TQC-309 触控位置并画图

这是TQC的309题，

程序代码为自行撰写，

仅供参考。

 

主要练习用SurfaceView画图，

还有，必须使用触控取得画面位置，

再加上Runnable更新，

程序要先理解一下，

再动手写。

 

 

 

package COM.TQC.GDD03; import java.util.Random; import android.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.RectF; import android.os.Bundle; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; public class GDD03 extends Activity { MySurfaceView mySurfaceView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mySurfaceView = new MySurfaceView(this); setContentView(mySurfaceView); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); mySurfaceView.onResumeMySurfaceView(); } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); mySurfaceView.onPauseMySurfaceView(); } class MySurfaceView extends SurfaceView implements Runnable { Thread thread = null; SurfaceHolder surfaceHolder; volatile boolean running = false; private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); Random random; volatile boolean touched = false; volatile float touched_x, touched_y; public MySurfaceView(Context context) { super(context); // TODO Auto-generated constructor stub surfaceHolder = getHolder(); random = new Random(); } public void onResumeMySurfaceView(){ running = true; thread = new Thread(this); thread.start(); } public void onPauseMySurfaceView(){ boolean retry = true; running = false; while(retry){ try { thread.join(); retry = false; } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } @Override public void run() { // TODO Auto-generated method stub while(running){ if(surfaceHolder.getSurface().isValid()){ //此canvas自动更新 Canvas canvas = surfaceHolder.lockCanvas(); //... actual drawing on canvas paint.setStyle(Paint.Style.STROKE); paint.setStrokeWidth(3); int w = canvas.getWidth(); int h = canvas.getHeight(); int x = random.nextInt(w-1); int y = random.nextInt(h-1); int r = random.nextInt(255); int g = random.nextInt(255); int b = random.nextInt(255); //此paint画面设定为闪砾 //paint.setColor(0xff000000 + (r << 16) + (g << 8) + b); //此paint画面设定绿色 //paint.setColor(Color.GREEN); //此canvas绘图记录之前的图形 //canvas.drawPoint(x, y, paint); //此canvas绘图不记录之前的图形 //canvas.drawColor(Color.GREEN); if(touched) { canvas.drawColor(Color.GREEN); paint.setStrokeWidth(10); paint.setColor(Color.BLACK); canvas.drawPoint(touched_x, touched_y, paint); } surfaceHolder.unlockCanvasAndPost(canvas); } } } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub touched_x = event.getX(); touched_y = event.getY(); int action = event.getAction(); switch(action){ case MotionEvent.ACTION_DOWN: touched = true; break; case MotionEvent.ACTION_MOVE: touched = true; break; case MotionEvent.ACTION_UP: touched = false; break; case MotionEvent.ACTION_CANCEL: touched = false; break; case MotionEvent.ACTION_OUTSIDE: touched = false; break; default: } return true; //processed } } }