Using `Rect` you define its edges using integers and using `RectF` they are defined as floats.

Looking at them more carefully I have spotted a few differences actually. I will only list what one implementation has more compared to the other one.

**Rect**

 - [equals(Object obj)][1] (for some reason it has its own implementation of equals)
 - [exactCenterX()][2]
 - [exactCenterY()][3]
 - [flattenToString()][4]
 - [toShortString()][5]
 - [unflattenFromString(String str)][6]

**RectF**

 - [round(Rect dst)][7]
 - [roundOut(Rect dst)][8]
 - [set(Rect src)][9]


So apparently there are some differences.

  [1]: http://developer.android.com/reference/android/graphics/Rect.html#equals(java.lang.Object)
  [2]: http://developer.android.com/reference/android/graphics/Rect.html#exactCenterX()
  [3]: http://developer.android.com/reference/android/graphics/Rect.html#exactCenterY()
  [4]: http://developer.android.com/reference/android/graphics/Rect.html#flattenToString()
  [5]: http://developer.android.com/reference/android/graphics/Rect.html#toShortString()
  [6]: http://developer.android.com/reference/android/graphics/Rect.html#unflattenFromString(java.lang.String)
  [7]: http://developer.android.com/reference/android/graphics/RectF.html#round(android.graphics.Rect)
  [8]: http://developer.android.com/reference/android/graphics/RectF.html#roundOut(android.graphics.Rect)
  [9]: http://developer.android.com/reference/android/graphics/RectF.html#set(android.graphics.Rect)

How do [`Object.hashCode()`][1] and [`System.identityHashCode()`][2] work at the back end? Does `identityHashCode()` return the reference of the object? Does `hashCode()` depend on the content or address of the object? 

What is the difference between `hashCode()` and `identityHashCode()`? 


  [1]: http://download.oracle.com/javase/6/docs/api/java/lang/Object.html#hashCode()
  [2]: http://download.oracle.com/javase/6/docs/api/java/lang/System.html#identityHashCode(java.lang.Object)

How do hashCode() and identityHashCode() work at the back end?

Can private classes exist in C#, other than in Inner classes? 

Concept of Private class in C#

What is the difference between Rect and RectF in the Android SDK?

Rect and RectF in Android SDK

<p>What is the difference between Rect and RectF in the Android SDK?</p>


Is it possible to set the Margins of a LinearLayout, programmatically but not with pixels, but dp?

Margins of a LinearLayout, programmatically with dp

I&#39;m doing a small research of mobile platforms and I would like to know which design patterns are used in Android?

e.g. in iOS Model-view-controller is very widely used together with delegation and other patterns. 

What patterns and where in particular does Android use?

**EDIT**

I&#39;m not asking for design patterns used deep in kernel, dalvik and so on, but about patterns which an application developer will meet while developing an application.

Which Architecture patterns are used on Android?

How to set property &quot;`android:drawableTop`&quot; of a button at runtime

How to set property &quot;android:drawableTop&quot; of a button at runtime

I have a table layout that I want to populate with the result from a database query. I use a select all and the query returns four rows of data. 

I use this code to populate the TextViews inside the table rows.

```java
Cursor c = null;
c = dh.getAlternative2();
startManagingCursor(c);
// the desired columns to be bound
String[] columns = new String[] {DataHelper.KEY_ALT};
// the XML defined views which the data will be bound to
int[] to = new int[] { R.id.name_entry};

SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, 
		 R.layout.list_example_entry, c, columns, to);
this.setListAdapter(mAdapter);
```

I want to be able to separate the four different values of KEY_ALT, and choose where they go. I want them to populate four different TextViews instead of one in my example above.

How can I iterate through the resulting cursor?

Iterate through rows from Sqlite-query

I&#39;m calling `finish()` but my activity keeps on going.

I have an activity which is invoked by a menu from the main activity screen.  In my activity&#39;s `onCreate()` method I have the following code fragment:

        // Make sure there are some events in the list.
        if (theEventArrayList.isEmpty()){
            Toast.makeText(this, &quot;Event List is empty&quot;, Toast.LENGTH_LONG).show();
            finish();
        }
        SummarizeCurrentEvent();
        graphEvents();

If the list is empty it puts up the Toast, and I can set breakpoint on the call to `finish()`. If I step from that in the debugger it goes to straight to `SummarizeCurrentEvent()`.   I thought `finish()` would exit the activity. Is this not the case? Where can I find out more information about this method?

Calling finish() on an Android activity doesn&#39;t actually finish

How can I get an image to the canvas in order to draw on that image?

Drawable image on a canvas

I&#39;d like to create an empty bitmap and set a canvas to that bitmap and then draw any shape on the bitmap.



Creating an empty bitmap and drawing though canvas in Android

In order to make a simple game, I used a template that draws a canvas with bitmaps like this:

    private void doDraw(Canvas canvas) {
        for (int i=0;i&lt;8;i++)
            for (int j=0;j&lt;9;j++)
                for (int k=0;k&lt;7;k++)   {
        canvas.drawBitmap(mBits[allBits[i][j][k]], i*50 -k*7, j*50 -k*7, null); } }
(The canvas is defined in &quot;run()&quot; / the SurfaceView lives in a GameThread.)

My first question is how do I clear (or redraw) the _whole_ canvas for a new layout?&lt;br&gt;
Second, how can I update just a part of the screen? &lt;br&gt;&lt;br&gt;

    // This is the routine that calls &quot;doDraw&quot;:
    public void run() {
        while (mRun) {
            Canvas c = null;
            try {
                c = mSurfaceHolder.lockCanvas(null);
                synchronized (mSurfaceHolder) {
                    if (mMode == STATE_RUNNING) 
                        updateGame();
                    doDraw(c);          }
            } finally {
                if (c != null) {
                    mSurfaceHolder.unlockCanvasAndPost(c);  }   }   }       }

Android, canvas: How do I clear (delete contents of) a canvas (= bitmaps), living in a surfaceView?

I would like to have a better understanding of how the components of Android&#39;s (2D) Canvas drawing pipeline fit together.

For example, how do [XferMode](http://developer.android.com/reference/android/graphics/Xfermode.html), [Shader](http://developer.android.com/reference/android/graphics/Shader.html), [MaskFilter](http://developer.android.com/reference/android/graphics/MaskFilter.html) and [ColorFilter](http://developer.android.com/reference/android/graphics/ColorFilter.html) interact? The reference docs for these classes are pretty sparse and the docs for [Canvas](http://developer.android.com/reference/android/graphics/Canvas.html) and [Paint](http://developer.android.com/reference/android/graphics/Paint.html) don&#39;t really add any useful explanation.

It&#39;s also not entirely clear to me how drawing operations that have intrinsic colors (eg: `drawBitmap`, versus the &quot;vector&quot; primitives like `drawRect`) fit into all of this -- do they always ignore the `Paint`&#39;s color and use use their intrinsic color instead?

I was also surprised by the fact that one can do something like this:

    Paint eraser = new Paint();
    eraser.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
    canvas.drawOval(rectF, eraser);

This erases an oval. Before I noticed this my mental-model was that drawing to a canvas (conceptually) draws to a separate &quot;layer&quot; and then that layer is composed with the Canvas&#39;s Bitmap using the Paint&#39;s transfer mode. If it were as simple as that then the above code would erase the entire Bitmap (within the clipping region) as CLEAR *always* sets the color (and alpha) to 0 regardless of the source&#39;s alpha. So this implies that there&#39;s an additional sort of masking going on to constrain the erasing to an oval.

I did find the [API demos](http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/index.html) but each demo works &quot;in a vacuum&quot; and doesn&#39;t show how the thing it focusses on (eg: XferModes) interacts with other stuff (eg: ColorFilters).

With enough time and effort I could empirically figure out how these pieces relate or go decipher the source, but I&#39;m hoping that someone else has already worked this out, or better yet that there&#39;s some actual documentation of the pipeline/drawing-model that I missed.

This question was inspired by seeing the code in [this answer to another SO question](https://stackoverflow.com/questions/4560265/android-edit-bitmap-channels/4632210#4632210).

Update
-

While looking around for some documentation it occurred to me that since much the stuff I&#39;m interested in here seems to be a pretty thin veneer on top of [skia](http://code.google.com/p/skia/), maybe there&#39;s some skia documentation that would be helpful. The best thing I could find is [the documentation for `SkPaint`](http://code.google.com/p/skia/wiki/SkPaint) which says:

&gt; There are 6 types of effects that can
&gt; be assigned to a paint:
&gt; 
&gt; - SkPathEffect - modifications to the geometry (path) before it generates an
&gt; alpha mask (e.g. dashing)
&gt; - SkRasterizer - composing custom mask layers (e.g. shadows)
&gt; - SkMaskFilter - modifications to the alpha mask before it is colorized and
&gt; drawn (e.g. blur, emboss)
&gt; - SkShader - e.g. gradients (linear, radial, sweep), bitmap patterns
&gt; (clamp, repeat, mirror)
&gt; - SkColorFilter - modify the source color(s) before applying the xfermode
&gt; (e.g. color matrix)
&gt; - SkXfermode - e.g. porter-duff transfermodes, blend modes

It isn&#39;t stated explicitly, but I&#39;m guessing that the order of the effects here is the order they appear in the pipeline.


How do the pieces of Android&#39;s (2D) Canvas drawing pipeline fit together?

I found a function for rectangles with all 4 corners being round, but I want to have just the top 2 corners round. What can I do?

    canvas.drawRoundRect(new RectF(0, 100, 100, 300), 6, 6, paint);

How to use android canvas to draw a Rectangle with only topleft and topright corners round?

I want to display some text _inside_ SVG `rect`. Is it possible?

I tried 

    &lt;svg xmlns=&quot;http://www.w3.org/2000/svg&quot;&gt;
      &lt;g&gt;
        &lt;rect x=&quot;0&quot; y=&quot;0&quot; width=&quot;100&quot; height=&quot;100&quot; fill=&quot;red&quot;&gt;
          &lt;text x=&quot;0&quot; y=&quot;10&quot; font-family=&quot;Verdana&quot; font-size=&quot;55&quot; fill=&quot;blue&quot;&gt; Hello &lt;/text&gt;
        &lt;/rect&gt;
      &lt;/g&gt;
    &lt;/svg&gt;

But it does not work.

SVG: text inside rect

Currently building a browser-based SVG application. Within this app, various shapes can be styled and positioned by the user, including rectangles.

When I apply a `stroke-width` to an SVG `rect` element of say `1px`, the stroke is applied to the `rect`’s offset and inset in different ways by different browsers. This is proving to be troublesome, *especially* when I try to calculate the outer width and visual position of a rectangle and position it next to other elements. 

For example:

- Firefox adds 1px inset (bottom and left), and 1px offset (top and right)
- Chrome adds 1px inset (top and left), and 1px offset (bottom and right)

My only solution so far would be to draw the actual borders myself (probably with the `path` tool) and position the borders behind the stroked element. But this solution is an unpleasant workaround, and I’d prefer not to go down this road if possible.

So my question is, can you control how an SVG’s `stroke-width` is drawn on elements?

Content Type	Original Author	Original Content on Stackoverflow
Question	Iulius Curt	View Question on Stackoverflow
Solution 1 - Android	Octavian A. Damiean	View Answer on Stackoverflow
Solution 2 - Android	JayJay	View Answer on Stackoverflow

Rect and RectF in Android SDK

Android Problem Overview

Android Solutions

Solution 1 - Android

Solution 2 - Android

Concept of Private class in C#

How do hashCode() and identityHashCode() work at the back end?

Attributions