Overlapping Views in Android
Android handles transparency across views and drawables (including PNG images) natively, so the scenario you describe (a partially transparent ImageView in front of a Gallery) is certainly possible.
If you're having problems it may be related to either the layout or your image. I've replicated the layout you describe and successfully achieved the effect you're after. Here's the exact layout I used.
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gallerylayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Gallery
android:id="@+id/overview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<ImageView
android:id="@+id/navigmaske"
android:background="#0000"
android:src="@drawable/navigmask"
android:scaleType="fitXY"
android:layout_alignTop="@id/overview"
android:layout_alignBottom="@id/overview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</RelativeLayout>
Note that I've changed the parent RelativeLayout to a height and width of fill_parent as is generally what you want for a main Activity. Then I've aligned the top and bottom of the ImageView to the top and bottom of the Gallery to ensure it's centered in front of it.
I've also explicitly set the background of the ImageView to be transparent.
As for the image drawable itself, if you put the PNG file somewhere for me to look at I can use it in my project and see if it's responsible.
How to overlap layouts/views within LinearLayout?
50% linearOne 50% linearTwo
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/activity_test"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@color/colorAccent">
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@color/colorPrimary">
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_centerInParent="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#000" />
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#000" />
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#000" />
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
</LinearLayout>
</RelativeLayout>
============================================================================
70% linearOne 30% linearTwo
Just close your eyes Copy and paste
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="10"
tools:context="com.ncrypted.myapplication.MainActivity">
<LinearLayout
android:layout_weight="6"
android:id="@+id/linear1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="@color/colorAccent"
android:orientation="vertical">
</LinearLayout>
<RelativeLayout
android:layout_weight="2"
android:id="@+id/relative1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="@color/colorAccent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<View
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="@color/colorAccent"
android:layout_weight="1" />
<View
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="@color/colorPrimary"
android:layout_weight="1" />
</LinearLayout>
<LinearLayout
android:layout_centerInParent="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#000" />
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#000" />
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
android:background="#000" />
<View
android:layout_weight="1"
android:layout_width="50dp"
android:layout_height="50dp"
/>
</LinearLayout>
</RelativeLayout>
<LinearLayout
android:layout_weight="2"
android:id="@+id/linear2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="@color/colorPrimary"
android:orientation="vertical">
</LinearLayout>
</LinearLayout>
First view above / overlapping second in LinearLayout
What worked for me and probably will work for you is that:
- Wrap your 2 TextViews with RelativeLayout instead of LinearLayout and set android:clipChildren="false". This will prevent the overlapping portion from being clipped.
- Layout the 2nd TextView below the first TextView
- 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();
How to avoid view overlapping in RelativeLayout
I have changed some of your code and try to make a layout as you want.
<RelativeLayout
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"
android:orientation="vertical">
<ScrollView
android:id="@+id/scrollview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_alignParentTop="true"
android:fillViewport="true">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<!-- CONTENT NO 1 -->
<LinearLayout
android:id="@+id/linerlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_marginBottom="30dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Top aligned text1"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Top aligned text2"/>
</LinearLayout>
<!-- /CONTENT NO 1 -->
<LinearLayout
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_below="@+id/linerlayout"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="bottom aligned text1"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="bottom aligned text2"/>
<!-- CONTENT NO 2 -->
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:gravity="bottom"
android:layout_height="match_parent"
android:layout_weight="0">
</LinearLayout>
<!-- /CONTENT NO 2 -->
</LinearLayout>
</RelativeLayout>
</ScrollView>
<Button
android:layout_alignBottom="@id/scrollview"
android:text="bottom button"
android:layout_alignParentBottom="true"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
/>
</RelativeLayout>
you can also add your CONTENT NO 1 and CONTENT NO 2 UI as per your requirement
Placing/Overlapping(z-index) a view above another view in android
You can't use a LinearLayout for this, but you can use a FrameLayout. In a FrameLayout, the z-index is defined by the order in which the items are added, for example:
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/my_drawable"
android:scaleType="fitCenter"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center"
android:padding="5dp"
android:text="My Label"
/>
</FrameLayout>
In this instance, the TextView would be drawn on top of the ImageView, along the bottom center of the image.
Stop views from overlapping in ConstraintLayout
What you are missing is app:layout_constrainedWidth="true" which enforces constraints for Views with width set to wrap_content. I would chain the first two TextView with packed style and bias o 0.0 to align the chain to the left of the parent and constrain it to the third TextView on the right. The TextView on the right can stay on its own with the constraint on the right.
Example (assuming that only the left TextView will grow in size):
<?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">
<TextView
android:id="@+id/left"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="left"
app:layout_constrainedWidth="true"
app:layout_constraintHorizontal_chainStyle="packed"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="@id/middle"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="@+id/middle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="middle"
app:layout_constraintLeft_toRightOf="@id/left"
app:layout_constraintRight_toLeftOf="@id/right"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="@+id/right"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="right"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintRight_toRightOf="parent"/>
</android.support.constraint.ConstraintLayout>
Android: Overlapping two views (intentionally!)
You can use a RelativeLayout for the blue box, align your ImageView to the top-right corner, and then use negative margins to push it over the bounding box. Here's a sample illustrating the general idea:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_marginTop="-10dp"
android:layout_marginRight="-10dp"
android:src="@drawable/icon"/>
</RelativeLayout>
EDIT:
I played with this a bit more, and you have to set android:clipChildren="false" on the parent of the RelativeLayout. Here's a more complete sample:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".LoginActivity"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipChildren="false">
<RelativeLayout
android:layout_width="100dp"
android:layout_height="100dp"
android:background="#ff0000"
android:layout_margin="100dp">
<ImageView
android:src="@drawable/ic_launcher"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_marginRight="-25dp"
android:layout_marginTop="-25dp"/>
</RelativeLayout>
</LinearLayout>
How to partially overlap views within a relative layout
Views are drawn in the order they're listed in your layout, with the first one listed being the farthest away on the z-axis, the last being the closest. If you want the button on top, list it last in the layout.
<include layout="@layout/view"
android:id="@id/view"
android:layout_height="100dp"
android:layout_width="match_parent"
android:layout_alignParentBottom="true"/>
<include layout="@layout/button"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:layout_above="@+id/view"
android:layout_alignParentRight="true"
android:layout_marginRight="15dp"
android:layout_marginBottom="-50dp"/>
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