Android 兩種方式實現類似水波擴散效果
阿新 • • 發佈：2019-01-11
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兩種方式實現類似水波擴散效果，先上圖為敬
兩種方式實現類似水波擴散效果，先上圖為敬
- 自定義view實現
- 動畫實現
### 自定義view實現
思路分析：通過canvas畫圓，每次改變圓半徑和透明度，當半徑達到一定程度，再次從中心開始繪圓，達到不同層級的效果，通過不斷繪制達到view擴散效果
private Paint centerPaint; //中心圓paint private int radius = 100; //中心圓半徑 private Paint spreadPaint; //擴散圓paint private float centerX;//圓心x private float centerY;//圓心y private int distance = 5; //每次圓遞增間距 private int maxRadius = 80; //最大圓半徑 private int delayMilliseconds = 33;//擴散延遲間隔，越大擴散越慢 private List<Integer> spreadRadius = new ArrayList<>();//擴散圓層級數，元素為擴散的距離 private List<Integer> alphas = new ArrayList<>();//對應每層圓的透明度
style文件裏自定義屬性
<declare-styleable name="SpreadView"> <!--中心圓顏色--> <attr name="spread_center_color" format="color" /> <!--中心圓半徑--> <attr name="spread_radius" format="integer" /> <!--擴散圓顏色--> <attr name="spread_spread_color" format="color" /> <!--擴散間距--> <attr name="spread_distance" format="integer" /> <!--擴散最大半徑--> <attr name="spread_max_radius" format="integer" /> <!--擴散延遲間隔--> <attr name="spread_delay_milliseconds" format="integer" /> </declare-styleable>
初始化
public SpreadView(Context context) { this(context, null, 0); } public SpreadView(Context context, @Nullable AttributeSet attrs) { this(context, attrs, 0); } public SpreadView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SpreadView, defStyleAttr, 0); radius = a.getInt(R.styleable.SpreadView_spread_radius, radius); maxRadius = a.getInt(R.styleable.SpreadView_spread_max_radius, maxRadius); int centerColor = a.getColor(R.styleable.SpreadView_spread_center_color, ContextCompat.getColor(context, R.color.colorAccent)); int spreadColor = a.getColor(R.styleable.SpreadView_spread_spread_color, ContextCompat.getColor(context, R.color.colorAccent)); distance = a.getInt(R.styleable.SpreadView_spread_distance, distance); a.recycle(); centerPaint = new Paint(); centerPaint.setColor(centerColor); centerPaint.setAntiAlias(true); //最開始不透明且擴散距離為0 alphas.add(255); spreadRadius.add(0); spreadPaint = new Paint(); spreadPaint.setAntiAlias(true); spreadPaint.setAlpha(255); spreadPaint.setColor(spreadColor); }
確定圓心位置
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//圓心位置
centerX = w / 2;
centerY = h / 2;
}自定義view的繪制
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
for (int i = 0; i < spreadRadius.size(); i++) {
int alpha = alphas.get(i);
spreadPaint.setAlpha(alpha);
int width = spreadRadius.get(i);
//繪制擴散的圓
canvas.drawCircle(centerX, centerY, radius + width, spreadPaint);
//每次擴散圓半徑遞增，圓透明度遞減
if (alpha > 0 && width < 300) {
alpha = alpha - distance > 0 ? alpha - distance : 1;
alphas.set(i, alpha);
spreadRadius.set(i, width + distance);
}
}
//當最外層擴散圓半徑達到最大半徑時添加新擴散圓
if (spreadRadius.get(spreadRadius.size() - 1) > maxRadius) {
spreadRadius.add(0);
alphas.add(255);
}
//超過8個擴散圓，刪除最先繪制的圓，即最外層的圓
if (spreadRadius.size() >= 8) {
alphas.remove(0);
spreadRadius.remove(0);
}
//中間的圓
canvas.drawCircle(centerX, centerY, radius, centerPaint);
//TODO 可以在中間圓繪制文字或者圖片
//延遲更新，達到擴散視覺差效果
postInvalidateDelayed(delayMilliseconds);
}xml樣式
<com.airsaid.diffuseview.widget.SpreadView
android:id="@+id/spreadView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:spread_center_color="@color/colorAccent"
app:spread_delay_milliseconds="35"
app:spread_distance="5"
app:spread_max_radius="90"
app:spread_radius="100"
app:spread_spread_color="@color/colorAccent" />效果圖
中心圓處可以自定義寫文字，畫圖片等等...
動畫實現
思路分析：通過動畫實現，imageView不停做動畫縮放+漸變
最中心的imageView保持不變
中間一層imageView從原始放大到1.4倍，同時從不透明變為半透明
最外層的imageView從1.4倍放大到1.8倍，同時從半透明變為全透明
利用shape畫一個圓，作為動畫基礎視圖
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="65dp"/>
<solid android:color="@color/colorAccent"/>
</shape>布局視圖
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<!--中心imageView-->
<ImageView
android:id="@+id/iv_wave"
android:layout_width="130dp"
android:layout_height="130dp"
android:layout_gravity="center"
android:background="@drawable/shape_circle" />
<!--中間的imageView-->
<ImageView
android:id="@+id/iv_wave_1"
android:layout_width="130dp"
android:layout_height="130dp"
android:layout_gravity="center"
android:background="@drawable/shape_circle" />
<!--最外層imageView-->
<ImageView
android:id="@+id/iv_wave_2"
android:layout_width="130dp"
android:layout_height="130dp"
android:layout_gravity="center"
android:background="@drawable/shape_circle" />
</FrameLayout>中間imageView的動畫
private void setAnim1() {
AnimationSet as = new AnimationSet(true);
//縮放動畫，以中心從原始放大到1.4倍
ScaleAnimation scaleAnimation = new ScaleAnimation(1.0f, 1.4f, 1.0f, 1.4f,
ScaleAnimation.RELATIVE_TO_SELF, 0.5f,
ScaleAnimation.RELATIVE_TO_SELF, 0.5f);
//漸變動畫
AlphaAnimation alphaAnimation = new AlphaAnimation(1.0f, 0.5f);
scaleAnimation.setDuration(800);
scaleAnimation.setRepeatCount(Animation.INFINITE);
alphaAnimation.setRepeatCount(Animation.INFINITE);
as.setDuration(800);
as.addAnimation(scaleAnimation);
as.addAnimation(alphaAnimation);
iv1.startAnimation(as);
}最外層imageView的動畫
private void setAnim2() {
AnimationSet as = new AnimationSet(true);
//縮放動畫，以中心從1.4倍放大到1.8倍
ScaleAnimation scaleAnimation = new ScaleAnimation(1.4f, 1.8f, 1.4f, 1.8f,
ScaleAnimation.RELATIVE_TO_SELF, 0.5f,
ScaleAnimation.RELATIVE_TO_SELF, 0.5f);
//漸變動畫
AlphaAnimation alphaAnimation = new AlphaAnimation(0.5f, 0.1f);
scaleAnimation.setDuration(800);
scaleAnimation.setRepeatCount(Animation.INFINITE);
alphaAnimation.setRepeatCount(Animation.INFINITE);
as.setDuration(800);
as.addAnimation(scaleAnimation);
as.addAnimation(alphaAnimation);
iv2.startAnimation(as);
}效果圖
相比較而言，自定義view的效果更好點，動畫實現起來更方便點。
兩種方式實現的擴散效果介紹完畢，具體項目裏還是要按需變動的。
同時歡迎關註哈
Android 兩種方式實現類似水波擴散效果