自定義View分類
- 自定義View的步驟:
1.在res/values/中定義View的屬性,這裏包括字體顏色、修字體大小等
2.重寫View的構造方法,並獲取我們在res/values/中自定義的屬性
3.重寫onMesure()方法
4.重寫onDraw()方法
時鐘案例
- 1.首先創建一個JAVA類繼承於View,裏面有四個構造器,一般情況下調用前2個構造器,
- 2.進行繪製圖形操作(詳細見代碼部分)
- 3.繪製完成後爲了實現秒針、分針和時針的走動,需要不斷的向UI線程發送消息從而進行重新繪製,這就需要用到Handler向UI線程不斷髮送消息,同時不斷得到當前系統時間刷新繪圖的位置。必須要調用invalidate();方法提醒UI線程進行重新繪製
4.在佈局文件中要調用自定義View需要寫上包名+路徑,這樣纔可以被真正的調用
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<com.my.mywidget.widget.MyView
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
public class MyView extends View{
private int width;
private int heigth;
private Paint mPaintLine;
private Paint mPaintCircle;
private Paint mPaintText;
private Paint mPaintPoint;
private Calendar mCalendar;
public static final int NEED_REFRESH=0x23;
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case NEED_REFRESH:
mCalendar=Calendar.getInstance();
invalidate();//提醒UI線程重新繪製
handler.sendEmptyMessageDelayed(NEED_REFRESH,1000);//相當於迭代,每隔1s就發送一個空消息,告訴UI線程進行重繪操作
break;
}
}
};
// View有4個構造器
public MyView(Context context) {
super(context);
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
mCalendar=Calendar.getInstance();//初始化Calendar,得到當前時間
mPaintLine=new Paint();
mPaintLine.setColor(Color.BLACK);//設置顏色
mPaintLine.setAntiAlias(true);//設置抗鋸齒
mPaintLine.setStrokeWidth(10);//設置線條寬度
mPaintCircle=new Paint();
mPaintCircle.setStrokeWidth(10);//設置線條寬度
mPaintCircle.setColor(Color.BLACK);//設置顏色
mPaintCircle.setAntiAlias(true);//設置抗鋸齒
mPaintCircle.setStyle(Paint.Style.STROKE);//設置爲空心
mPaintText=new Paint();
mPaintText.setColor(Color.BLUE);//設置顏色
mPaintText.setTextAlign(Paint.Align.CENTER);//設置對齊方式
mPaintText.setAntiAlias(true);//設置抗鋸齒
mPaintText.setTextSize(30);//設置字體大小
mPaintPoint=new Paint();
mPaintPoint.setAntiAlias(true);//設置抗鋸齒
mPaintPoint.setStyle(Paint.Style.FILL);//設置爲FILL
mPaintPoint.setStrokeWidth(10);//設置寬度
mPaintPoint.setColor(Color.BLACK);//設置顏色
handler.sendEmptyMessage(NEED_REFRESH);//向Handler發送一個空消息
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width=getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec);//得到系統默認的寬度
heigth=getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec);//得到系統默認的高度
setMeasuredDimension(width,heigth);//將默認寬高設置上去
}
//onDraw是有UI線程調用,不需要做其他處理
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// canvas.drawLine(0,600,600,600,mPaintLine);
// canvas.drawCircle(300,300,100,mPaintCircle);
canvas.drawCircle(width/2,heigth/2,300,mPaintCircle);
canvas.drawCircle(width/2,heigth/2,10,mPaintPoint);
//利用for循環繪製時鐘的時刻信息
for (int i=1;i<=12;i++){
// canvas.save();和canvas.restore();需要配合使用
//先保存,然後進行旋轉,然後畫線,最後在轉到初始位置,
canvas.save();//保存當前畫布狀態
canvas.rotate(360/12*i,width/2,heigth/2);//第一參數代表旋轉角度,第二和第三個參數代表旋轉中心
canvas.drawLine(width/2,heigth/2-300,width/2,heigth/2-280,mPaintLine);//前兩個表示起始位置,第三和第四個表示末位置,最後一個表示畫筆
canvas.drawText(""+i,width/2,heigth/2-250,mPaintText);//第一個是文本內容,第二和第三個表示顯示文本位置
canvas.restore();//恢復到保存的畫布狀態
}
int minutes = mCalendar.get(Calendar.MINUTE);//得到當前時間的分鐘數
int hours = mCalendar.get(Calendar.HOUR);//得到當前時間的小時數
int second=mCalendar.get(Calendar.SECOND);//得到當前時間的秒數
canvas.save();
Float minutesDegree = minutes / 60f * 360;//得到當前分鐘數所佔的角度
canvas.rotate(minutesDegree, width / 2, heigth / 2);
canvas.drawLine(width / 2, heigth / 2 - 200, width / 2, heigth / 2 + 20, mPaintLine);
canvas.restore();
canvas.save();
Float hoursDegree = (hours * 60 + minutes) / 12f / 60 * 360;//得到當前小時數所佔的角度
canvas.rotate(hoursDegree, width / 2, heigth / 2);
canvas.drawLine(width / 2, heigth / 2 - 100, width / 2, heigth / 2 + 30, mPaintLine);
canvas.restore();
canvas.save();
Float secondDegree = second/60f*360;//得到當前小時數所佔的角度
canvas.rotate(secondDegree, width / 2, heigth / 2);
canvas.drawLine(width / 2, heigth / 2 - 240, width / 2, heigth / 2 + 40, mPaintLine);
canvas.restore();
}
}
圓形ImageView
package com.xc.xcskin.view;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;
/**
* 自定義的圓形ImageView,可以直接當組件在佈局中使用。
* @author caizhiming
*
*/
public class XCRoundImageView extends ImageView{
private Paint paint ;
public XCRoundImageView(Context context) {
this(context,null);
}
public XCRoundImageView(Context context, AttributeSet attrs) {
this(context, attrs,0);
}
public XCRoundImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
paint = new Paint();
}
/**
* 繪製圓形圖片
* @author caizhiming
*/
@Override
protected void onDraw(Canvas canvas) {
Drawable drawable = getDrawable();
if (null != drawable) {
Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
Bitmap b = getCircleBitmap(bitmap, 14);
final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight());
final Rect rectDest = new Rect(0,0,getWidth(),getHeight());
paint.reset();
canvas.drawBitmap(b, rectSrc, rectDest, paint);
} else {
super.onDraw(canvas);
}
}
/**
* 獲取圓形圖片方法
* @param bitmap
* @param pixels
* @return Bitmap
* @author caizhiming
*/
private Bitmap getCircleBitmap(Bitmap bitmap, int pixels) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
int x = bitmap.getWidth();
canvas.drawCircle(x / 2, x / 2, x / 2, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
}
完成這個自定義類後,就可以使用這個類了,就是把這個當組件在佈局中使用即可