Android自定義控件實現(xiàn)時鐘效果
在學習安卓群英傳自定義控件章節(jié)的時候,有一個例子是繪制時鐘,在實現(xiàn)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(fā)送消息重繪view來實現(xiàn)的動畫,對外提供了開啟時鐘,關閉時鐘的方法,當activity執(zhí)行onResume方法的時候,執(zhí)行startClock()方法,當移除view或activity執(zhí)行onStop方法的時候可以執(zhí)行stopClock()方法。
首先根據(jù)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(shù)字。最終將畫布進行旋轉(zhuǎn),時鐘總共有60個刻度,循環(huán)旋轉(zhuǎn),每次旋轉(zhuǎn)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(xiàn)
自定義控件的代碼:
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(shù)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(shù)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(shù)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(zhuǎn)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(zhuǎn)成弧度
* 安卓坐標系與數(shù)學坐標系不同的地方是X軸是相反的,所以為了調(diào)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);
}
}
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:
public class ClockActivity extends Activity{
private ClockView clockView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.clock_layout);
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:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:gravity="center" android:layout_height="match_parent"> <com.example.customview.view.ClockView android:layout_width="match_parent" android:id="@+id/clock" android:layout_height="match_parent" /> </LinearLayout>
以上就是本文的全部內(nèi)容,希望對大家的學習有所幫助,也希望大家多多支持腳本之家。
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