Vamsi Challa Vamsi Challa - 4 months ago 20
Android Question

Android L's Ripple Effect - Touch Feedback for Buttons - Using XML

I am trying to understand how to implement the "Ripple Effect - Touch Feedback" for buttons and other views. I looked at the questions related to Ripple touch effect on SO and got some insight into it. I was able to successfully get the ripple effect using this java code.

import android.animation.ObjectAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RadialGradient;
import android.graphics.Region;
import android.graphics.Shader;
import android.support.annotation.NonNull;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.animation.AccelerateInterpolator;
import android.widget.Button;

public class MyButton extends Button {

private float mDownX;
private float mDownY;

private float mRadius;

private Paint mPaint;

public MyButton(final Context context) {
super(context);
init();
}

public MyButton(final Context context, final AttributeSet attrs) {
super(context, attrs);
init();
}

public MyButton(final Context context, final AttributeSet attrs,
final int defStyle) {
super(context, attrs, defStyle);
init();
}

private void init() {
mPaint = new Paint();
mPaint.setAlpha(100);
}

@Override
public boolean onTouchEvent(@NonNull final MotionEvent event) {
if (event.getActionMasked() == MotionEvent.ACTION_UP) {
mDownX = event.getX();
mDownY = event.getY();

ObjectAnimator animator = ObjectAnimator.ofFloat(this, "radius", 0,
getWidth() * 3.0f);
animator.setInterpolator(new AccelerateInterpolator());
animator.setDuration(400);
animator.start();
}
return super.onTouchEvent(event);
}

public void setRadius(final float radius) {
mRadius = radius;
if (mRadius > 0) {
RadialGradient radialGradient = new RadialGradient(mDownX, mDownY,
mRadius * 3, Color.TRANSPARENT, Color.BLACK,
Shader.TileMode.MIRROR);
mPaint.setShader(radialGradient);
}
invalidate();
}

private Path mPath = new Path();
private Path mPath2 = new Path();

@Override
protected void onDraw(@NonNull final Canvas canvas) {
super.onDraw(canvas);

mPath2.reset();
mPath2.addCircle(mDownX, mDownY, mRadius, Path.Direction.CW);

canvas.clipPath(mPath2);

mPath.reset();
mPath.addCircle(mDownX, mDownY, mRadius / 3, Path.Direction.CW);

canvas.clipPath(mPath, Region.Op.DIFFERENCE);

canvas.drawCircle(mDownX, mDownY, mRadius, mPaint);
}
}


But, i want to use XML approach. How do i achieve this? I have looked at this and this, but i am not yet that comfortable with styles, so i am finding it difficult to achieve the ripple effect.

I have a button with the following XML code:

<Button
android:id="@+id/button_email"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="0.50"
android:gravity="center"
android:text="@string/email" />


How do i get ripple effect for this button. If someone can guide me, I will be thankful.

[EDIT] Adding ripple.xml and background.xml, as mentioned in one of the links above. I have created a drawable-v21 folder in res and added the below files there.

ripple.xml

<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
android:color="@android:color/black" >
<item android:drawable="@drawable/background">
</item>
</ripple>


background.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<solid android:color="@android:color/darker_gray" />
</shape>


I added the ripple as background for my button, here is the xml for my button now..

<Button
android:id="@+id/button_email"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="0.50"
android:gravity="center"
android:background="@drawable/ripple"
android:text="@string/email" />


When i run the application i get a ResourceNotFoundException. Here is the logcat trace..

07-21 17:03:39.043: E/AndroidRuntime(15710): FATAL EXCEPTION: main
07-21 17:03:39.043: E/AndroidRuntime(15710): Process: com.xx.xxx, PID: 15710
07-21 17:03:39.043: E/AndroidRuntime(15710): android.view.InflateException: Binary XML file line #60: Error inflating class <unknown>
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.createView(LayoutInflater.java:620)
07-21 17:03:39.043: E/AndroidRuntime(15710): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:669)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:694)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.rInflate(LayoutInflater.java:758)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
07-21 17:03:39.043: E/AndroidRuntime(15710): at com.xx.xxx.BusinessAdapter.onCreateViewHolder(BusinessAdapter.java:106)
07-21 17:03:39.043: E/AndroidRuntime(15710): at com.xx.xxx.BusinessAdapter.onCreateViewHolder(BusinessAdapter.java:1)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:2915)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:2511)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.LinearLayoutManager$RenderState.next(LinearLayoutManager.java:1425)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:999)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:524)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:1461)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:1600)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.View.layout(View.java:14817)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewGroup.layout(ViewGroup.java:4631)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.View.layout(View.java:14817)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewGroup.layout(ViewGroup.java:4631)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.View.layout(View.java:14817)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewGroup.layout(ViewGroup.java:4631)
07-21 17:03:39.043: E/AndroidRuntime(15710): at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:374)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.View.layout(View.java:14817)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewGroup.layout(ViewGroup.java:4631)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.View.layout(View.java:14817)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewGroup.layout(ViewGroup.java:4631)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1983)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1740)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.Choreographer.doCallbacks(Choreographer.java:574)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.Choreographer.doFrame(Choreographer.java:544)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.os.Handler.handleCallback(Handler.java:733)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.os.Handler.dispatchMessage(Handler.java:95)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.os.Looper.loop(Looper.java:136)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.app.ActivityThread.main(ActivityThread.java:5001)
07-21 17:03:39.043: E/AndroidRuntime(15710): at java.lang.reflect.Method.invokeNative(Native Method)
07-21 17:03:39.043: E/AndroidRuntime(15710): at java.lang.reflect.Method.invoke(Method.java:515)
07-21 17:03:39.043: E/AndroidRuntime(15710): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
07-21 17:03:39.043: E/AndroidRuntime(15710): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
07-21 17:03:39.043: E/AndroidRuntime(15710): at dalvik.system.NativeStart.main(Native Method)
07-21 17:03:39.043: E/AndroidRuntime(15710): Caused by: java.lang.reflect.InvocationTargetException
07-21 17:03:39.043: E/AndroidRuntime(15710): at java.lang.reflect.Constructor.constructNative(Native Method)
07-21 17:03:39.043: E/AndroidRuntime(15710): at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
07-21 17:03:39.043: E/AndroidRuntime(15710): at android.view.LayoutInflater.createView(LayoutInflater.java:594)
07-21 17:03:39.043: E/AndroidRuntime(15710): ... 50 more
07-21 17:03:39.043: E/AndroidRuntime(15710): Caused by: android.content.res.Resources$NotFoundException: Resource is not a Drawable (color or path): TypedValue{t=0x1/d=0x7f020075 a=-1 r=0x

Answer

You can do something like this:

<Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:background="@drawable/ripple"

    />

Where the ripple.xml is:

<ripple xmlns:android="http://schemas.android.com/apk/res/android" 
                      android:color="?android:colorControlHighlight">
        <item android:id="@android:id/mask">
            <shape android:shape="oval">
                <solid android:color="?android:colorAccent" />
            </shape>
        </item>
 </ripple>