i am in situation where i want to draw lines one by one with some time period. I tried to do it by using thread.but it didnt work for me. The objective is i've 5 lines. the lines should be drawn one after one with 5seconds delay .Using Thread.sleep(5000) in onDraw() method but all the lines were drawn after 5seconds those were not drawn periodically...how can i draw lines periodically...
code snippet::
public class PaintDemoActivity extends Activity {
DragView drawView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
requestWindowFeature(Window.FEATURE_NO_TITLE);
drawView = new DragView(this);
setContentView(drawView);
drawView.requestFocus();
}
}
DragView Class ::
public class DragView extends View implements OnTouchListener {
Paint paint = new Paint();
public DragView(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
paint.setColor(Color.GREEN);
paint.setStyle(Paint.Style.FILL);
//paint.setStyle(Style.STROKE);
paint.setAntiAlias(true);
}
@Override
public void onDraw(final Canvas mCanvas) {
canvas.drawCircle(p.x, p.y, 5, paint);
canvas.drawLine(60, 60, 120,60, paint);
canvas.drawLine(60, 60, 60, 120, paint);
canvas.drawLine(60, 120, 120, 120, paint);
canvas.drawLine(120, 120, 120, 180, paint);
canvas.drawLine(120, 180, 60, 180, paint);
}
}
Thanks.
Another way, a bit more generic:
public class LinesActivity extends Activity {
DemoView demoview;
int mCount = 0;
int mListSize = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Paint paint = new Paint();
paint.setColor(Color.RED);
List<Coords> coordList = new ArrayList<Coords>();
// Load up the coordinates
coordList.add(new Coords(60, 60, 120, 60));
coordList.add(new Coords(60, 60, 60, 120));
coordList.add(new Coords(60, 120, 120, 120));
coordList.add(new Coords(120, 120, 120, 180));
coordList.add(new Coords(120, 180, 60, 180));
mListSize = coordList.size();
demoview = new DemoView(this, paint, coordList);
setContentView(demoview);
Timer timer = new Timer();
timer.schedule(new TimerTask() {
public void run() {
mCount++;
demoview.postInvalidate();
Log.d("LINES", "Timer triggered");
if (mCount >= mListSize) {
Log.d("LINES", "All done, cancelling timer");
cancel();
}
}
}, 5000, 5000);
}
private class Coords {
// little class to hold the coordinates
float mSx; float mSy; float mEx; float mEy;
public Coords(float sx, float sy, float ex, float ey) {
mSx = sx; mSy = sy; // start/end x/y
mEx = ex; mEy = ey;
}
}
private class DemoView extends View {
Paint mPaint;
List<Coords> mcList;
public DemoView(Context context, Paint paint, List<Coords> cList) {
super(context);
mPaint = paint;
mcList = cList;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int count = 0;
Log.d("LINES", "mcount" + mCount);
for (Coords c : mcList) { // draw all the lines
if (count >= mCount)
break; // up to the number in mCount
canvas.drawLine(c.mSx, c.mSy, c.mEx, c.mEy, mPaint);
count++;
}
}
}
}
Ammu
try this code
final Thread thread = new Thread(new Runnable()
{
@Override
public void run()
{
synchronized (this)
{
try {
wait(500);
Main.this.runOnUiThread(new Runnable() {@Override public void run()
{
mCanvas.drawLine(60, 60, 120,60, touchPaint);
v.invalidate();
}});
wait(500);
Main.this.runOnUiThread(new Runnable() {@Override public void run()
{
mCanvas.drawLine(60, 60, 60, 120, touchPaint);
v.invalidate();
}});
wait(500);
Main.this.runOnUiThread(new Runnable() {@Override public void run()
{
mCanvas.drawLine(60, 120, 120, 120, touchPaint);
v.invalidate();
}});
wait(500);
Main.this.runOnUiThread(new Runnable() {@Override public void run()
{
mCanvas.drawLine(120, 120, 120, 180, touchPaint);
v.invalidate();
}});
wait(500);
Main.this.runOnUiThread(new Runnable() {@Override public void run()
{
mCanvas.drawLine(120, 180, 60, 180, touchPaint);
v.invalidate();
}});
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
});
thread.start();
where mCanvas is your canvas, v is your View, touchpaint is your Paint & Main.this is your activity
seems u need to use the runnable and in the runnable u have to invalidate the canvas view , ypur code seems like that .
handler.post(runnable);
int i = 0;
Runnable runnable = new Runnable() {
@Override
public void run() {
i++;
switch(i){
// do whatever yo want to do ..
}
layoutObj.removeView(your canvas View);
layoutObj.addView(your canvas View);
handler.removeCallbacks(runnable);
handler.postDelayed(runnable, 5000L);
}
};
来源：https://stackoverflow.com/questions/7130888/draw-lines-perodically