如何将图像保持在透明背景上？

Question

I want to acheive the following. Transparent background with white tick How do i get the white tick mark on the transparent background. i tried the following.

viewprev = mgridview.getChildAt(i - mgridview.getFirstVisiblePosition());
                viewprev.setBackgroundColor(Color.WHITE);
                viewprev.setAlpha(0.5f);

Answer 1

Try this out,

<?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"
android:layout_width="match_parent"
android:layout_height="match_parent">

<ImageView
    android:id="@+id/ivMain"
    android:layout_width="200dp"
    android:layout_height="200dp"
    android:contentDescription="@string/app_name"
    android:src="@mipmap/ic_launcher"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<FrameLayout
    android:layout_width="150dp"
    android:layout_height="150dp"
    android:background="#99676767"
    app:layout_constraintBottom_toBottomOf="@id/ivMain"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="@id/ivMain">

    <ImageView
        android:layout_width="55dp"
        android:layout_height="55dp"
        android:layout_gravity="center"
        android:contentDescription="@string/app_name"
        android:src="@drawable/vector_favorite" />
</FrameLayout>

Your tick should be in the FrameLayout which should be constrainted as in the code so its always in the middle of the ImageView . From the image I guess you're trying to create a long click to select items kind of thing. If so just set the visibility of FrameLayout to gone in xml and in LongClick event set it to visible

This is the output of above code:

You can play around with the color to achieve your desired transparency level

Answer 2

You may need to use FrameLayout.The Framelayout contains your image and an empty ImageView above it. When you need to draw a tick - just set its image into that ImageView.

Answer 3

First you need to add an ImageView to your grid item layout. Remember to insert the xml tag below the main grid image in order to appear on top. Then use match_parent as the image view width and height and assign the scaleType to center. This is your check mark view. You can add a semi transparent background to make a shade above the grid item image and the src attribute goes to the check mark.

You can also modify the image view visibility toggle hide and show of the check mark item.