Comment rendre l'arrière-plan de l'image de textview semi transparent mais pas le texte?

Question

J'ai besoin de définir dynamiquement un fond d'image d'un textview et le rendre semi-transparent, avec du texte avec une opacité complète.

Quelque chose comme ça, mais compatible avec < 21 API.

android:backgroundTint="#80FFFFFF" 
android:backgroundTintMode="src_over" 

Lorsque j'utilise

textView.setBackgroundResource(x.getPicture()); 
textview.getBackground().setAlpha(80); 

cela fonctionne, mais plus tard, quand j'utilise la même ressource à un imageview il reste transparent même si j'utilise

imageView.setImageAlpha(255); 

ou

imageView.setAlpha((float) 1.0); 

Et cela affecte tout te xtview y compris le texte lui-même.

textView.setAlpha((float) 0.5); 

J'ai essayé tout ce que j'ai pu trouver mais je n'ai pas trouvé de solution. Qu'est-ce que je fais mal?

mise en page entier xml

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:background="@drawable/bg1"> 

<include 
    android:id="@+id/top_toolbar_details" 
    layout="@layout/toolbar" 
    android:layout_width="0dp" 
    android:layout_height="68dp" 
    app:layout_constraintTop_toTopOf="parent" 
    tools:layout_editor_absoluteX="0dp" /> 

<LinearLayout 
    android:id="@+id/ll_graphics" 
    android:layout_width="0dp" 
    android:layout_height="0dp" 
    android:layout_marginBottom="8dp" 
    android:orientation="vertical" 
    app:layout_constraintBottom_toTopOf="@+id/linearLayout" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintTop_toBottomOf="@+id/top_toolbar_details"> 

    <!--This is the imageview--> 
    <ImageView 
     android:id="@+id/iv_image" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:clickable="true" 
     android:keepScreenOn="true" 
     android:longClickable="true" 
     android:scaleType="centerInside" 
     app:layout_constraintBottom_toTopOf="@+id/linearLayout" 
     app:layout_constraintHorizontal_bias="0.0" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toBottomOf="@+id/top_toolbar_details" /> 

    <VideoView 
     android:id="@+id/vv_video" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:visibility="gone" 
     app:layout_constraintBottom_toBottomOf="@+id/iv_image" 
     app:layout_constraintBottom_toTopOf="@+id/linearLayout" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toBottomOf="@+id/top_toolbar_details" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="1.0" /> 

    <ScrollView 
     android:id="@+id/sv_scroller" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:fillViewport="true" 
     android:scrollbars="vertical"> 

     <!--This is the textview--> 
     <TextView 
      android:id="@+id/tv_description" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:maxLines="20" 
      android:paddingBottom="20dp" 
      android:paddingEnd="20dp" 
      android:paddingStart="20dp" 
      android:paddingTop="10dp" 
      android:scrollbars="vertical" 
      android:textColor="@color/black" 
      android:visibility="gone" 
      app:layout_constraintBottom_toBottomOf="@+id/iv_image" 
      app:layout_constraintBottom_toTopOf="@+id/linearLayout" 
      app:layout_constraintLeft_toLeftOf="parent" 
      app:layout_constraintRight_toRightOf="parent" 
      app:layout_constraintTop_toBottomOf="@+id/top_toolbar_details" /> 
    </ScrollView> 
</LinearLayout> 

<LinearLayout 
    android:id="@+id/linearLayout" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginBottom="5dp" 
    android:layout_marginEnd="8dp" 
    android:layout_marginStart="8dp" 
    android:layout_marginTop="5dp" 
    android:orientation="horizontal" 
    android:weightSum="1" 
    app:layout_constraintBottom_toTopOf="@+id/llImg" 
    app:layout_constraintHorizontal_bias="0.505" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent"> 

    <ImageButton 
     android:id="@+id/b_last_viewed" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:adjustViewBounds="true" 
     android:background="@drawable/circle_shape_drawable" 
     android:scaleType="fitCenter" 
     android:src="@drawable/ic_previous" 
     app:layout_constraintBottom_toTopOf="@+id/llImg" 
     app:layout_constraintHorizontal_bias="0.773" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toLeftOf="@+id/b_to_all" 
     app:layout_constraintTop_toBottomOf="@+id/vv_video" 
     app:layout_constraintVertical_bias="0.97" /> 

    <ImageButton 
     android:id="@+id/b_to_all" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_marginEnd="20dp" 
     android:layout_marginStart="20dp" 
     android:adjustViewBounds="true" 
     android:background="@drawable/circle_shape_drawable" 
     android:scaleType="fitCenter" 
     android:src="@drawable/ic_grid" 
     app:layout_constraintBottom_toTopOf="@+id/llImg" 
     app:layout_constraintTop_toBottomOf="@+id/vv_video" 
     app:layout_constraintVertical_bias="0.95" 
     tools:layout_editor_absoluteX="176dp" /> 

    <ImageButton 
     android:id="@+id/b_to_favourites" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:adjustViewBounds="true" 
     android:background="@drawable/circle_shape_drawable" 
     android:scaleType="fitCenter" 
     android:src="@drawable/ic_favourite" 
     app:layout_constraintBottom_toTopOf="@+id/llImg" 
     app:layout_constraintHorizontal_bias="0.164" 
     app:layout_constraintLeft_toRightOf="@+id/b_to_all" 
     app:layout_constraintRight_toRightOf="parent" /> 
</LinearLayout> 

<LinearLayout 
    android:id="@+id/llImg" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    app:layout_constraintBottom_toBottomOf="parent" 
    tools:layout_editor_absoluteX="0dp"> 

    <android.support.v17.leanback.widget.HorizontalGridView 
     android:id="@+id/gv_small_preview" 
     android:layout_width="wrap_content" 
     android:layout_height="80dp" 
     android:layout_marginBottom="0dp" 
     android:layout_marginTop="0dp" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintTop_toBottomOf="@+id/b_last_viewed" 
     app:layout_constraintVertical_bias="0.0" 
     tools:layout_editor_absoluteX="0dp" /> 

</LinearLayout> 
</android.support.constraint.ConstraintLayout> 

Answer 1

réaligner simplement votre mise en page

//this is your root 
<RelativeLayout> 
    //this is your background 
    //add your semi transparent for below imageView 
    <ImageView android:height="match_parent" android:witdh="match_parent"/> 

    //this is your text 
    <TextView/ > 

</RelativeLayout> 

puis programme

imageView.setImageAlpha(255); //it will not affect the textview 

ou tout simplement ajouter android:alpha en XML à imageView

Answer 2

Essayez ceci:

int myColor = Color.parseColor("#80FFFFFF"); 
Drawable backgroundColor = new ColorDrawable(myColor); 
backgroundColor.setAlpha(yourAlpha); 

textView.setBackground(backgroundColor);