零、前言
1.本篇原型是慕課網的教程,但
是用JavaScript實現在瀏覽器上
的,詳見
2.最近感覺安卓Canvas不比html5的canvas差,使用想復刻一下到Android上
3.本篇並不止於教程,而是以知其所以然來運用字元點陣及動效,這也是從JavaScript移植到安卓的必要條件
4.本篇會深入地分析整體思路與邏輯,為大家提供一種canvas繪製的思路,相信會給你帶來收穫。
最終效果
一、字元的點陣顯示
第一個問題是如何字元的點陣顯示,以及點陣形狀的自定義:效果如下:
1.從1
開始分析:先看一個陣列:
/**
* 用來顯示點陣的二維陣列
*/
public static final int[][] digit_test = new int[][]
{
{0, 0, 0, 1, 1, 0, 0},
{0, 1, 1, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{1, 1, 1, 1, 1, 1, 1}
};//1
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/**
* 顏色陣列
*/
public static final int[] colors = new int[]{
0xff33B5E5, 0xff0099CC, 0xffAA66CC, 0xff9933CC,
0xff99CC00, 0xff669900, 0xffFFBB33, 0xffFF8800, 0xffFF4444, 0xffCC0000};
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如果你高度散光,估計能一眼看出來些什麼,看不出來的話,看下圖:
你也許會說:暈,這麼簡單粗暴。—-沒錯,就是這麼粗暴
2.其實分析出來也不麻煩
就是二維陣列一行一行遍歷,遇到1就畫圖形,這裡是圓形,你可以自己畫任意的形狀
補充一下,這裡的1和0都是自定義的標示符
,你可以任意,但繪製的邏輯也要同步修改
private void renderDigitTest(Canvas canvas) {
for (int i = 0; i < Cons.digit_test.length; i++) {
for (int j = 0; j < Cons.digit_test[j].length; j++) {//一行一行遍歷,遇到1就畫
if (Cons.digit_test[i][j] == 1) {
canvas.save();
float rX = (j * 2 + 1) * (mRadius + 1);//第(i,j)個點圓心橫座標
float rY = (i * 2 + 1) * (mRadius + 1);//第(i,j)個點圓心縱座標
canvas.translate(rX, rY);
canvas.drawCircle(rX, rY, mRadius, mPaint);//畫圓
int color = Cons.colors[(int) (Math.random() * Cons.colors.length)];
mPaint.setColor(color);
canvas.restore();
}
}
}
}
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3.如何多個數字呢?
上古有道,道生一,一生二
,會一個自然第二個也就不遠了
既然一個二維陣列可以表示一個數,那麼用一個三維陣列再成放10個二維陣列不就表示數字了嗎!
三維陣列太長了,也沒有什麼技術含量,貼這裡影響市容,放在文尾,自行拷貝。
4.數字0~9的渲染函式:(這裡就畫五角星吧,路徑繪製可詳見Path篇)
/**
*
* @param pos 偏移量 x,y
* @param num 要顯示的數字
* @param canvas 畫布
*/
private void renderDigit(PointF pos, int num, Canvas canvas) {
for (int i = 0; i < Cons.digit[num].length; i++) {
for (int j = 0; j < Cons.digit[num][j].length; j++) {
if (Cons.digit[num][i][j] == 1) {
canvas.save();
float rX = pos.x + j * 2 * (mRadius + 1) + (mRadius + 1);//第(i,j)個點圓心橫座標
float rY = pos.y + i * 2 * (mRadius + 1) + (mRadius + 1);//第(i,j)個點圓心縱座標
canvas.translate(rX, rY);
Path path = CommonPath.nStarPath(5, mRadius, mRadius / 2);
int color = Cons.colors[(int) (Math.random() * Cons.colors.length)];
mPaint.setColor(color);
canvas.drawPath(path, mPaint);
canvas.restore();
}
}
}
}
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OnDraw()中:
canvas.save();
renderDigit( 1, canvas);
canvas.translate(150, 0);
renderDigit( 9, canvas);
canvas.translate(150, 0);
renderDigit(9, canvas);
canvas.translate(150, 0);
renderDigit(4, canvas);
canvas.restore();
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OK,第一步完成,萬事開頭難,理解之後,後面就很簡單了
二、靜態時間顯示與倒數計時:
1.靜態時間顯示
只要動態獲取時間即可,在onDraw中將時間解析成響應數字繪製出來,是不是很簡單
mCalendar = Calendar.getInstance();
int hour = mCalendar.get(Calendar.HOUR_OF_DAY);
int min = mCalendar.get(Calendar.MINUTE);
int sec = mCalendar.get(Calendar.SECOND);
canvas.save();
//繪製小時
renderDigit(hour / 10, canvas);
canvas.translate(17*mRadius, 0);
renderDigit(hour % 10, canvas);
//繪製冒號:
canvas.translate(17*mRadius, 0);
renderDigit(10, canvas);
//繪製分鐘
canvas.translate(11*mRadius, 0);
renderDigit(min / 10, canvas);
canvas.translate(17*mRadius, 0);
renderDigit(min % 10, canvas);
//繪製冒號:
canvas.translate(17*mRadius, 0);
renderDigit(10, canvas);
//繪製秒:
canvas.translate(11*mRadius, 0);
renderDigit(sec / 10, canvas);
canvas.translate(17*mRadius, 0);
renderDigit(sec % 10, canvas);
canvas.restore();
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通過Handler定時傳送訊息更新檢視:
倒數計時處理
//初始時設定截止日期
mCalendar = Calendar.getInstance();
mCalendar.set(2018, 11-1, 11, 21, 21, 21);
mDeadTime = mCalendar.getTimeInMillis();
//OnDraw中獲取之間的毫秒數,處理
mCalendar = Calendar.getInstance();
long lastSec = (mDeadTime - mCalendar.getTimeInMillis()) / 1000;//持續時間
int hour = (int) (lastSec / 3600);
int min = (int) (lastSec - hour * 3600) / 60;
int sec = (int) (lastSec % 60);
Log.d(TAG, "render: "+ hour+","+min+","+sec);
//接下來的和上面一樣
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4.重點:小球的運動
有點小複雜,簡單地畫了一個流程圖
先把小球封裝一下:
/**
* 作者:張風捷特烈<br/>
* 時間:2018/11/11 0011:6:13<br/>
* 郵箱:1981462002@qq.com<br/>
* 說明:小球封裝類
*/
public class Ball {
public float a;//加速度
public float vX;//速度X
public float vY;//速度Y
public float pX;//點位X
public float pY;//點位Y
public int color;//顏色
}
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準備工作
//成員變數
private int mRadius = 12;//半徑
private int mLimitY;//Y邊界
private final static int BALLS_VY = 15;//y方向速度
private final static int BALLS_ABS_VX = 20;//x方向速度數值
private final static float BALLS_A = 0.98f;//小球的加速度
private List<Ball> mBalls = new ArrayList<>();//小球集合
private long mDeadTime;//剩餘時間
private int mCurDeadTime;//當前剩餘時間
private Paint mPaint;
private Path mStarPath;
//初始化:init()
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setStyle(Paint.Style.FILL);
mLimitY = winSize.y - 200;
Calendar calendar = Calendar.getInstance();
calendar.set(2018, 11 - 1, 11, 21, 21, 21);
mDeadTime = calendar.getTimeInMillis();
mCurDeadTime = getLifeSec();
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1.使用ValueAnimator不斷重繪介面
ValueAnimator animator = ValueAnimator.ofFloat(0, 1);
animator.setRepeatCount(-1);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
update();
invalidate();
}
});
animator.start();
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2.小球集合的更新總函式
/**
* 小球集合的更新總函式
*/
private void update() {
addBalls();//新增小球
updateBalls();//更新小球
}
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3.新增倒數計時中改動的點
核心是:判斷當前時間是否改變,再將點位放到集合中
這是要注意我繪製小球放在繪製秒的前面,所以根據繪製小球時的畫布原點,在加入是對小球的點位進行偏移
/**
* 新增倒數計時中改動的點
*/
private void addBalls() {
int nextSec = getLifeSec();
int nextHours = nextSec / 3600;
int nextMinutes = (nextSec - nextHours * 3600) / 60;
int nextSeconds = nextSec % 60;
int curHours = mCurDeadTime / 3600;
int curMinutes = (mCurDeadTime - curHours * 3600) / 60;
int curSeconds = mCurDeadTime % 60;
if (nextSeconds != curSeconds) {//判斷當前時間是否改變,再將點位放到集合中
if ((curHours / 10) != (nextHours / 10)) {
addBalls((-17 * 5 - 11 * 2) * mRadius, curHours / 10);
}
if ((curHours % 10) != (nextHours % 10)) {
addBalls((-17 * 4 - 11 * 2) * mRadius, curHours % 10);
}
if ((curMinutes / 10) != (nextMinutes / 10)) {
addBalls((-17 * 3 - 11) * mRadius, curMinutes / 10);
}
if ((curMinutes % 10) != (nextMinutes % 10)) {
addBalls((-17 * 2 - 11) * mRadius, curMinutes % 10);
}
if ((curSeconds / 10) != (nextSeconds / 10)) {
addBalls(-17 * mRadius, curSeconds / 10);
}
if ((curSeconds % 10) != (nextSeconds % 10)) {
addBalls(0, nextSeconds % 10);
}
mCurDeadTime = nextSec;
}
}
/**
* 新增小球的核心邏輯
*
* @param offsetX x方向偏移
* @param num 改變的時間數字
*/
private void addBalls(int offsetX, int num) {
for (int i = 0; i < Cons.digit[num].length; i++) {
for (int j = 0; j < Cons.digit[num][i].length; j++) {
if (Cons.digit[num][i][j] == 1) {
Ball ball = new Ball();
ball.a = BALLS_A;
ball.vX = (float) (Math.pow(-1, Math.ceil(Math.random() * 1000)) * BALLS_ABS_VX * Math.random());
ball.vY = (float) (BALLS_VY * Math.random());
ball.pX = offsetX + j * 2 * (mRadius + 1) + (mRadius + 1);//第(i,j)個點圓心橫座標
ball.pY = i * 2 * (mRadius + 1) + (mRadius + 1);//第(i,j)個點圓心縱座標
ball.color = Cons.colors[(int) (Math.random() * Cons.colors.length)];
mBalls.add(ball);
}
}
}
}
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4.這裡是讓小球運動的核心:
更新所有球的位置—讓球運動,並且越界移除
根據速度和加速度的公式,每次重新整理的時間作為單位時間
安卓的ValueAnimator是0.167秒,由於程式碼的執行效率,會有一點偏差,大太多就會造成不流暢,即視覺卡頓
/**
* 更新所有球的位置---讓球運動
* 並且越界移除
*/
private void updateBalls() {
int minX = (-17 * 5 - 11 * 2) * mRadius;//限定x範圍最小值
int maxX = 400;//限定x範圍大值
for (Ball ball : mBalls) {
ball.pX += ball.vX;//x=xo+v*t
ball.pY += ball.vY;
ball.pY += ball.a;//v=vo+a*t
if (ball.pY >= mLimitY - mRadius) {//超過Y底線,反彈
ball.pY = mLimitY - mRadius;
ball.vY = -ball.vY * 0.99f;
}
if (ball.pX > maxX) {//超過X最大值,反彈
ball.pX = maxX - mRadius;
ball.vX = -ball.vX * 0.99f;
}
}
for (int i = 0; i < mBalls.size(); i++) {//刪除越界的點
if (mBalls.get(i).pX + mRadius < minX || mBalls.get(i).pY + mRadius < 0
|| mBalls.get(i).pX - mRadius > maxX) {
mBalls.remove(i);
}
}
}
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5.獲取倒數計時剩餘秒數
/**
* 獲取倒數計時剩餘秒數
*
* @return 倒數計時剩餘秒數
*/
private int getLifeSec() {
int life = Math.round((mDeadTime - System.currentTimeMillis()) / 1000);
life = life > 0 ? life : 0;
return life;
}
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6.繪製的方法:
和上面比就多了個畫圓球的方法,把化數字的方法抽取了一下。
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int hour = getLifeSec() / 3600;
int min = (getLifeSec() - hour * 3600) / 60;
int sec = getLifeSec() % 60;
canvas.save();
//繪製小時
drawHour(canvas, hour);
//繪製冒號:
drawDot(canvas);
//繪製分鐘
drawMin(canvas, min);
//繪製冒號:
drawDot(canvas);
//繪製秒:
drawSec(canvas, sec);
canvas.restore();
}
/**
* 繪製秒
*
* @param canvas
* @param sec
*/
private void drawSec(Canvas canvas, int sec) {
canvas.translate(11 * mRadius, 0);
drawBall(canvas);//繪製小球
renderDigit(sec / 10, canvas);
canvas.translate(17 * mRadius, 0);
renderDigit(sec % 10, canvas);
}
/**
* 繪製小球
*
* @param canvas
*/
private void drawBall(Canvas canvas) {
canvas.save();
canvas.translate(17 * mRadius, 0);
for (Ball ball : mBalls) {
mPaint.setColor(ball.color);
mPaint.setStyle(Paint.Style.FILL);
canvas.drawCircle(ball.pX, ball.pY, mRadius, mPaint);
}
canvas.restore();
}
/**
* 繪製分鐘
* @param canvas
* @param min
*/
private void drawMin(Canvas canvas, int min) {
canvas.translate(11 * mRadius, 0);
renderDigit(min / 10, canvas);
canvas.translate(17 * mRadius, 0);
renderDigit(min % 10, canvas);
}
/**
* 繪製冒號
* @param canvas
*/
private void drawDot(Canvas canvas) {
canvas.translate(17 * mRadius, 0);
renderDigit(10, canvas);
}
/**
* 繪製小時
* @param canvas
* @param hour
*/
private void drawHour(Canvas canvas, int hour) {
renderDigit(hour / 10, canvas);
canvas.translate(17 * mRadius, 0);
renderDigit(hour % 10, canvas);
}
/**
* 渲染數字
* @param num 要顯示的數字
* @param canvas 畫布
*/
private void renderDigit(int num, Canvas canvas) {
for (int i = 0; i < Cons.digit[num].length; i++) {
for (int j = 0; j < Cons.digit[num][j].length; j++) {
if (Cons.digit[num][i][j] == 1) {
canvas.save();
float rX = j * 2 * (mRadius + 1) + (mRadius + 1);//第(i,j)個點圓心橫座標
float rY = i * 2 * (mRadius + 1) + (mRadius + 1);//第(i,j)個點圓心縱座標
canvas.translate(rX, rY);
mPaint.setColor(Color.BLUE);
canvas.drawPath(mStarPath, mPaint);
canvas.restore();
}
}
}
}
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到這裡就OK了,是不是比想象中的要簡單
後記:捷文規範
1.本文成長記錄及勘誤表
專案原始碼 | 日期 | 備註 |
---|---|---|
V0.1–無 | 2018-11-11 | Android原生繪圖之炫酷倒數計時 |
2.更多關於我
筆名 | 微信 | 愛好 | |
---|---|---|---|
張風捷特烈 | 1981462002 | zdl1994328 | 語言 |
我的github | 我的簡書 | 我的CSDN | 個人網站 |
3.宣告
1—-本文由張風捷特烈原創,轉載請註明
2—-歡迎廣大程式設計愛好者共同交流
3—-個人能力有限,如有不正之處歡迎大家批評指證,必定虛心改正
4—-看到這裡,我在此感謝你的喜歡與支援
附錄、靜態常量
/**
* 作者:張風捷特烈<br/>
* 時間:2018/11/11 0011:6:02<br/>
* 郵箱:1981462002@qq.com<br/>
* 說明:常量
*/
public class Cons {
/**
* 顏色陣列
*/
public static final int[] colors = new int[]{
0xff33B5E5, 0xff0099CC, 0xffAA66CC, 0xff9933CC,
0xff99CC00, 0xff669900, 0xffFFBB33, 0xffFF8800, 0xffFF4444, 0xffCC0000};
/**
* 用來顯示點陣的三維陣列
*/
public static final int[][] digit_test = new int[][]
{
{0, 0, 0, 1, 1, 0, 0},
{0, 1, 1, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{1, 1, 1, 1, 1, 1, 1}
};//1
/**
* 用來顯示點陣的三維陣列
*/
public static final int[][][] digit = new int[][][]{
{
{0, 0, 1, 1, 1, 0, 0},
{0, 1, 1, 0, 1, 1, 0},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 0, 1, 1, 0},
{0, 0, 1, 1, 1, 0, 0}
},//0
{
{0, 0, 0, 1, 1, 0, 0},
{0, 1, 1, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{1, 1, 1, 1, 1, 1, 1}
},//1
{
{0, 1, 1, 1, 1, 1, 0},
{1, 1, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 1, 1, 0, 0, 0},
{0, 1, 1, 0, 0, 0, 0},
{1, 1, 0, 0, 0, 0, 0},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 1, 1, 1, 1, 1}
},//2
{
{1, 1, 1, 1, 1, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 1, 1, 1, 0, 0},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 1, 1, 1, 0}
},//3
{
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 1, 1, 1, 0},
{0, 0, 1, 1, 1, 1, 0},
{0, 1, 1, 0, 1, 1, 0},
{1, 1, 0, 0, 1, 1, 0},
{1, 1, 1, 1, 1, 1, 1},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 1, 1, 1, 1}
},//4
{
{1, 1, 1, 1, 1, 1, 1},
{1, 1, 0, 0, 0, 0, 0},
{1, 1, 0, 0, 0, 0, 0},
{1, 1, 1, 1, 1, 1, 0},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 1, 1, 1, 0}
},//5
{
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 1, 1, 0, 0, 0},
{0, 1, 1, 0, 0, 0, 0},
{1, 1, 0, 0, 0, 0, 0},
{1, 1, 0, 1, 1, 1, 0},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 1, 1, 1, 0}
},//6
{
{1, 1, 1, 1, 1, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 0, 1, 1, 0, 0, 0},
{0, 0, 1, 1, 0, 0, 0},
{0, 0, 1, 1, 0, 0, 0},
{0, 0, 1, 1, 0, 0, 0}
},//7
{
{0, 1, 1, 1, 1, 1, 0},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 1, 1, 1, 0},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 1, 1, 1, 0}
},//8
{
{0, 1, 1, 1, 1, 1, 0},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{1, 1, 0, 0, 0, 1, 1},
{0, 1, 1, 1, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 0, 1, 1},
{0, 0, 0, 0, 1, 1, 0},
{0, 0, 0, 1, 1, 0, 0},
{0, 1, 1, 0, 0, 0, 0}
},//9
{
{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 1, 1, 0},
{0, 1, 1, 0},
{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 1, 1, 0},
{0, 1, 1, 0},
{0, 0, 0, 0},
{0, 0, 0, 0}
}//:
};
}
複製程式碼