Develop Reference

Keep text inside diamond shaped background

I'm drawing a blank here!
I have a textview with a diamond shaped background. The text needs to be contained within the diamond.
Like this.
How do I do this? Is there a way to define the bounds of the text inside a textview?

Edit
Put the below code in a java class like DiamondTextView:
public class DiamondTextView extends TextView{
public DiamondTextView(Context ctx, AttributeSet attrs) {
super(ctx, attrs);
}
Paint mBorderPaint = new Paint();
#Override
protected void onDraw(Canvas canvas) {
mPath.moveTo(mWidth/2 , 0);
mPath.lineTo(mWidth , mHeight/2);
mPath.lineTo(mWidth /2 , mHeight);
mPath.lineTo(0 , mHeight/2);
mPath.lineTo( mWidth/2 ,0);
//setup the paint for fill
mBorderPaint.setAlpha(255);
mBorderPaint.setColor(mBorderColor);
mBorderPaint.setStyle(Paint.Style.FILL);
borderPaint.setStrokeWidth(mBorderWidth);
//draw it
canvas.drawPath(mPath ,mBorderPaint);
//setup the paint for stroke
mBorderPaint.setAlpha(51);
mBorderPaint.setStyle(Paint.Style.STROKE);
//draw it again
canvas.drawPath(mPath ,mBorderPaint);
super.onDraw(canvas);
}
}
and call it as where you want to use this textView :
<com.erginus.ABC.Commons.DiamondTextView...../>
For more infomation look here:http://developer.android.com/reference/android/graphics/drawable/shapes/PathShape.html
You can use the following library too: https://github.com/siyamed/android-shape-imageview

Draw a line in Android without setting it as content

Just a newbie here.
Is it possible to draw a line over a layout?
I have an XML file(activity_main) and it contains a layout which is ImageLayout that I took from github. The layout contains an image and several buttons.
What I want to do is to draw a line between two points on the layout. In order to draw a line, people usually create a Draw class and extends View. On the MainActivity, they would setContent the Draw class. I have already setContent my XML file. How would I draw a line from this point?
EDIT:
I heard about the class Path, I think it is better than using onDraw because I would be connecting(drawing lines between) several points in my layout.
Enlighten me about it if you could

Subclass the container ViewGroup and override its dispatchDraw() method. I am providing example of subclassed LinearLayout, however, this would work with any other ViewGroup.
public class MyLinearLayout extends LinearLayout {
private Paint paint;
public MyLinearLayout(Context context) {
super(context);
initPaint();
}
public MyLinearLayout(Context context, AttributeSet attrs) {
super(context, attrs);
initPaint();
}
public MyLinearLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initPaint();
}
private void initPaint() {
paint = new Paint();
paint.setColor(Color.RED);
paint.setStrokeWidth(10);
}
#Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
canvas.drawLine(0, 0, canvas.getWidth(), canvas.getHeight(), paint);
}
}

Use this in your layout to do an horizontal line:
android:layout_width="fill_parent"
android:layout_height="2dp"
android:background="#c0c0c0"/>

How to set scaleType and adjustViewBounds in Custom ImageView

I've created a custom ImageView class, as I wanted to override the onDraw method for my Canvas; however, the XML attributes scaleType="centerInside" and adjustViewBounds="true" are not being inherited by my custom ImageView class. If I switch to the default ImageView, everything works fine - but how can I have it work in my custom Image View?
In the class below, I'm simply retrieving a bitmap from my application class and drawing it to the canvas; however, when using my CustomImageView - the image is massive and not scaled properly. Any idea how to fix this? Thanks!
Custom ImageView XML:
<com.project.app.controls.CustomImageView
android:id="#+id/myImage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="centerInside"/>
Custom ImageView Class:
public class CustomImageView extends ImageView {
ProjectApp wApp;
Paint paint;
public CustomImageView(Context context, AttributeSet attrs) {
super(context, attrs);
wApp = ProjectApp.createInstance();
paint = new Paint();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
canvas.drawBitmap(wApp.photoTaken, 0, 0, null);
}
}

public CustomImageView(Context context, AttributeSet attrs) {
super(context, attrs);
wApp = ProjectApp.createInstance();
paint = new Paint();
setAdjustViewBounds(true);
setScaleType(ImageView.ScaleType.CENTER_INSIDE);
}

I think you want to use fitXY instead so the image will be bound by the constraints of the CustomImageView's layout params (and its parent in this case).
android:scaleType="fitXY"

Paint over the specific area in Android

I want to draw over the specific Line, Rectangle or Bitmap using Canvas. If i draw over the Bitmap, it will take the square shape empty background also.
So i want to draw over that particular Bitmap area only.

create a bitmap with "bmp1" name from your desire image
create a custom view
create a class and extend View like this
class MyCustomView extends View{
private Rect m_ImageRect;
private Rect m_TextRect ;
//you need these constructor
//you can init paint object or anything on them
public MyCustomView (Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
m_Context = context;
}
public MyCustomView (Context context, AttributeSet attrs)
{
super(context, attrs);
m_Context = context;
}
public MyCustomView (Context context)
{
super(context);
m_Context = context;
}
//then override on draw method
#Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
//here frist create two rectangle
//one for your image and two for text you want draw on it
m_ImageRect = canvas.getClipBounds();
m_TextRect = canvas.getClipBounds();
//it gives you an area that can draw on it,
//the width and height of your rect depend on your screen size device
canvas.drawBitmap(your bitmap(bmp1), null, m_ImageRect , paint);
canvas.save();
canvas.clipRect(m_TextRect);
canvas.drawText("your text", the x position you want to start draw,
the y position you want to start draw, m_paintText);
canvas.restore();
}
}
at the end put the custom view on your layout,and set field on it to send value to view for draw every thing you want
i hope it's help you,if this is not what you want!
post your code so maybe i can help you more

Seems like you need clipping. See exampls: http://www.example8.com/category/view/id/15543 , Understanding Android Canvas Clipping , http://jtomlinson.blogspot.com/2008/10/clipping.html
With clipping you can specify, which regions should be 'editable'.

Android canvas issue

I am new to android. Now I generated two ImageView in my Android XML file. I want to use canvas to draw two circles in each view. But the problem is, how can I deal with the coordinates? How can I know the coordinates? And how can I center them? Thanks!

ImageViews are for displaying image files, normally. If you want to draw your view yourself, you create your own View and override the onDraw method. Here is a class that draws a big red circle inside itself:
public class CircleView extends View {
public CircleView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public CircleView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CircleView(Context context) {
super(context);
}
#Override
protected void onDraw(Canvas canvas) {
Paint red = new Paint();
red.setColor(0xffff0000);
int height = getHeight();
int width = getWidth();
int radius = width < height ? width/2 : height/2;
canvas.drawCircle(width/2, height/2, radius, red);
}
}

You cannnot draw cirlces in an ImageView. You can only draw a circle in a bitmap and apply that bitmap to an ImageView.
Or you can create custom views and draw directly on their canvas.
In both cases you need to find the size of these views after they are created. Then you will know the coordinates as the 0,0 starts in the top left corner.