翻页时钟java代码_Android编程基于自定义控件实现时钟功能的方法
本文實例講述了Android編程基于自定義控件實現時鐘功能的方法。分享給大家供大家參考，具體如下：
在學習安卓群英傳自定義控件章節的時候，有一個例子是繪制時鐘，在實現了書上的例子后就想看這個時鐘能不能動起來。
這里選擇延遲一秒發送消息重繪view來實現的動畫，對外提供了開啟時鐘，關閉時鐘的方法，當activity執行onResume方法的時候，執行startClock()方法，當移除view或activity執行onStop方法的時候可以執行stopClock()方法。
首先根據view的寬高來確定圓心的位置，并畫出一個圓。再通過view高度的一半減去圓的半徑，確定刻度的起始位置，選擇刻度的長度并繪制出來。然后再刻度下方繪制出數字。最終將畫布進行旋轉，時鐘總共有60個刻度，循環旋轉，每次旋轉6度即可。
最后是繪制指針，通過計算算出指針對應每個刻度的X,Y坐標并繪制直線。
代碼實現
自定義控件的代碼(ClockView.java)：
package com.example.clock;
import java.util.Calendar;
import java.util.Date;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;
public class ClockView extends View {
private Paint circlePaint, dialPaint, numberPaint;
// view 的寬高
private float mWidth, mHeight;
// 圓的半徑
private float circleRadius;
// 圓心X,Y坐標
private float circleX, circleY;
private int second, minute;
private double hour;
private Handler handler = new Handler(Looper.getMainLooper()) {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
if (msg.what == 0) {
invalidate();
}
}
};
public ClockView(Context context, AttributeSet attrs) {
super(context, attrs);
initPaint();
}
private void initPaint() {
// 刻盤圓，小時刻度，時針和分針的畫筆
circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
circlePaint.setColor(Color.BLACK);
circlePaint.setStyle(Paint.Style.STROKE);
circlePaint.setStrokeWidth(10);
// 分鐘刻度的畫筆
dialPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
dialPaint.setColor(Color.BLACK);
dialPaint.setStrokeWidth(5);
// 數字的畫筆
numberPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
numberPaint.setColor(Color.BLACK);
numberPaint.setStrokeWidth(5);
numberPaint.setTextSize(30);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mWidth = getMeasuredWidth();
mHeight = getMeasuredHeight();
if (mWidth < mHeight) {
// 圓的半徑為view的寬度的一半再減9，防止貼邊
circleRadius = mWidth / 2 - 9;
circleX = mWidth / 2;
circleY = mHeight / 2;
} else {
circleRadius = mHeight / 2 - 9;
circleX = mWidth / 2;
circleY = mHeight / 2;
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
setTimes();
drawCirclePoint(canvas);
drawCircle(canvas);
drawDial(canvas);
drawPointer(canvas);
}
/**
* 圓心
*
* @param canvas
*/
private void drawCirclePoint(Canvas canvas) {
canvas.drawCircle(circleX, circleY, 5, circlePaint);
}
private void drawCircle(Canvas canvas) {
canvas.drawCircle(circleX, circleY, circleRadius, circlePaint);
}
/**
* 畫刻度及時間
*
* @param canvas
*/
private void drawDial(Canvas canvas) {
// 時鐘用長一點的刻度，畫筆用畫圓的畫筆
Point hourStartPoint = new Point(circleX, circleY - circleRadius);
Point hourEndPoint = new Point(circleX, circleY - circleRadius + 40);
// 分鐘的刻度要稍微短一些，畫筆用畫圓的畫筆
Point startPoint2 = new Point(circleX, circleY - circleRadius);
Point endPoint2 = new Point(circleX, circleY - circleRadius + 10);
// 開始畫刻度和數字，總共60個刻度，12個時鐘刻度，被5整除畫一個時鐘刻度，被其余的為分針刻度
String clockNumber;
for (int i = 0; i < 60; i++) {
if (i % 5 == 0) {
if (i == 0) {
clockNumber = "12";
} else {
clockNumber = String.valueOf(i / 5);
}
// 時針刻度
canvas.drawLine(hourStartPoint.getX(), hourStartPoint.getY(),
hourEndPoint.getX(), hourEndPoint.getY(), circlePaint);
// 畫數字，需在時針刻度末端加30
canvas.drawText(clockNumber,
circleX - numberPaint.measureText(clockNumber) / 2,
hourEndPoint.getY() + 30, numberPaint);
} else {
// 畫分針刻度
canvas.drawLine(startPoint2.getX(), startPoint2.getY(),
endPoint2.getX(), endPoint2.getY(), circlePaint);
}
// 畫布旋轉6度
canvas.rotate(360 / 60, circleX, circleY);
}
}
/**
* 畫指針 X點坐標 cos(弧度)*r Y點坐標 sin(弧度)*r toRadians將角度轉成弧度
* 安卓坐標系與數學坐標系不同的地方是X軸是相反的，所以為了調整方向，需要將角度+270度
*
* @param canvas
*/
private void drawPointer(Canvas canvas) {
canvas.translate(circleX, circleY);
float hourX = (float) Math.cos(Math.toRadians(hour * 30 + 270))
* circleRadius * 0.5f;
float hourY = (float) Math.sin(Math.toRadians(hour * 30 + 270))
* circleRadius * 0.5f;
float minuteX = (float) Math.cos(Math.toRadians(minute * 6 + 270))
* circleRadius * 0.8f;
float minuteY = (float) Math.sin(Math.toRadians(minute * 6 + 270))
* circleRadius * 0.8f;
float secondX = (float) Math.cos(Math.toRadians(second * 6 + 270))
* circleRadius * 0.8f;
float secondY = (float) Math.sin(Math.toRadians(second * 6 + 270))
* circleRadius * 0.8f;
canvas.drawLine(0, 0, hourX, hourY, circlePaint);
canvas.drawLine(0, 0, minuteX, minuteY, circlePaint);
canvas.drawLine(0, 0, secondX, secondY, dialPaint);
// 一秒重繪一次
handler.sendEmptyMessageDelayed(0, 1000);
}
public void startClock() {
setTimes();
invalidate();
}
private void setTimes() {
Date date = new Date();
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
second = getTimes(date, Calendar.SECOND);
minute = getTimes(date, Calendar.MINUTE);
hour = getTimes(date, Calendar.HOUR) + minute / 12 * 0.2;
}
private int getTimes(Date date, int calendarField) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
return calendar.get(calendarField);
}
public void stopClock() {
handler.removeMessages(0);
}
}
Point.java：
package com.example.clock;
public class Point {
private float x;
private float y;
public Point(float x, float y) {
this.x = x;
this.y = y;
}
public float getX() {
return x;
}
public void setX(float x) {
this.x = x;
}
public float getY() {
return y;
}
public void setY(float y) {
this.y = y;
}
}
Acitivity(ClockActivity.java)：
package com.example.clock;
import android.app.Activity;
import android.os.Bundle;
public class ClockActivity extends Activity {
/** Called when the activity is first created. */
private ClockView clockView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
clockView = (ClockView) findViewById(R.id.clock);
}
@Override
protected void onResume() {
super.onResume();
clockView.startClock();
}
@Override
protected void onStop() {
super.onStop();
clockView.stopClock();
}
}
xml布局(main.xml)：
android:orientation="vertical"
android:layout_width="match_parent"
android:gravity="center"
android:layout_height="match_parent">
android:layout_width="match_parent"
android:id="@+id/clock"
android:layout_height="match_parent" />
希望本文所述對大家Android程序設計有所幫助。
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