Android绘图应用程序崩溃

时间:2012-05-18 21:58:08

标签: java android surfaceview

我正在制作一个绘图应用,当我按下时,应用程序会随机崩溃。我无法弄清楚如何解决它,并且不知道从哪里开始。我不知道它是List还是时间,还是别的什么。这是我的代码:

package com.orangewhales.paint.views;

import java.util.ArrayList;
import java.util.List;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Paint.Style;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;

public class PaintView extends SurfaceView implements Callback {

boolean run = true;
Thread tUpdate;
public List<PaintPath> paths = new ArrayList<PaintPath>();

public Paint stroke = new Paint();

@Override
public void draw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.draw(canvas);

    canvas.drawRGB(255, 255, 255);

    for (PaintPath path : paths) {
        canvas.drawPath(path.path, path.paint);
    }
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    // TODO Auto-generated method stub
    switch(event.getAction()) {
    case MotionEvent.ACTION_DOWN:
        Path current = new Path();
        current.moveTo(event.getX(), event.getY());
        paths.add(new PaintPath(current, stroke));
        break;

    case MotionEvent.ACTION_MOVE:
        PaintPath path = paths.get(paths.size() - 1);
        path.path.lineTo(event.getX(), event.getY());
        break;
    }


    return true;
}

public PaintView(Context context, AttributeSet attrs) {
    super(context, attrs);

    stroke.setStyle(Style.STROKE);
    stroke.setColor(Color.BLACK);
    stroke.setStrokeWidth(10);

    tUpdate = new Thread() {

        public void run() {
            while (run) {
                Canvas c = getHolder().lockCanvas();
                draw(c);
                getHolder().unlockCanvasAndPost(c);

                update();

                try {
                    sleep(10);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }

    };

    getHolder().addCallback(this);
}

public void update() {
    // TODO Auto-generated method stub

}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    tUpdate.start();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    run = false;

    try {
        tUpdate.join();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

}

1 个答案:

答案 0 :(得分:1)

我有一段时间没有触及我的Android SDK。所以我将从一个问题开始。

你说当按下GUI时,应用程序会随机崩溃。在函数onTouchEvent中,首先发生哪个动作,ACTION_DOWN还是ACTION_MOVE? 我希望它定义明确,但我们不能假设。

我发现函数“PaintPath path = paths.get(paths.size() - 1)”中的代码是可疑的,因为无论如何,paths.size都可以为0。

我认为密切监视onTouchEvent函数是个好主意,可以使用调试器。如果您没有其他内容,请记录消息。

修复随机间歇性问题是工作的一部分。从中学习并享受乐趣。