Android L 的涟漪效应 - 按钮的触摸反馈 - 使用 XML

Question

我正在尝试了解如何为按钮和其他 View 实现“涟漪效应 - 触摸反馈”。我查看了与 SO 上的 Ripple touch effect 相关的问题，并对它有所了解。我能够使用这个 java 代码成功地获得涟漪效应。

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);
    }
}

但是，我想使用 XML 方法。我如何实现这一目标？我看过this和 this ，但我对样式还不是很满意，所以我发现很难实现涟漪效果。

我有一个带有以下 XML 代码的按钮:

 <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" />

如何获得此按钮的涟漪效果。如果有人可以指导我，我将不胜感激。

[编辑] 添加ripple.xml 和background.xml，如上述链接之一所述。我在 res 中创建了一个 drawable-v21 文件夹，并在其中添加了以下文件。

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>

背景.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>

我添加了波纹作为按钮的背景，现在这是我的按钮的 xml..

<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" />

当我运行应用程序时，我得到一个 ResourceNotFoundException。这是 logcat 跟踪..

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 1

更新 Material 组件:

使用 Material Components Library应用波纹非常容易。
只需使用 MaterialButton和 app:rippleColor 属性:

<com.google.android.material.button.MaterialButton
    app:rippleColor="@color/my_selector"
    ../>

使用这样的选择器:

<selector xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:alpha="..." android:color="?attr/colorOnPrimary" android:state_pressed="true"/>
  <item android:alpha="..." android:color="?attr/colorOnPrimary" android:state_focused="true" android:state_hovered="true"/>
  <item android:alpha="..." android:color="?attr/colorOnPrimary" android:state_focused="true"/>
  <item android:alpha="..." android:color="?attr/colorOnPrimary" android:state_hovered="true"/>
  <item android:alpha="..." android:color="?attr/colorOnPrimary"/>

</selector>

---

旧答案
你可以这样做:

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

ripple.xml 在哪里:

<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>