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手把手教你用Android自定义饼状图

最近在项目中需要用到简单的饼形图统计,我们就没必要去找什么开源的,可以尝试自己画一下。现在将实现的过程分享给大家,有需要的朋友们可以参考借鉴,下面来一起看看吧。

照例先上效果图

通过该例子,你能学到什么:

     对Paint 深入理解,画绘制饼图,矩形,文字等

     加深对canvas的API的掌握,对自定义View掌握

下面我们分七步来完成一个简单的饼形图绘制过程。

1. 重新View的构造方法

 public PieView(Context context) { this(context, null); } public PieView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public PieView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } private void init() { mPieColorList = new ArrayList<>(); mPieValue = new ArrayList<>(); mStringList = new ArrayList<>(); mPaint = new Paint(); mMaxString = ""; mPaint.setColor(Color.BLACK); mPaint.setStrokeWidth(10);//画笔宽度 mPaint.setAntiAlias(true);//抗锯齿 }

2.绘制图形

 /** * 绘制饼图 * * @param canvas * @param amount */ private void drawPie(Canvas canvas, int amount) { mPaint.setColor(mCurrentColor); mPaint.setStyle(Paint.Style.FILL); int angle = (int) (360f * amount / mMaxValue); Log.d("angle", "drawPie: " + angle); canvas.drawArc(oval, mStartAngle, angle, true, mPaint); mStartAngle += angle; } /** * 绘制矩形 * * @param canvas */ private void drawRect(Canvas canvas) { if (mCurrentIndex == 0) { rect = new RectF(mRectMarginLeft, mPadding, mRectMarginLeft + RECT_WIDTH, mPadding + RECT_WIDTH); canvas.drawRect(rect, mPaint); } else { rect = new RectF(mRectMarginLeft, (mCurrentIndex) * TEXT_VERTICAL_PADDING + mPadding, mRectMarginLeft + RECT_WIDTH, (mCurrentIndex) * TEXT_VERTICAL_PADDING + mPadding + RECT_WIDTH); canvas.drawRect(rect, mPaint); } } /** * 绘画文字 * * @param canvas * @param text */ private void drawText(Canvas canvas, String text) { mPaint.setColor(TEXT_COLOR); if (mCurrentIndex == 0) { canvas.drawText(text, mTextMarginLeft, mPadding + TEXT_SIZE * 0.8f - 5, mPaint); } else { canvas.drawText(text, mTextMarginLeft, (mCurrentIndex) * TEXT_VERTICAL_PADDING + mPadding + TEXT_SIZE * 0.8f - 5, mPaint); } }

3.Pie 实体类

 public class Pie { public int PieColor; public int PieValue; public String PieString; public Pie(int pieValue, String pieString, int pieColor) { this.PieValue = pieValue; this.PieString = pieString; this.PieColor = pieColor; } }

4.xml引用

 

5.填充数据

 public class MainActivity extends Activity { private ArrayList pieArrayList = new ArrayList<>(); private String[] arr = {"C#", "C", "C++", "JAVA", "Javascript", "Object-C"}; private int[] pre = {20, 30, 10, 10, 10, 20}; private PieView pieView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); pieView = (PieView) findViewById(R.id.PieView); int[] pieColor = {getResources().getColor(R.color.blue), getResources().getColor(R.color.red), getResources().getColor(R.color.gray_dark), getResources().getColor(R.color.dark), getResources().getColor(R.color.colorPrimary), getResources().getColor(R.color.black_alpha_light)}; for (int i = 0; i  

6.完整的PieView

 public class PieView extends View { private Paint mPaint; //饼图和矩形的距离 private final int PIE_RECT_PADDING = getResources().getDimensionPixelSize(R.dimen.pie_rect_padding); //矩形的宽度 private final int RECT_WIDTH = getResources().getDimensionPixelSize(R.dimen.rect_width); //矩形和文字的距离 private final int RECT_TEXT_PADDING = getResources().getDimensionPixelSize(R.dimen.rect_text_padding); //文字的大小 private final int TEXT_SIZE = getResources().getDimensionPixelSize(R.dimen.text_size); //文字的垂直距离 private final int TEXT_VERTICAL_PADDING = getResources().getDimensionPixelSize(R.dimen.text_vertical_padding); //得到文字颜色 private final int TEXT_COLOR = getResources().getColor(R.color.gray_dark); //文字和控件顶部的距离 private float mPadding; //饼图的半径 private int mPieRadios; //所有数值的总和 private int mMaxValue; //饼图开始的角度 private int mStartAngle; //文字的宽度 private int mTextWidth; //控件半高 private int mControlHalfHeight; //当前索引 private int mCurrentIndex; //左边距 private int mRectMarginLeft; private int mTextMarginLeft; //当前颜色 private int mCurrentColor; //圆的范围 private RectF oval; //最长的字符串 private String mMaxString; private List mPieColorList; private List mPieValue; private List mStringList; private ArrayList mPieArrayList; private RectF rect; public PieView(Context context) { this(context, null); } public PieView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public PieView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } private void init() { mPieColorList = new ArrayList<>(); mPieValue = new ArrayList<>(); mStringList = new ArrayList<>(); mPaint = new Paint(); mMaxString = ""; mPaint.setColor(Color.BLACK); mPaint.setStrokeWidth(10);//画笔宽度 mPaint.setAntiAlias(true);//抗锯齿 } @Override protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) { super.onSizeChanged(width, height, oldWidth, oldHeight); mTextWidth = (int) mPaint.measureText(mMaxString); mCOntrolHalfHeight= height / 2; //饼图半径 mPieRadios = mControlHalfHeight - 5; //控件内容宽度 int cOntentWidth= mPieRadios * 2 + PIE_RECT_PADDING + RECT_WIDTH + RECT_TEXT_PADDING + mTextWidth; //内容的左边距 int cOntentMarginLeft= (width - contentWidth) / 2; //矩形的左边距 mRectMarginLeft = contentMarginLeft + mPieRadios * 2 + PIE_RECT_PADDING; //文字的左边距 mTextMarginLeft = mRectMarginLeft + RECT_WIDTH + RECT_TEXT_PADDING; //文字和控件顶部的距离 mPadding = height / mPieArrayList.size() * 0.8f; oval = new RectF(contentMarginLeft, mControlHalfHeight - mPieRadios, contentMarginLeft + mPieRadios * 2, mControlHalfHeight + mPieRadios); } /** * @param pieArrayList */ public void SetPie(ArrayList pieArrayList) { mPieArrayList = pieArrayList; for (Pie mPie : mPieArrayList) { mPieColorList.add(mPie.PieColor); mPieValue.add(mPie.PieValue); mStringList.add(mPie.PieString); if (mMaxString.length() > mPie.PieString.length()) mMaxString = mPie.PieString; } //使用postInvalidate可以直接在主线程中更新界面 postInvalidate(); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mStartAngle = -90; mCurrentIndex = 0; mMaxValue = 100; mPaint.setStyle(Paint.Style.FILL); for (int i = 0; i  

7.其他文件

colors.xml

 #0097a7 #e0e0e0 #666666 #3c3f41 #383838 #03a9f4 #ff4081

dimens.xml

 16dp 30dp 6dp 15dp 18sp 25dp

总结

好了,这样一个简单的饼形图绘制就算完成了。希望这篇文章的内容对各位Android开发者们能有所帮助,如果有疑问大家可以留言交流。

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