Android自定义View------柱状统计图

标签：android   自定义view   

关于自定义View，相信多数开发者都已经非常熟悉了，网络上的例子也非常多，各种炫酷吊炸天的自定义View也层出不穷。本文只是一个初级学习教程，对于初学者有参考价值。

下面正式进入主题。

本文采用自定义View的方式实现柱状统计图BarGraphView，实现了柱状统计图的基本功能，因为本身是为了学习自定义View，因此扩展性比较差，只能作为自定义View的参考。

上效果图：

View显示到屏幕上主要经过这三个过程

(1)Measure（测量）

首先View需要测量自身的大小，包括长和宽。 当View类的成员函数measure决定要重新测量当前View的宽度和高度之后，会去调用另外一个成员函数onMeasure来真正执行测量宽度和高度的操作。因此，自定义View大多都需要覆写onMeasure方法来测量View的大小。onMeasure方法如下：

  @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

(2)Layout(布局)

这个过程只在View容器（ViewGroup及其子类）有用，因为非容器类View在屏幕中的位置操作由父控件来决定，所以不需要覆写onLayout()方法。

(3)Draw（绘制）

最后绘制View的过程，在这个过程里主要通过Paint对象在Canvas上面绘制相应图像，最终把View展现在屏幕上。 对于自定义View来说，通常需要覆写onDraw()方法绘制View。

    @Override
    public void onDraw(Canvas canvas) {
    }

好了，了解了上述过程，接下来我们开始实现BarGraphView。

BarGraphView主要代码集中在Draw的过程，通过onDraw方法把统计图绘制到屏幕上来。

经过分析，把柱状图分为以下几部分

1.横/纵坐标轴

2.横/纵坐标轴刻度线

3.横/纵坐标轴刻度值

4.横/纵坐标轴箭头

5.标题

6.柱状图

针对不同部分利用drawLine()(画直线)、drawText()(画文字)、drawPath()(画多边形)以及drawRect()(画矩形)的方法分别绘制相应图案。

以下是BarGraphView类代码，可以直接看注释。

package com.eleven.demo.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;

import com.eleven.demo.R;

/**
 * Created by Eleven on 2015/5/3.
 */
public class BarGraphView extends View {

    private final String TAG = BarGraphView.class.getName();
    //画笔
    private Paint mPaint;
    //标题
    private String title;
    //标题颜色
    private int titleColor;
    //标题大小
    private float titleSize;
    //X坐标轴最大值
    private float maxAxisValueX = 900;
    //X坐标轴刻度线数量
    private int axisDivideSizeX = 9;
    //Y坐标轴最大值
    private float maxAxisValueY = 700;
    //Y坐标轴刻度线数量
    private int axisDivideSizeY = 7;
    //视图宽度
    private int width;
    //视图高度
    private int height;
    //坐标原点位置
    private final int originX = 100;
    private final int originY = 800;
    //柱状图数据
    private int columnInfo[][];

    public BarGraphView(Context context, AttributeSet attrs) {
        super(context, attrs);
        //创建画笔
        mPaint = new Paint();
        //获取配置的属性值
        TypedArray mArray = context.obtainStyledAttributes(attrs, R.styleable.BarGraphView);
        title = mArray.getString(R.styleable.BarGraphView_barGraph_title);
        titleColor = mArray.getColor(R.styleable.BarGraphView_barGraph_titleColor, Color.BLACK);
        titleSize = mArray.getDimension(R.styleable.BarGraphView_barGraph_titleSize, 36);
    }

    /**
     * 设置X轴的最大值及刻度线数量（包括0坐标刻度）
     *
     * @param maxValue   X轴的最大值
     * @param divideSize 刻度线数量
     */
    public void setAxisX(float maxValue, int divideSize) {
        maxAxisValueX = maxValue;
        axisDivideSizeX = divideSize;
    }

    /**
     * 设置Y轴的最大值及刻度线数量（包括0坐标刻度）
     *
     * @param maxValue   Y轴的最大值
     * @param divideSize 刻度线数量
     */
    public void setAxisY(float maxValue, int divideSize) {
        maxAxisValueY = maxValue;
        axisDivideSizeY = divideSize;
    }

    /**
     * 设置柱状图数据
     *
     * @param columnInfo
     */
    public void setColumnInfo(int[][] columnInfo) {
        this.columnInfo = columnInfo;
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        width = MeasureSpec.getSize(widthMeasureSpec) - 200;
        height = MeasureSpec.getSize(heightMeasureSpec) - 800;
    }

    @Override
    public void onDraw(Canvas canvas) {
        drawAxisX(canvas, mPaint);
        drawAxisY(canvas, mPaint);
        drawAxisScaleMarkX(canvas, mPaint);
        drawAxisScaleMarkY(canvas, mPaint);
        drawAxisArrowsX(canvas, mPaint);
        drawAxisArrowsY(canvas, mPaint);
        drawAxisScaleMarkValueX(canvas, mPaint);
        drawAxisScaleMarkValueY(canvas, mPaint);
        drawColumn(canvas, mPaint);
        drawTitle(canvas, mPaint);
    }

    /**
     * 绘制横坐标轴（X轴）
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisX(Canvas canvas, Paint paint) {
        paint.setColor(Color.BLACK);
        //设置画笔宽度
        paint.setStrokeWidth(5);
        //设置画笔抗锯齿
        paint.setAntiAlias(true);
        //画横轴(X)
        canvas.drawLine(originX, originY, originX + width, originY, paint);
    }

    /**
     * 绘制纵坐标轴(Y轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisY(Canvas canvas, Paint paint) {
        //画竖轴(Y)
        canvas.drawLine(originX, originY, originX, originY - height, paint);//参数说明：起始点左边x,y，终点坐标x,y，画笔
    }


    /**
     * 绘制横坐标轴刻度线(X轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisScaleMarkX(Canvas canvas, Paint paint) {
        float cellWidth = width / axisDivideSizeX;
        for (int i = 0; i < axisDivideSizeX - 1; i++) {
            canvas.drawLine(cellWidth * (i + 1) + originX, originY, cellWidth * (i + 1) + originX, originY - 10, paint);
        }
    }

    /**
     * 绘制纵坐标轴刻度线(Y轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisScaleMarkY(Canvas canvas, Paint paint) {
        float cellHeight = height / axisDivideSizeY;
        for (int i = 0; i < axisDivideSizeY - 1; i++) {
            canvas.drawLine(originX, (originY - cellHeight * (i + 1)), originX + 10, (originY - cellHeight * (i + 1)), paint);
        }
    }

    /**
     * 绘制横坐标轴刻度值(X轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisScaleMarkValueX(Canvas canvas, Paint paint) {
        //设置画笔绘制文字的属性
        paint.setColor(Color.GRAY);
        paint.setTextSize(28);
        paint.setFakeBoldText(true);

        float cellWidth = width / axisDivideSizeX;
        float cellValue = maxAxisValueX / axisDivideSizeX;
        for (int i = 1; i < axisDivideSizeX; i++) {
            canvas.drawText(String.valueOf(cellValue * i), cellWidth * i + originX - 35, originY + 30, paint);
        }
    }

    /**
     * 绘制纵坐标轴刻度值(Y轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisScaleMarkValueY(Canvas canvas, Paint paint) {
        float cellHeight = height / axisDivideSizeY;
        float cellValue = maxAxisValueY / axisDivideSizeY;
        for (int i = 1; i < axisDivideSizeY; i++) {
            canvas.drawText(String.valueOf(cellValue * i), originX - 80, originY - cellHeight * i + 10, paint);
        }
    }

    /**
     * 绘制横坐标轴箭头(X轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisArrowsX(Canvas canvas, Paint paint) {
        //画三角形（X轴箭头）
        Path mPathX = new Path();
        mPathX.moveTo(originX + width + 30, originY);//起始点
        mPathX.lineTo(originX + width, originY - 10);//下一点
        mPathX.lineTo(originX + width, originY + 10);//下一点
        mPathX.close();
        canvas.drawPath(mPathX, paint);
    }

    /**
     * 绘制纵坐标轴箭头(Y轴)
     *
     * @param canvas
     * @param paint
     */
    private void drawAxisArrowsY(Canvas canvas, Paint paint) {
        //画三角形（Y轴箭头）
        Path mPathX = new Path();
        mPathX.moveTo(originX, originY - height - 30);//起始点
        mPathX.lineTo(originX - 10, originY - height);//下一点
        mPathX.lineTo(originX + 10, originY - height);//下一点
        mPathX.close();
        canvas.drawPath(mPathX, paint);
    }

    /**
     * 绘制柱状图
     *
     * @param canvas
     * @param paint
     */
    private void drawColumn(Canvas canvas, Paint paint) {
        if(columnInfo == null)
            return;
        float cellWidth = width / axisDivideSizeX;
        for (int i = 0; i < columnInfo.length; i++) {
            paint.setColor(columnInfo[i][1]);
            float leftTopY = originY - height * columnInfo[i][0] / maxAxisValueY;
            canvas.drawRect(originX + cellWidth * (i + 1), leftTopY, originX + cellWidth * (i + 2), originY, mPaint);//左上角x,y右下角x,y，画笔
        }
    }

    /**
     * 绘制标题
     *
     * @param canvas
     * @param paint
     */
    private void drawTitle(Canvas canvas, Paint paint) {

        //画标题
        if (title != null) {
            //设置画笔绘制文字的属性
            mPaint.setColor(titleColor);
            mPaint.setTextSize(titleSize);
            mPaint.setFakeBoldText(true);
            canvas.drawText(title, 300, originY + 150, paint);
        }
    }
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:eleven="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <com.eleven.demo.widget.BarGraphView
        android:id="@+id/custom_view"
        android:layout_width="600dp"
        android:layout_height="wrap_content"
        eleven:barGraph_title="自定义柱状图"
        eleven:barGraph_titleSize="24sp"
        eleven:barGraph_titleColor="@android:color/black"/>
</RelativeLayout>

public class MainActivity extends ActionBarActivity {
    private BarGraphView mBarGraphView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }

    private void initView(){
        mBarGraphView = (BarGraphView)findViewById(R.id.custom_view);
        mBarGraphView.setAxisX(900, 9);
        mBarGraphView.setAxisY(700,7);

        int columnInfo[][] = new int[][]{{600, Color.BLUE},{500, Color.GREEN},{400, Color.RED},{300, Color.BLUE},
                {500, Color.YELLOW},{300, Color.LTGRAY},{200, Color.BLUE}};
        mBarGraphView.setColumnInfo(columnInfo);
    }

该自定义View的实现中使用了自定义属性的方式定义了三个属性值，关于attrs.xml文件的使用方式参考 http://blog.csdn.net/jiangwei0910410003/article/details/17006087

Android自定义View------柱状统计图

标签：android   自定义view   

原文地址：http://blog.csdn.net/yangysng07/article/details/45459919