添加一個自定義的布局類 MaterialLayout.class
public class MaterialLayout extends RelativeLayout {
private static final int DEFAULT_RADIUS = 10;
private static final int DEFAULT_FRAME_RATE = 10;
private static final int DEFAULT_DURATION = 200;
private static final int DEFAULT_ALPHA = 255;
private static final float DEFAULT_SCALE = 0.8f;
private static final int DEFAULT_ALPHA_STEP = 5;
private int mFrameRate = DEFAULT_FRAME_RATE;
private int mDuration = DEFAULT_DURATION;
private Paint mPaint = new Paint();
private Point mCenterPoint = null;
private RectF mTargetRectf;
private int mRadius = DEFAULT_RADIUS;
private int mMaxRadius = DEFAULT_RADIUS;
private int mCirclelColor = Color.LTGRAY;
private int mRadiusStep = 1;
private int mBackupAlpha;
private float mCircleScale = DEFAULT_SCALE;
private int mColorAlpha = DEFAULT_ALPHA;
private int mAlphaStep = DEFAULT_ALPHA_STEP;
private View mTargetView;
public MaterialLayout(Context context) {
this(context, null);
}
public MaterialLayout(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs);
}
public MaterialLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context, attrs);
}
private void init(Context context, AttributeSet attrs) {
if (isInEditMode()) {
return;
}
if (attrs != null) {
initTypedArray(context, attrs);
}
initPaint();
this.setWillNotDraw(false);
this.setDrawingCacheEnabled(true);
}
private void initTypedArray(Context context, AttributeSet attrs) {
final TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.MaterialLayout);
mCirclelColor = typedArray.getColor(R.styleable.MaterialLayout_mycolor, Color.LTGRAY);
mDuration = typedArray.getInteger(R.styleable.MaterialLayout_duration, DEFAULT_DURATION);
mFrameRate = typedArray.getInteger(R.styleable.MaterialLayout_framerate, DEFAULT_FRAME_RATE);
mColorAlpha = typedArray.getInteger(R.styleable.MaterialLayout_alpha, DEFAULT_ALPHA);
mCircleScale = typedArray.getFloat(R.styleable.MaterialLayout_scale, DEFAULT_SCALE);
typedArray.recycle();
}
private void initPaint() {
mPaint.setAntiAlias(true);
mPaint.setStyle(Paint.Style.FILL);
mPaint.setColor(mCirclelColor);
mPaint.setAlpha(mColorAlpha);
// 備份alpha屬性用于動畫完成時重置
mBackupAlpha = mColorAlpha;
}
private boolean isInFrame(View touchView, float x, float y) {
initViewRect(touchView);
return mTargetRectf.contains(x, y);
}
private void initViewRect(View touchView) {
int[] location = new int[2];
touchView.getLocationOnScreen(location);
// 視圖的區域
mTargetRectf = new RectF(location[0], location[1], location[0] + touchView.getWidth(),
location[1] + touchView.getHeight());
}
private void removeExtraHeight() {
int[] location = new int[2];
this.getLocationOnScreen(location);
// 減去兩個該布局的top,這個top值就是狀态欄的高度
mTargetRectf.top -= location[1];
mTargetRectf.bottom -= location[1];
// 計算中心點坐标
int centerHorizontal = (int) (mTargetRectf.left + mTargetRectf.right) / 2;
int centerVertical = (int) ((mTargetRectf.top + mTargetRectf.bottom) / 2);
// 擷取中心點
mCenterPoint = new Point(centerHorizontal, centerVertical);
}
private View findTargetView(ViewGroup viewGroup, float x, float y) {
int childCount = viewGroup.getChildCount();
// 疊代查找被點選的目标視圖
for (int i = 0; i < childCount; i++) {
View childView = viewGroup.getChildAt(i);
if (childView instanceof ViewGroup) {
return findTargetView((ViewGroup) childView, x, y);
} else if (isInFrame(childView, x, y)) { // 否則判斷該點是否在該View的frame内
return childView;
}
}
return null;
}
private boolean isAnimEnd() {
return mRadius >= mMaxRadius;
}
private void calculateMaxRadius(View view) {
// 取視圖的最長邊
int maxLength = Math.max(view.getWidth(), view.getHeight());
// 計算Ripple圓形的半徑
mMaxRadius = (int) ((maxLength / 2) * mCircleScale);
int redrawCount = mDuration / mFrameRate;
// 計算每次動畫半徑的增值
mRadiusStep = (mMaxRadius - DEFAULT_RADIUS) / redrawCount;
// 計算每次alpha遞減的值
mAlphaStep = (mColorAlpha - 100) / redrawCount;
}
private void deliveryTouchDownEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mTargetView = findTargetView(this, event.getRawX(), event.getRawY());
if (mTargetView != null) {
removeExtraHeight();
// 計算相關資料
calculateMaxRadius(mTargetView);
// 重繪視圖
invalidate();
}
}
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
deliveryTouchDownEvent(event);
return super.onInterceptTouchEvent(event);
}
@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
// 繪制Circle
drawRippleIfNecessary(canvas);
}
private void drawRippleIfNecessary(Canvas canvas) {
if (isFoundTouchedSubView()) {
// 計算新的半徑和alpha值
mRadius += mRadiusStep;
mColorAlpha -= mAlphaStep;
// 裁剪一塊區域,這塊區域就是被點選的View的區域.通過clipRect來擷取這塊區域,使得繪制操作隻能在這個區域範圍内的進行,
// 即使繪制的内容大于這塊區域,那麼大于這塊區域的繪制内容将不可見. 這樣保證了背景層隻能繪制在被點選的視圖的區域
canvas.clipRect(mTargetRectf);
mPaint.setAlpha(mColorAlpha);
// 繪制背景圓形,也就是
canvas.drawCircle(mCenterPoint.x, mCenterPoint.y, mRadius, mPaint);
}
if (isAnimEnd()) {
reset();
} else {
invalidateDelayed();
}
}
private void invalidateDelayed() {
this.postDelayed(new Runnable() {
@Override
public void run() {
invalidate();
}
}, mFrameRate);
}
private boolean isFoundTouchedSubView() {
return mCenterPoint != null && mTargetView != null;
}
private void reset() {
mCenterPoint = null;
mTargetRectf = null;
mRadius = DEFAULT_RADIUS;
mColorAlpha = mBackupAlpha;
mTargetView = null;
invalidate();
}
}