Develop Reference

surface view not drawing anthing ... frame skipped message

public class CannonView extends SurfaceView implements SurfaceHolder.Callback {
CannonThread cannonThread;
private Paint blockerPaint;
public CannonView(Context context, AttributeSet attrs) {
super(context, attrs);
blockerPaint = new Paint();
blockerPaint.setStrokeWidth(10.0f);
getHolder().addCallback(this);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
cannonThread = new CannonThread(holder);
cannonThread.running(true);
cannonThread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
cannonThread.running(false);
while (retry) {
try {
cannonThread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
private class CannonThread extends Thread {
boolean setRunning;
SurfaceHolder surfaceHolder;
public CannonThread(SurfaceHolder holder) {
setRunning = true;
surfaceHolder = holder;
}
public void running(boolean isRunning) {
setRunning = isRunning;
}
#Override
public void run() {
Canvas canvas = null;
while (setRunning) {
try {
canvas = surfaceHolder.lockCanvas();
synchronized (surfaceHolder) {
canvas.drawLine(0, 0, 100, 100, blockerPaint);
}
} finally {
if (canvas != null)
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
}
Although above code is very simple
but it is not drawing anything on my activity ..
Logcat says i am doing too much work on main thread ..62 frame skipped ..
Please help

Well this isn't my style of coding, so I decided that you need to simplify things a bit. You used the android api guides but they suck.
Watch the following videos and you should be fine.
http://www.youtube.com/watch?v=wUmId0rwsBQ&list=SP2F07DBCDCC01493A&index=67
http://www.youtube.com/watch?v=0wy907WZFiA&list=SP2F07DBCDCC01493A
http://www.youtube.com/watch?v=ZMcYbf9Hhe4&list=SP2F07DBCDCC01493A
http://www.youtube.com/watch?v=yowNavIDzzE&list=SP2F07DBCDCC01493A

Basic surfaceView stuff - learning Android SDK

It's a bit cheeky - but I was wondering if anyone could tell me what's wrong below.
This is messing around trying to understand android - not "real" code.
It's a surfaceView which is laid out in the main activity layout.
It works - until the phone's "off" button is tapped (sleep) and woken up again. Upon waking up, it goes crazy and android produces a "Force Close" diaglog.
I've been trying to follow the path with LogCat, but for some reason, some messages get dropped - OR - the path I think is being followed, isn't.
eg - on putting the phone to sleep, I will get surfaceDestroyed called (seems reasonable) but on waking, I do not get a surfaceCreated().
The basic logic is: the surfaceView creates a thread which paints the system time in seconds as text. That's it.
I've got a real app I'd like to write - but until I really understand the basics, that won't happen. I've been through a fair number of tutorials too.
Any pointers most gratefully recieved :)
Cheers
Tim
package net.dionic.android.bouncingsquid;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.lang.System;
public class WidgetSeconds extends SurfaceView implements SurfaceHolder.Callback {
private class CanvasThread extends Thread {
private SurfaceHolder _surfaceHolder;
private WidgetSeconds _surfaceView;
private boolean _run = false;
public CanvasThread(SurfaceHolder surfaceHolder, WidgetSeconds surfaceView) {
Log.i("WidgetSecs.CanvasThread", "constructor");
_surfaceHolder = surfaceHolder;
_surfaceView = surfaceView;
}
public void setRunning(boolean run) {
_run = run;
}
#Override
public void run() {
Canvas c;
while (_run) {
c = null;
try {
c = _surfaceHolder.lockCanvas(null);
synchronized (_surfaceHolder) {
_surfaceView.onDraw(c);
try {
Thread.sleep(200);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
_surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
private CanvasThread canvasthread;
public void Initalise() {
Log.i("WidgetSecs", "Initialise");
}
public WidgetSeconds(Context context, AttributeSet attrs) {
super(context, attrs);
Log.i("WidgetSecs", "constructor");
this.Initalise();
getHolder().addCallback(this);
setFocusable(true);
}
#Override
public void onDraw(Canvas canvas) {
Paint textPaint;
canvas.drawColor(Color.GRAY);
textPaint = new Paint();
textPaint.setTextSize(32);
canvas.drawText(System.currentTimeMillis()/1000 + " S", 10, 50, textPaint);
canvas.restore();
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
Log.i("WidgetSecs", "surfaceChanged");
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
Log.i("WidgetSecs", "surfaceCreated");
Log.i("WidgetSecs.CanvasThread", "Thread create");
canvasthread = new CanvasThread(getHolder(), this);
canvasthread.setRunning(true);
canvasthread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
Log.i("WidgetSecs", "surfaceDestroyed");
boolean retry = true;
while (retry) {
try {
Log.i("WidgetSecs", "Thread destroyed");
canvasthread.join();
canvasthread = null;
retry = false;
} catch (InterruptedException e) {
Log.i("WidgetSecs", "Thread join failed");
// we will try it again and again...
}
}
}
}

ClassCastException on custom SurfaceView

i've got a big problem since a few days:
When I try to bind the surfaceview on the layout and my custom surfaceview, i get a ClassCastException from my custom surfaceview.
here is my code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
waveform =(WaveFormView) findViewById(R.id.surfaceView1);
}
class WaveFormView extends SurfaceView implements SurfaceHolder.Callback {
public WaveFormView(Context context, AttributeSet attrs) {
super(context, attrs);
getHolder().addCallback(this);
_dthread = new DrawingThread(getHolder(), this);
setFocusable(true);
paintP.setStyle(Paint.Style.STROKE);
paintP.setStrokeWidth(1);
paintP.setColor(Color.WHITE);
paintT.setStyle(Paint.Style.STROKE);
paintT.setStrokeWidth(1);
paintT.setColor(Color.WHITE);
}
#Override
public void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLACK);
for (int i=0;i<_athread.buffer.length-pas;i+=pas){
canvas.drawLine(i, 150-_athread.buffer[i], i+pas, 150-_athread.buffer[i+pas], paintP);
}
canvas.drawText("FPS: " + String.valueOf(FPS), 0, 10, paintT);
//canvas.drawText("tmp: " + tmp, 0, 20, paintT);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
_dthread.setRunning(true);
_dthread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// simply copied from sample application LunarLander:
// we have to tell thread to shut down & wait for it to finish, or else
// it might touch the Surface after we return and explode
boolean retry = true;
_dthread.setRunning(false);
while (retry) {
try {
_dthread.join();
retry = false;
} catch (InterruptedException e) {
// we will try it again and again...
}
}
}
}
class DrawingThread extends Thread {
private SurfaceHolder _surfaceHolder;
private WaveFormView _waveformview;
private boolean _run = false;
public DrawingThread(SurfaceHolder surfaceHolder, WaveFormView waveformview) {
_surfaceHolder = surfaceHolder;
_waveformview = waveformview;
}
public void setRunning(boolean run) {
_run = run;
}
public SurfaceHolder getSurfaceHolder() {
return _surfaceHolder;
}
#Override
public void run() {
Canvas c;
long startMs=System.currentTimeMillis();
int frameCounter=0;
while (_run) {
c = null;
frameCounter++;
if (System.currentTimeMillis()-startMs>1000){
startMs = System.currentTimeMillis();
FPS = frameCounter;
frameCounter=0;
}
try {
c = _surfaceHolder.lockCanvas(null);
synchronized (_surfaceHolder) {
_waveformview.onDraw(c);
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
_surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
When I replace:
setContentView(R.layout.main);
with this:
setContentView(new WaveFormView (this));
...it works perfectly !
But, I need to have buttons besides.
here is the layout:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
<LinearLayout android:layout_weight="1" android:padding="0dip" android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="vertical" android:id="#+id/content">
<TextView android:layout_height="wrap_content" android:id="#+id/tvdebug" android:text="Debug" android:layout_width="wrap_content"></TextView>
<SurfaceView android:id="#+id/surfaceView1" android:layout_height="fill_parent" android:layout_width="fill_parent"></SurfaceView>
</LinearLayout>
If someone have the solution it would me a lot !

Maybe R.id.surfaceView1 is not declared as WaveFormView but as SurfaceView? Try declare it specifically, otherwise this is illegal casting indeed.
WaveFormView is a SurfaceView, but a SurfaceView is not necessarily a WaveFormView.
You can use your own view in the layout xml, by specifying the class name (<path.to.WaveFormView instead of <SurfaceView...)
For example:
<view class = "com.mypath.WaveFormView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/surfaceView1"
android:layout_above="#id/auto_scrollview"
/>
OR
<com.mypath.WaveFormView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/surfaceView1"
android:layout_above="#id/auto_scrollview"
/>
If this class is an inner class, as seemed from your question, then use:
<com.mypath.OUTERCLASSNAME$WaveFormView
EDIT
Since this class is needed to be shown from outside your class, and be loaded not from instance but statically, you need to public static to its declaration, e.g.:
public static class WaveFormView extends SurfaceView implements SurfaceHolder.Callback

Android SurfaceView not showing onDraw

For simpleness of the question, I'm drawing an integer on a SurfaceView which increases by 1 every draw.
The increasing actually happens, as I can see on the System.out.
The text on the screen stays on '0'.
Who can tell me what I'm doing wrong?
SurfaceViewTest.java
package com.niek.surfaceviewtest;
import android.app.Activity;
import android.os.Bundle;
public class SurfaceViewTest extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
StatusView.java
package com.niek.surfaceviewtest;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class StatusView extends SurfaceView implements SurfaceHolder.Callback {
private int tmp;
private DrawThread drawThread;
public StatusView(Context context, AttributeSet attrs) {
super(context, attrs);
getHolder().addCallback(this);
setFocusable(true);
drawThread = new DrawThread(getHolder());
}
#Override
public void onDraw(Canvas c) {
c.drawColor(Color.BLACK);
Paint p = new Paint();
p.setColor(Color.RED);
c.drawText(tmp + "", 10, 10, p);
tmp++;
System.out.println(tmp);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// TODO Auto-generated method stub
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
drawThread.setRunning(true);
drawThread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// we have to tell thread to shut down & wait for it to finish, or else
// it might touch the Surface after we return and explode
boolean retry = true;
drawThread.setRunning(false);
while (retry) {
try {
drawThread.join();
retry = false;
} catch (InterruptedException e) {
// we will try it again and again...
}
}
}
protected class DrawThread extends Thread {
private SurfaceHolder surfaceHolder;
private boolean isRunning;
public DrawThread(SurfaceHolder surfaceHolder) {
this.surfaceHolder = surfaceHolder;
isRunning = false;
}
public void setRunning(boolean run) {
isRunning = run;
}
public void run() {
Canvas c;
while (isRunning) {
c = null;
try {
c = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
onDraw(c);
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFFFFF">
<com.niek.surfaceviewtest.StatusView
android:id="#+id/statusview1"
android:layout_width="fill_parent"
android:layout_height="30dip"
android:background="#000000"
/>
</LinearLayout>

My only guess is that painting isn't being done on the surface because the view isn't invalidated. You're supposed to call invalidate() in order to draw, and then let the framework call onDraw(). Maybe that's why tmp is being incremented, but the paint operation only reaches the surface the first time.
It might be worth experimenting: maybe make Canvas c a member of StatusView, and then replace
synchronized (surfaceHolder) {
onDraw(c);
}
with
synchronized (surfaceHolder) {
invalidate();
}
Does that work?

The current solution is not right. You are using the SurfaceView in order to update the content from a separate thread and not using the invalidate() method that will run onDraw() method when the system refreshes the content. The problem is that you have set a background for your StatusView, try deleting that line
android:background="#000000"
apparently, you need to control the whole information displayed in that view.

Looks like you are showing your main.xml with setContentView(R.layout.main); instead of creating the surface and displaying that. unless i am missing code somewhere I don't see that as being the case.

Application error when drawing to SurfaceView

I'm am doing a simple coding attempt trying to draw on a SurfaceView created on my main.xml layout. I can change background color and display an icon fine, but when I try to draw I get an error. I am a newbie so obvious I am missing something, please lend a helping hint, thanks!
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/root" android:orientation="vertical"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<SurfaceView android:id="#+id/Paper"
android:layout_height="fill_parent"
android:layout_width="fill_parent">
</SurfaceView>
</LinearLayout>
and code here;
package com.example.SurfaceViewTest;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class SurfaceViewTest extends Activity implements SurfaceHolder.Callback {
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
private Paint paint;
Bitmap mDrawing;
boolean mRun;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSurfaceView = (SurfaceView) this.findViewById(R.id.Paper);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_NORMAL);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// TODO Auto-generated method stub
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
mSurfaceView.setBackgroundColor(Color.rgb(0, 255, 0));
mRun=true;
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
Thread thread = new Thread(){
public void doDraw(Canvas c){
mDrawing = Bitmap.createBitmap(200, 300, Bitmap.Config.RGB_565);
c.setBitmap(mDrawing);
paint = new Paint();
paint.setColor(Color.rgb(255, 255,255));
c.drawLine(1,1,200,300, paint);
}
public void run() {
while (mRun) {
Canvas c = null;
try {
c = mSurfaceHolder.lockCanvas(null);
synchronized (mSurfaceHolder) {
doDraw(c);
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
mSurfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
};
}
UPDATE:
Ok I got it to works thanks!
package com.example.SurfaceViewTest;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class SurfaceViewTest extends Activity implements SurfaceHolder.Callback {
private SurfaceView mSurfaceView;
private SurfaceHolder mSurfaceHolder;
Bitmap mDrawing;
Canvas tempCanvas = new Canvas();
Paint paint;
boolean mRun;
int intCanvasWidth, intCanvasHeight;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSurfaceView = (SurfaceView) this.findViewById(R.id.Paper);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_NORMAL);
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
intCanvasWidth = width;
intCanvasHeight = height;
mDrawing = Bitmap.createBitmap(intCanvasWidth, intCanvasHeight,
Bitmap.Config.RGB_565);
paint = new Paint();
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
if (thread.getState() == Thread.State.TERMINATED) {
thread = new Thread();
}
mRun = true;
thread.start();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
mRun = false;
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
// we will try it again and again...
}
}
}
Thread thread = new Thread() {
public void doDraw(Canvas c) {
tempCanvas.setBitmap(mDrawing);
paint.setColor(Color.rgb(255, 255,255));
tempCanvas.drawLine(1,1,200,300, paint);
c.drawBitmap(mDrawing, 0, 0, null);
}
#Override
public void run() {
Canvas c;
while (mRun) {
c = null;
try {
c = mSurfaceHolder.lockCanvas(null);
synchronized (mSurfaceHolder) {
doDraw(c);
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
mSurfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
};
}

Here's how my SurfaceView works. I think your problem is doing your Bitmap in surfaceCreated().
#Override
public void surfaceCreated(SurfaceHolder holder) {
thread.start();
}
Thread thread = new Thread(){
...
public void doDraw(Canvas c){
//draw onto the canvas here
}
public void run() {
while (mRun) {
Canvas c = null;
try {
c = mSurfaceHolder.lockCanvas(null);
synchronized (mSurfaceHolder) {
doDraw(c);
}
} finally {
// do this in a finally so that if an exception is thrown
// during the above, we don't leave the Surface in an
// inconsistent state
if (c != null) {
mSurfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
};