android use a View from a XML layout to draw a canvas
Start here (and this needs your input as well for the namespace portion "yourProjectNamespace"):
<?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:orientation="vertical" >
<Button android:id="@+id/bTest"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" />
<sm.view.test.TheSurface android:id="@+id/vMain"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
In your TheSurface
Implement the overideable routines:
public TheSurface(Context C){
super(C);
// Other setup code you want here
}
public TheSurface(Context C, AttributeSet attribs){
super(C, attribs);
// Other setup code you want here
}
public TheSurface(Context C, AttributeSet attribs, int defStyle){
super(C, attribs, defStyle);
// Other setup code you want here
}
protected void onDraw(Canvas canvas){
super.onDraw(canvas);
Paint textPaint = new Paint();
textPaint.setColor(Color.WHITE);
canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), textPaint);
// Other drawing functions here!!!
}
This should get your drawing done!!!
Also in my case, you dont have to implement this as a SurfaceView, you could just implement it as a View, and it does not need to implement runnable!!!
steven minkus
Updated on June 19, 2022Comments
-
steven minkus almost 2 years
So basically i want to use a xml layout, but i also want a canvas where i can have graphics performed. What i did was make a view in my xml layout as you can see below. Then in my application i made the view draw the canvas, but it is not working. I'm not sure if my method for solving this is completely wrong or what. So please just take a look at my code and tell me if you see a quick fix or if you have a better method. Thanks in advance I really appreciate it.
<?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:orientation="vertical" > <Button android:id="@+id/bTest" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Button" /> <View android:id="@+id/vMain" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout>
that is the xml layout
package sm.view.test; import android.app.Activity; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Paint.Align; import android.os.Bundle; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.View.OnTouchListener; import android.widget.Button; public class ViewActivity extends Activity implements OnTouchListener { /** Called when the activity is first created. */ View v; Button b; boolean isRun =true; SurfaceHolder ourHolder; Thread ourThread; Canvas canvas; boolean isTure = true; TheSurface ourSurfaceView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); b= (Button) findViewById(R.id.bTest); v = (View) findViewById(R.id.vMain); canvas = new Canvas(); ourSurfaceView = new TheSurface(this); ourSurfaceView.setOnTouchListener(this); v.draw(canvas); // v.setBackgroundColor(Color.BLUE); } protected void onPause() { // TODO Auto-generated method stub super.onPause(); ourSurfaceView.pause(); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); ourSurfaceView.resume(); } public boolean onTouch(View arg0, MotionEvent arg1) { // TODO Auto-generated method stub return false; } public class TheSurface extends SurfaceView implements Runnable{ public TheSurface(Context context) { super(context); ourHolder= getHolder(); } public void resume(){ isRun= true; ourThread = new Thread(this); ourThread.start(); } public void pause(){ isRun = false; while(true){ try { ourThread.join(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } break; } ourThread= null; } public void run() { // TODO Auto-generated method stub Paint textPaint = new Paint(); textPaint.setColor(Color.WHITE); while(isTure){ if(!ourHolder.getSurface().isValid()) continue; //v.draw(canvas); canvas = ourHolder.lockCanvas(); canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), textPaint); ourHolder.unlockCanvasAndPost(canvas); v.draw(canvas); } } }
}