本文分享了解决SurfaceView触摸轨迹闪烁问题的方法，供大家参考，具体内容如下
第一种解决SurfaceView触摸轨迹闪烁问题的方法：
由于SurfaceView使用双缓存机制，两张画布轮流显示到屏幕上。那么，要存储触摸轨迹并避免两张画布内容不一致造成的闪烁问题，完全可以利用保存绘制过程并不断重新绘制的方法解决闪烁，而且这样还顺带解决了多次试验中偶尔出现的因为moveTo（）函数不能读取到参数执行默认设置（参数设为上次的触摸点）而出现的断线连接闪烁问题，详细代码如下：
package com.tobacco.touchdraw;
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.SurfaceHolder.Callback;
import android.view.View.OnTouchListener;
public class LSurfaceView extends SurfaceView implements Callback,OnTouchListener,Runnable{
private SurfaceHolder sfh;
private Canvas canvas;
private Paint paint;
private Path path;
private ArrayList<Path> paths;
private boolean flag;
public LSurfaceView(Context context) {
super(context);
sfh=this.getHolder();
sfh.addCallback(this);
paint=new Paint();
paint.setColor(Color.RED);
paint.setAntiAlias(true);
paint.setStrokeWidth(4);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeCap(Paint.Cap.ROUND);
paths=new ArrayList<Path>();
path=new Path();
}
public void myDraw(MotionEvent e){
int action=e.getAction();
switch(action){
case MotionEvent.ACTION_DOWN:
path.moveTo(e.getX(),e.getY());
break;
case MotionEvent.ACTION_MOVE:
path.lineTo(e.getX(),e.getY());
break;
case MotionEvent.ACTION_UP:
//path.close();
Path path1=new Path(path);
paths.add(path1);
path.reset();
break;
}
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
flag=true;
setOnTouchListener(this);
new Thread(this).start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
flag=false;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
myDraw(event);
return true;
}
@Override
public void run() {
while(flag){
long start=System.currentTimeMillis();
canvas=sfh.lockCanvas();
if(canvas!=null){
canvas.drawColor(Color.BLACK);
for(int i=0;i<paths.size();i++)
canvas.drawPath(paths.get(i),paint);
canvas.drawPath(path,paint);
sfh.unlockCanvasAndPost(canvas);
}
long end=System.currentTimeMillis();
try{
if(end-start<30){
Thread.sleep(30-(end-start));
}
}
catch(Exception e){
}
}
}
}这里还要注意的是：ArrayList保存的是对象的引用，所以要在每次添加时都新建一个对象实体。
第二种解决SurfaceView触摸轨迹闪烁问题的方法：
处理触屏轨迹的绘制时，用到了SurfaceView，建立Path对象，在点击时开始设置Path对象，滑动过程中记录触摸点，离开后重新设置Path对象，因不能阻塞主线程，所以新建了一个子线程来不断刷新屏幕，也就是将path不断绘制。但是，接着就出现了一个问题：屏幕中每条轨迹线的终点都会有一小段直线段不断闪烁。猜测可能是lockCanvas（）获取的对象区域不一样，就试着使用了lockCanvas（Rect re），但是，运行后发现还是没有解决问题；接着想到可能是因为每次lockCanvas（）后获取的对象不同，就在主线程中添加了一个Canvas对象，每次都在Canvas对象中修改画面，然后提交显示，但是，程序运行后效果丝毫没有改变！程序代码如下：
package com.tobacco.touchdraw;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.SurfaceHolder.Callback;
import android.view.View.OnTouchListener;
public class MySurfaceView extends SurfaceView implements Callback,OnTouchListener,Runnable{
private SurfaceHolder sfh;
private Canvas canvas;
private Paint paint;
private float lastX,lastY;
private Path path;
private boolean flag;
public MySurfaceView(Context context) {
super(context);
sfh=this.getHolder();
sfh.addCallback(this);
paint=new Paint();
paint.setColor(Color.RED);
paint.setAntiAlias(true);
paint.setStrokeWidth(5);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeCap(Paint.Cap.ROUND);
path=new Path();
}
public void myDraw(MotionEvent e){
int action=e.getAction();
switch(action){
case MotionEvent.ACTION_DOWN:
path.moveTo(e.getX(),e.getY());
lastX=e.getX();
lastY=e.getY();
break;
case MotionEvent.ACTION_MOVE:
path.quadTo(lastX,lastY,e.getX(),e.getY());
lastX=e.getX();
lastY=e.getY();
break;
case MotionEvent.ACTION_UP:
//path.quadTo(lastX,lastY,e.getX(),e.getY());
path.reset();
break;
}
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
flag=true;
setOnTouchListener(this);
new Thread(this).start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
flag=false;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
myDraw(event);
return true;
}
@Override
public void run() {
while(flag){
long start=System.currentTimeMillis();
canvas=sfh.lockCanvas();
if(canvas!=null){
canvas.drawPath(path,paint);
sfh.unlockCanvasAndPost(canvas);
}
long end=System.currentTimeMillis();
try{
if(end-start<100){
Thread.sleep(100-(end-start));
}
}
catch(Exception e){
}
}
}
}
