Android 自定义View-动态跳动线

View的绘制基本由measure()、layout()、draw()这个三个函数完成

函数	作用	相关方法
measure()	测量View的宽高	getMeasuredWidth(),getMeasuredHeight()
layout()	计算当前View以及子View的位置	layout(),onLayout(),setFrame()
draw()	视图的绘制工作	onDraw()

效果图如下：

代码如下：

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import java.lang.ref.WeakReference;


public class LineView extends View {
    private static final int mScaleMargin = 5; //刻度间距
    LineThread lineThread;
    private int start = 0;//起始值
    private int beforeInit = 0;//前一个初始值
    private int mWidth;//控件宽度
    private int mHeight;//控件高度

    public LineView(Context context) {
        super(context);
    }

    public LineView(Context context, AttributeSet attrs) {
        super(context, attrs);
        lineThread = new LineThread(this);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Paint paint = new Paint();
        int count = mWidth / mScaleMargin;//总刻度线，取控件一半宽度
        int midLevel = mHeight / 2;//平均高度
//        Log.i("LineView", "count: " + count + ",mid: " + midLevel);
        //算法 1 2 3 4 3 2 1 2 3 4 3 2 1
        for (int i = start; i < count + start; i++) {
            if (i % 6 == 0) {//筛选出最小值
                canvas.drawLine((i - start) * mScaleMargin, midLevel - 20, (i - start) * mScaleMargin, midLevel + 20, paint);
            } else {
                if (i % 3 == 0) {//筛选出最大值
                    canvas.drawLine((i - start) * mScaleMargin, midLevel - 80, (i - start) * mScaleMargin, midLevel + 80, paint);
                } else {
                    if (i % 2 == 0) {//筛选出第二大值
                        canvas.drawLine((i - start) * mScaleMargin, midLevel - 40, (i - start) * mScaleMargin, midLevel + 40, paint);
                    } else {
                        canvas.drawLine((i - start) * mScaleMargin, midLevel - 30, (i - start) * mScaleMargin, midLevel + 30, paint);
                    }
                }
            }
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mWidth = getMeasuredWidth();
        mHeight = getMeasuredHeight();
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
    }

    public void stopAnim() {
        if (lineThread != null) {
            lineThread.setRun(false);
            lineThread.interrupt();
            lineThread = null;
        }
    }

    public void startAnim() {
        lineThread = new LineThread(this);
        lineThread.setRun(true);
        lineThread.start();
    }

    public class LineThread extends Thread {
        private WeakReference<LineView> threadWeakReference;
        private boolean running = false;

        LineThread(LineView lineView) {
            this.threadWeakReference = new WeakReference<>(lineView);
        }

        private LineView getLieView() {
            return threadWeakReference.get();
        }

        public void setRun(boolean isRun) {
            this.running = isRun;
        }

        @Override
        public void run() {
            super.run();
            while (running) {
                try {
                    Thread.sleep(200);
                    //符合 0 1 2 3 2 1 0 算法
                    if (start == 0) {//峰谷
                        getLieView().beforeInit = start;
                        start++;
                    } else if (start == 3) {//峰顶
                        getLieView().beforeInit = start;
                        start--;
                    } else if (start == 1) {
                        if (getLieView().beforeInit > start) {
                            start--;
                        } else if (getLieView().beforeInit < start) {
                            start++;
                        }
                    } else if (start == 2) {
                        if (getLieView().beforeInit > start) {
                            start--;
                        } else if (getLieView().beforeInit < start) {
                            start++;
                        }
                    }
                    postInvalidate();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

}

本文地址：https://blog.csdn.net/xiaohelloming/article/details/107952877