:id="@+id/imageView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="ssss" /> </RelativeLayout> </RelativeLayout>

the code:

 public class DesignActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); int width = getWindowManager().getDefaultDisplay().getWidth(); int height = getWindowManager().getDefaultDisplay().getHeight(); ImageView imgHead = (ImageView)findViewById(R.id.imageView1); ImageView imgbottom = (ImageView)findViewById(R.id.imageView2); imgbottom.setImageResource(R.drawable.back); imgbottom.setLayoutParams(new RelativeLayout.LayoutParams(width/8, height/8)); imgHead.setImageResource(R.drawable.b); imgHead.setLayoutParams(new RelativeLayout.LayoutParams(width/8, height/8)); // RelativeLayout relative = (RelativeLayout)findViewById(R.id.ttest); } }
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3 answers

try it

 AlphaAnimation alpha = new AlphaAnimation(0.5F, 0.5F); alpha.setDuration(0); // Make animation instant alpha.setFillAfter(true); // Tell it to persist after the animation ends // And then on your layout yourLayout.startAnimation(alpha);
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RelativeLayout rl; ...
rl.setAlpha (0.5f);

 <RelativeLayout android:id="@+id/rl" android:layout_width="200dp" android:layout_height="200dp" android:background="@drawable/bg" android:alpha="0.5">
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In these cases, I usually want to set the color and alpha at the same time, so I just use rl.setBackgroundColor(0xAACCCCCC); where A is the alpha value and C is the color in hexadecimal.

for example: rl.setBackgroundColor(0x88000000); for 0.5 transparent black background.

or in XML format: android:background="#88000000"

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