在Android开发中使用View制作一个引导动画
发布时间：2020-11-20 16:46:16
来源：亿速云
阅读：98
作者：Leah
这篇文章将为大家详细讲解有关在Android开发中使用View制作一个引导动画，文章内容质量较高，因此小编分享给大家做个参考，希望大家阅读完这篇文章后对相关知识有一定的了解。
一、实现效果图
关于贝塞尔曲线
二、实现代码
1.自定义view
package com.czhappy.showintroduce.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;
import android.widget.RelativeLayout;
/**
* Description: 水波纹动画引导view
* User: chenzheng
* Date: 2017/1/14 0014
* Time: 18:01
*/
public class RippleIntroView extends RelativeLayout implements Runnable {
private int mMaxRadius = 70;
private int mInterval = 20;
private int count = 0;
private Bitmap mCacheBitmap;
private Paint mRipplePaint;
private Paint mCirclePaint;
private Path mArcPath;
public RippleIntroView(Context context) {
this(context, null);
}
public RippleIntroView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public RippleIntroView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mRipplePaint = new Paint();
mRipplePaint.setAntiAlias(true);
mRipplePaint.setStyle(Paint.Style.STROKE);
mRipplePaint.setColor(Color.WHITE);
mRipplePaint.setStrokeWidth(2.f);
mCirclePaint = new Paint();
mCirclePaint.setAntiAlias(true);
mCirclePaint.setStyle(Paint.Style.FILL);
mCirclePaint.setColor(Color.WHITE);
mArcPath = new Path();
}
/**
* view大小变化时系统调用
* @param w
* @param h
* @param oldw
* @param oldh
*/
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
if (mCacheBitmap != null) {
mCacheBitmap.recycle();
mCacheBitmap = null;
}
}
@Override
protected void onDraw(Canvas canvas) {
//获取加号图片view
View mPlusChild = getChildAt(0);
//获取提示图片view
View mRefsChild = getChildAt(1);
if (mPlusChild == null || mRefsChild == null) return;
//获取加号图片大小
final int pw = mPlusChild.getWidth();
final int ph = mPlusChild.getHeight();
//获取提示图片大小
final int fw = mRefsChild.getWidth();
final int fh = mRefsChild.getHeight();
if (pw == 0 || ph == 0) return;
//加号图片中心点坐标
final float px = mPlusChild.getX() + pw / 2;
final float py = mPlusChild.getY() + ph / 2;
//提示图片左上角坐标
final float fx = mRefsChild.getX();
final float fy = mRefsChild.getY();
final int rw = pw / 2;
final int rh = ph / 2;
if (mCacheBitmap == null) {
mCacheBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas cv = new Canvas(mCacheBitmap);
super.onDraw(cv);
//清空所有已经画过的path至原始状态
mArcPath.reset();
//起始轮廓点移至x，y坐标点,即加号图片正下方再往下20位置
mArcPath.moveTo(px, py + rh + mInterval);
//设置二次贝塞尔，实现平滑曲线，前两个参数为操作点坐标，后两个参数为结束点坐标
mArcPath.quadTo(px, fy - mInterval, fx + fw * 0.618f, fy - mInterval);
//0~255，数值越小越透明
mRipplePaint.setAlpha(255);
cv.drawPath(mArcPath, mRipplePaint);
//绘制半径为6的实心圆点
cv.drawCircle(px, py + rh + mInterval, 6, mCirclePaint);
}
//绘制背景图片
canvas.drawBitmap(mCacheBitmap, 0, 0, mCirclePaint);
//保存画布当前的状态
int save = canvas.save();
for (int step = count; step <= mMaxRadius; step += mInterval) {
//step越大越靠外就越透明
mRipplePaint.setAlpha(255 * (mMaxRadius - step) / mMaxRadius);
canvas.drawCircle(px, py, (float) (rw + step), mRipplePaint);
}
//恢复Canvas的状态
canvas.restoreToCount(save);
//延迟80毫秒后开始运行
postDelayed(this, 80);
}
@Override
public void run() {
//把run对象的引用从队列里拿出来，这样，他就不会执行了，但 run 没有销毁
removeCallbacks(this);
count += 2;
count %= mInterval;
invalidate();//重绘
}
/**
* 销毁view时调用，收尾工作
*/
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
if (mCacheBitmap != null) {
mCacheBitmap.recycle();
mCacheBitmap = null;
}
}
}
2.MainActivity.java
package com.czhappy.showintroduce.activity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import com.czhappy.showintroduce.R;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
View view = findViewById(R.id.layout_ripple);
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
((ViewGroup) v.getParent()).removeView(v);
}
});
}
}
3.activity_main.xml
android:layout_width="match_parent"
android:layout_height="match_parent">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!" />
android:id="@+id/layout_ripple"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true"
android:fitsSystemWindows="true"
android:background="#AA000000">
android:id="@+id/iv_plus"
android:layout_marginTop="36dp"
android:src="@mipmap/ic_add"
android:layout_alignParentRight="true"
android:layout_marginRight="6dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
android:src="@mipmap/tips_subscribe"
android:id="@+id/tv_title"
android:layout_below="@id/iv_plus"
android:layout_marginTop="50dp"
android:layout_alignParentRight="true"
android:layout_marginRight="40dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
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