Android自定义控件实现饼状图

本文实现一个如图所示的控件，包括两部分，左边的饼状图和中间的两个小方块，及右边的两行文字

实现起来比较简单，只是一些绘图API的调用

核心代码在onDraw函数里边，对静态控件进行绘制即可

@Override
protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);
 
 float centreX= getWidth()/5;
 
 float centreY= getHeight()/2;
 
 float textSize=getHeight()/7;
 float width=(float)getWidth();
 float height=(float)getHeight();
 
 float halfSmallRec =((float)getHeight())*3/70;
 percent =((float) mBigBallNumber)/(mBigBallNumber + mSmallBallNumber);
 
 radius= Math.min(getWidth() * 1 / 8, getHeight() * 10 / 35);
 
 rectf=new RectF((int)(centreX-radius),(int)(centreY-radius),(int)(centreX+radius),(int)(centreY+radius));
 
 piePaint.setColor(mBigBallColor);
 
 
 
 canvas.drawArc(rectf, 270, 360 * percent, true, piePaint);
 
 piePaint.setColor(mSmallBallColor);
 
 canvas.drawArc(rectf, 270 + 360 * percent, 360 - 360 * percent, true, piePaint);
 颜色更改为大球的颜色*/
 piePaint.setColor(mBigBallColor);
 
 canvas.drawRect(width * 2 / 5 - halfSmallRec, height* 23/ 60 - halfSmallRec, width * 2 / 5 + halfSmallRec, height *23/ 60 + halfSmallRec, piePaint);
 
 piePaint.setColor(mSmallBallColor);
 
 canvas.drawRect(width * 2 / 5 - halfSmallRec, height * 37 / 60 - halfSmallRec, width * 2 / 5 + halfSmallRec, height * 37 / 60 + halfSmallRec, piePaint);
 
 textPaint.setColor(getResources().getColor(typedValue.resourceId));
 
 textPaint.setTextSize(textSize);
 
 String strBig = strBigBallName + mBigBallNumber;
 
 float textBigWidth =textPaint.measureText(strBig);
 Paint.FontMetrics fontMetrics=textPaint.getFontMetrics();
 
 canvas.drawText(strBig, width * 9 / 20 + textBigWidth / 2, height *23/ 60 - fontMetrics.top / 3, textPaint);
 
 String strSmall = strSmallBallName + mSmallBallNumber;
 
 float textUnderWidth=textPaint.measureText(strSmall);
 
 canvas.drawText(strSmall,width*9/20+textUnderWidth/2,height*37/60-fontMetrics.top/3,textPaint);
 
 textPaint.setColor(getResources().getColor(R.color.half_transparent));
 String strBigPercent =" ("+ mPercentBigBall +")";
 
 float bigPercent =textPaint.measureText(strBigPercent);
 
 canvas.drawText(strBigPercent, width * 9 / 20+ textBigWidth + bigPercent /2, height*23 / 60-fontMetrics.top*1/3, textPaint);
 
 String strSmallPercent =" ("+ mPercentSmallBall +")";
 float smallPercent =textPaint.measureText(strSmallPercent);
 canvas.drawText(strSmallPercent,width*9/20+textUnderWidth+ smallPercent /2,height*37/60-fontMetrics.top/3,textPaint);
}

Canvas 绘制文本时，使用FontMetrics对象，计算位置的坐标。参考：使用FontMetrics对象计算位置坐标

设置文字绘制以中心为起点开始绘制

textPaint.setTextAlign(Paint.Align.CENTER);

x的坐标好计算，y坐标需要按需使用FontMetrics几个属性即可

完整代码如下：

public class PieHalfView extends View {
 
 private Paint piePaint;
 
 private Paint textPaint;
 
 private float radius;
 private RectF rectf;
 
 private float percent;
 
 private int mBigBallColor, mSmallBallColor;
 
 private int mBigBallNumber;
 private int mSmallBallNumber;
 
 private String mPercentBigBall;
 private String mPercentSmallBall;
 
 private TypedValue typedValue;
 
 private String strBigBallName;
 private String strSmallBallName;
 
 public PieHalfView(Context context) {
 super(context);
 init(context);
 }
 
 public PieHalfView(Context context, AttributeSet attrs) {
 super(context, attrs);
 init(context);
 }
 
 public PieHalfView(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 init(context);
 }
 private void init(Context context) {
 
 piePaint =new Paint();
 piePaint.setAntiAlias(true);
 piePaint.setStyle(Paint.Style.FILL);
 
 textPaint=new Paint();
 textPaint.setStyle(Paint.Style.STROKE);
 textPaint.setAntiAlias(true);
 textPaint.setTextAlign(Paint.Align.CENTER);
 
 mBigBallColor = 0xFF9CCA5D;
 mSmallBallColor =0xFF5F7048;
 
 typedValue=new TypedValue();
 context.getTheme().resolveAttribute(R.attr.maintextclor,typedValue,true);
 mBigBallNumber =1;
 mSmallBallNumber =3;
 mPercentBigBall ="40%";
 mPercentSmallBall ="60%";
 strBigBallName =getResources().getString(R.string.big);
 strSmallBallName =getResources().getString(R.string.small);
 }
 
 @Override
 protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);
 
 float centreX= getWidth()/5;
 
 float centreY= getHeight()/2;
 
 float textSize=getHeight()/7;
 float width=(float)getWidth();
 float height=(float)getHeight();
 
 float halfSmallRec =((float)getHeight())*3/70;
 percent =((float) mBigBallNumber)/(mBigBallNumber + mSmallBallNumber);
 
 radius= Math.min(getWidth() * 1 / 8, getHeight() * 10 / 35);
 
 rectf=new RectF((int)(centreX-radius),(int)(centreY-radius),(int)(centreX+radius),(int)(centreY+radius));
 
 piePaint.setColor(mBigBallColor);
 
 
 
 canvas.drawArc(rectf, 270, 360 * percent, true, piePaint);
 
 piePaint.setColor(mSmallBallColor);
 
 canvas.drawArc(rectf, 270 + 360 * percent, 360 - 360 * percent, true, piePaint);
 
  piePaint.setColor(mBigBallColor);
 
 canvas.drawRect(width * 2 / 5 - halfSmallRec, height* 23/ 60 - halfSmallRec, width * 2 / 5 + halfSmallRec, height *23/ 60 + halfSmallRec, piePaint);
 
 piePaint.setColor(mSmallBallColor);
 
 canvas.drawRect(width * 2 / 5 - halfSmallRec, height * 37 / 60 - halfSmallRec, width * 2 / 5 + halfSmallRec, height * 37 / 60 + halfSmallRec, piePaint);
 
 textPaint.setColor(getResources().getColor(typedValue.resourceId));
 
 textPaint.setTextSize(textSize);
 
 String strBig = strBigBallName + mBigBallNumber;
 
 float textBigWidth =textPaint.measureText(strBig);
 Paint.FontMetrics fontMetrics=textPaint.getFontMetrics();
 
 canvas.drawText(strBig, width * 9 / 20 + textBigWidth / 2, height *23/ 60 - fontMetrics.top / 3, textPaint);
 
 String strSmall = strSmallBallName + mSmallBallNumber;
 
 float textUnderWidth=textPaint.measureText(strSmall);
 
 canvas.drawText(strSmall,width*9/20+textUnderWidth/2,height*37/60-fontMetrics.top/3,textPaint);
 
 textPaint.setColor(getResources().getColor(R.color.half_transparent));
 String strBigPercent =" ("+ mPercentBigBall +")";
 
 float bigPercent =textPaint.measureText(strBigPercent);
 
 canvas.drawText(strBigPercent, width * 9 / 20+ textBigWidth + bigPercent /2, height*23 / 60-fontMetrics.top*1/3, textPaint);
 
 String strSmallPercent =" ("+ mPercentSmallBall +")";
 float smallPercent =textPaint.measureText(strSmallPercent);
 canvas.drawText(strSmallPercent,width*9/20+textUnderWidth+ smallPercent /2,height*37/60-fontMetrics.top/3,textPaint);
 }
 public void setPercent(float percent1){
 this.percent =percent1;
 invalidate();
 }
 public void setColor(int mBigBallColor,int mSmallBallColor){
 this.mBigBallColor =mBigBallColor;
 this.mSmallBallColor =mSmallBallColor;
 invalidate();
 }
 
 public void setOverRunner(String bigPecent, String smallPercent, int big, int small,
 int bigColor, int smallColor){
 this.mPercentBigBall = bigPecent;
 this.mPercentSmallBall = smallPercent;
 this.mBigBallNumber = big;
 this.mSmallBallNumber = small;
 this.mBigBallColor = bigColor;
 this.mSmallBallColor = smallColor;
 invalidate();
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。