Android 绘制画板写字板

怼烎@ 2022-12-02 04:15 114阅读 0赞

package com.mingshine.farmmachnav.view;
    
    import android.content.Context;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.Path;
    import android.util.AttributeSet;
    import android.view.MotionEvent;
    import android.view.SurfaceHolder;
    import android.view.SurfaceView;
    
    public class MapSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Runnable { 
        private SurfaceHolder mSurfaceHolder;
        //绘图的Canvas
        private Canvas mCanvas;
        //子线程标志位
        private boolean mIsDrawing;
        //画笔
        private Paint mPaint;
        //路径
        private Path mPath;
        private static final String TAG = "pyh";
    
        public MapSurfaceView(Context context) { 
            this(context, null);
        }
    
        public MapSurfaceView(Context context, AttributeSet attrs) { 
            this(context, attrs, 0);
        }
    
        public MapSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) { 
            super(context, attrs, defStyleAttr);
            mPaint = new Paint();
            mPaint.setColor(Color.BLACK);
            mPaint.setStyle(Paint.Style.STROKE);
            mPaint.setStrokeWidth(5);
            mPaint.setAntiAlias(true);
            mPath = new Path();
            mPath.moveTo(0, 100);
            initView();
        }
    
        @Override
        public void surfaceCreated(SurfaceHolder holder) { 
            mIsDrawing = true;
            new Thread(this).start();
        }
    
        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { 
    
        }
    
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) { 
            mIsDrawing = false;
        }
    
        @Override
        public void run() { 
            while (mIsDrawing) { 
                long start = System.currentTimeMillis();
                drawSomething();
                long end = System.currentTimeMillis();
                if (end - start < 100) { 
                    try { 
                        Thread.sleep(100 - (end - start));
                    } catch (InterruptedException e) { 
                        e.printStackTrace();
                    }
                }
            }
    
        }
    
        @Override
        public boolean onTouchEvent(MotionEvent event) { 
            int x = (int) event.getX();
            int y = (int) event.getY();
            switch (event.getAction()) { 
                case MotionEvent.ACTION_DOWN:
                    mPath.moveTo(x, y);
                    break;
                case MotionEvent.ACTION_MOVE:
                    mPath.lineTo(x, y);
                    break;
                case MotionEvent.ACTION_UP:
                    break;
            }
            return true;
        }
    
        /** * 初始化View */
        private void initView() { 
            mSurfaceHolder = getHolder();
            mSurfaceHolder.addCallback(this);
            setFocusable(true);
            setKeepScreenOn(true);
            setFocusableInTouchMode(true);
        }
    
        private void drawSomething() { 
            try { 
                //获得canvas对象
                mCanvas = mSurfaceHolder.lockCanvas();
                //绘制背景
                mCanvas.drawColor(Color.WHITE);
                //绘制路径
                mCanvas.drawPath(mPath, mPaint);
            } catch (Exception e) { 
    
            } finally { 
                if (mCanvas != null) { 
                    //释放canvas对象并提交画布
                    mSurfaceHolder.unlockCanvasAndPost(mCanvas);
                }
            }
        }
    }