How to set canvas size?

Question

I have a class called SeatsPanel where I draw places (using drawRect) in the onDraw method. The onDraw method uses Canvas as a parameter, but how do you determine the size of the Canvas? The reason I ask this question is because this class is bloated in another class. I know that the canvas has a default height and width, but I need to reduce its size. How can i do this?

Any help would be appreciated.

-Tolga -

Answer 1

I tried to implement a simple application that draws a black rectangle inside the main action, which is drawn with the click of a button. For example, in MainActivity :

  private Button button1; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); button1=(Button)findViewById(R.id.button); button1.setOnClickListener(new OnClickListener(){ public void onClick(View v) { switch(v.getId()){ case R.id.button: LinearLayout ll=(LinearLayout)findViewById(R.id.linearLayout1); System.out.println(ll.getWidth()+" "+ll.getHeight()); LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ll.getWidth(),ll.getHeight()); YourView yourView = new YourView(getBaseContext()); yourView.setBackgroundColor(Color.WHITE); ll.addView(yourView,params); break; } } }); } 

And in the YourView class:

  private Bitmap savedBitmap; public YourView(Context context) { super(context); } public void onDraw(Canvas canvas) { super.onDraw(canvas); System.out.println(canvas.getWidth()+" "+canvas.getHeight()); Paint textPaint = new Paint(); textPaint.setARGB(255, 0, 0, 0); textPaint.setTextAlign(Paint.Align.RIGHT); textPaint.setTextSize(11); textPaint.setTypeface(Typeface.DEFAULT); canvas.drawColor(Color.WHITE); System.out.println(canvas.getWidth()); System.out.println(canvas.getHeight()); canvas.drawRect(200, 20, 500, 100, textPaint); } 

Main.xml file:

 <?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" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Push the button and draw a Rect" /> <Button android:id="@+id/button" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Button" /> <LinearLayout android:id="@+id/linearLayout1" android:layout_width="match_parent" android:layout_height="match_parent" > </LinearLayout> 

Answer 2

It may not apply in your case, but it works for me

 Bitmap animation = BitmapFactory.decodeResource(mContext.getResources(), resourceId, mBitmapOptions); //Get a bitmap from a image file // Create a bitmap for the part of the screen that needs updating. Bitmap bitmap = Bitmap.createBitmap(animation.getWidth(), animation.getHeight(), BITMAP_CONFIG); bitmap.setDensity(DisplayMetrics.DENSITY_DEFAULT); Canvas canvas = new Canvas(bitmap); 

This sets the canvas size to the bitmap size