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"/>
Related
Can you help me design Android layout as the mockup:
Description:
Orange layout with rounded radius.
Green layout is cut off at bottom and overflow at top
Yellow layout in front of Green and cut off at rounded corner of Orange.
Please help me, I was crazy with this problem.
Thank you so much!
My Code here:
Clipped view
public class ClippedView extends FrameLayout {
public ClippedView(Context context) {
super(context);
}
public ClippedView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ClippedView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void onDraw(Canvas canvas) {
Path clipPath = new Path();
clipPath.addRoundRect(new RectF(canvas.getClipBounds()), 120, 120, Path.Direction.CW);
canvas.clipPath(clipPath);
super.onDraw(canvas);
}
}
It's cut OK but Orange layout cut all side. I want cut children only at bottom
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"
I'm trying to create a custom LinearLayout that can rotate all children in the layout by a set angle. That is, I want to rotate the entire canvas and the children, not the children individually.
I need to support API Level 10, so android:rotate which was introduced in API Level 11 will not help me here.
I've been looking around and think I need to do something along the lines of this code below, but with this code nothing gets rotated.
Any ideas on what I'm missing here?
public class RotationLayout extends LinearLayout {
public RotationLayout(Context context) {
super(context);
init();
}
public RotationLayout(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public RotationLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
setWillNotDraw(false);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.save();
canvas.rotate(350,0,0);
super.onDraw(canvas);
canvas.restore();
}
}`
I tried your code with a few changes.
In the onCreate(Bundle) of an activity class, I initialized the RotationLayout:
RotationLayout rl = new RotationLayout(this);
ImageView iv = new ImageView(this);
iv.setImageDrawable(getResources().getDrawable(R.drawable.some_drawable));
rl.addView(iv);
setContentView(rl);
And the view was indeed rotated 350 degrees(or 10 degrees counter-clockwise) around (0,0). This was what I changed:
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.rotate(350,0,0);
}
From notes on Canvas.save() (Link):
Saves the current matrix and clip onto a private stack. Subsequent
calls to translate,scale,rotate,skew,concat or clipRect,clipPath will
all operate as usual, but when the balancing call to restore() is
made, those calls will be forgotten, and the settings that existed
before the save() will be reinstated.
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'.
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.