SurfaceView绘制音乐柱形图



SurfaceView  绘制时：先走onMeasre方法，在走SurfaceHolder.Callback的surfaceCreated（SurfaceView在创建时系统回掉方法，做一些初始化），在走surfaceDestroyed（SirfaceView在销毁时回掉的方法，在这个方法里可以做一些结束任务的操作）。

package com.sxwdsoft.widget;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.util.Log;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.WindowManager;import java.util.ArrayList;import java.util.List;import java.util.Random;public class AnalysisBarChartingView extends SurfaceView implements SurfaceHolder.Callback, Runnable {    /**     * 屏幕的大小     */    private int width, height;    /**     * view的大小     */    private int viewWidth, viewHeight;
    private SurfaceHolder holder;//这个对象可以在线程里异步操作获取的canvas对象。    private Integer[] origin;    private int lineWidth = 1;    private boolean running = false;    private int gridWidth = 40;    private int space = 20;    private String[] bgs = {"#FFD39B", "#EEB422", "#E0FFFF", "#919191"};    private int[] itemBg = {Color.BLACK, Color.BLUE, Color.DKGRAY, Color.GREEN};    public AnalysisBarChartingView(Context context) {        super(context);        init(context);    }    public AnalysisBarChartingView(Context context, AttributeSet attrs) {        super(context, attrs);        init(context);    }    public AnalysisBarChartingView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init(context);    }    private void init(Context context) {        DisplayMetrics metrics = new DisplayMetrics();        WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);        manager.getDefaultDisplay().getMetrics(metrics);        width = metrics.widthPixels;        height = metrics.heightPixels;    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        viewWidth = getDefaultSize(width, widthMeasureSpec);        viewHeight = getDefaultSize(height, heightMeasureSpec);        holder = getHolder();        holder.addCallback(this);    }    @Override    public void surfaceCreated(SurfaceHolder holder) {        origin = new Integer[]{10, (viewHeight - 10)};        Rect r = new Rect(0, 0, viewWidth, viewHeight);        Canvas canvas = holder.lockCanvas(r);        canvas.drawColor(Color.parseColor("#CFCFCF"));        Paint p = new Paint();        p.setAntiAlias(true);        p.setColor(Color.RED);        p.setStrokeWidth(lineWidth);        canvas.drawLine(origin[0], 5, origin[0], origin[1], p);        canvas.drawLine(origin[0], origin[1], viewWidth - origin[0], viewHeight - origin[0], p);        holder.unlockCanvasAndPost(canvas);        new Thread(this).start();        running = true;    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        running = false;    }    @Override    public void run() {        int num = (viewWidth - origin[0]) / (space + gridWidth);        List<Rect> rects = new ArrayList<>();        List<Paint> paints = new ArrayList<>();        int startX = origin[0], startY = origin[1], endX = origin[0], endY = origin[1];        for (int i = 0; i < num; i++) {            startX = (space * (i + 1) + gridWidth * i);            endX = ((space + gridWidth) * (i + 1));            rects.add(new Rect(startX, startY, endX, endY));            Paint paint = new Paint();            paint.setAntiAlias(true);            paint.setStyle(Paint.Style.FILL);            paint.setColor(itemBg[Math.abs(new Random().nextInt(itemBg.length))]);            paints.add(paint);        }        while (running) {            Random random = new Random();            Canvas canvas = holder.lockCanvas(new Rect(origin[0], origin[0], viewWidth - origin[0], origin[1]));            canvas.drawColor(Color.parseColor(bgs[Math.abs(new Random().nextInt(bgs.length))]));            for (int i = 0; i < num; i++) {                int y = Math.abs(random.nextInt(origin[1]));                while (y < origin[0]||y>origin[1]/2)                    y = Math.abs(random.nextInt(origin[1]));                Log.i("asd", "y=" + y);                Rect rect = rects.get(i);                rect.top = y;                canvas.drawRect(rect, paints.get(i));            }            holder.unlockCanvasAndPost(canvas);            try {                Thread.sleep(1000);            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }}