android pinch zoom scale view scrollbar moves - android

i have a view in linear layout. the app is music notation which is a series of musical bars which line wrap so they always less than width of screen (no horizontal scrolling). there is a vertical scrollbar when the music score gets too big for the view. so far so good. i can scroll up and down fine.
now i'm implementing pinch zoom, i set up an onScale in a ScaleGestureDetector, save the scale factor, invalidate and in onDraw i use the scale factor like this canvas.scale(mScaleFactor, mScaleFactor);
it scales the view ok except its not doing exactly what i want. i want the drawing area of the canvas to scale as it does but the scrollbar to stay in place, but zooming sends it off to the side, out of view.
any idea how to scale the view but not the scrollbar?
BTW, i can recalculate where to line wrap my music bars by applying the scalefactor to the width, its really just a problem with the scrollbar display.
can anyone help? thanks

I figured out the way. I needed to decouple the drawing of the scrollbar from the drawing of the main music notation view. that way I can zoom the main notation view without affecting the scroll bar.
so I use linear layout to create 2 views -
layout.setLayoutParams(new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT,
100));
layout.setOrientation(LinearLayout.HORIZONTAL);
Globals.mMainView = new MainView(context);
Globals.mMainView.setLayoutParams(new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WRAP_CONTENT, 60));
layout.addView(Globals.mMainView);
Globals.mScrollbarView = new ScrollbarView(context);
Globals.mScrollbarView.setLayoutParams(new LinearLayout.LayoutParams(20, LinearLayout.LayoutParams.WRAP_CONTENT, 0));
layout.addView(Globals.mScrollbarView);
then I remove display of scrollbars from MainView and put them in ScrollbarView.
then I use onScroll events in ScrollbarView to control scrolling in MainView. I have to remember to return the actual display length of MainView from ScrollbarView.computeVerticalScrollRange so the scroll bar size shows up ok.
since I have reference to both views saved as globals, its easy for them to talk to each other as necessary.

Related

Android Game development - Imageview automatically shrinks at screen edge

I have a bunch of dynamically created ImageViews representing different objects in a game, which is working fine. However if any Image reaches the edge of the screen, it shrinks. Looks like android is attempting to create a smooth transition, but this is not wanted.
I found another thread with the same issue here: Animation Drawable gets automatically shrinks at the corners ?, however his solution does not work for me, it only enhances the issue as it starts shrinking once the margin hits the screen edge.
This is my code:
final LayoutParams _updated_params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
_updated_params.setMargins((int)m_x, (int)m_y, 0, 0);
m_image.setLayoutParams(_updated_params);</code>
Where m_x/m_y is the absolute position of the image and m_image is an ImageView instance.
Does anyone know how I can turn off this automatic resizing?
Add setScaleType
m_image.setScaleType(ScaleType.MATRIX);
Use setScaleType
m_image.setScaleType(ScaleType.FIT_XY);

Can android padding be made to be not clickable?

EDIT: Answer found through Emil's comments. Code ended up like this:
FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.WRAP_CONTENT,
FrameLayout.LayoutParams.WRAP_CONTENT);
params.setMargins(left, top, right, bottom);
view.setLayoutParams(params);
Thanks all :D
I'm currently writing an Android application and I have a dynamically created tree which displays ImageView elements within it. However, to arrange these images I've used padding left to line them up correctly, dynamically changing how the padding is calculated so that everything turns out evenly. However when I do this, the padding covers up some of the images to the left, and even though you can see the images behind this padding, when you click on that image, it will evaluate the image who's padding is being used (the furthest left element). I'm basically wondering if there is a way to programatically set something that does what padding does to images but isn't clickable? Margins would make sense, but you cannot set margins on ImageViews.
The tree set up is like this:
-----A-----
--B--C--D--
-E-F----G--
Imagine every letter is an ImageView, dynamically placed with padding. But if I click on B or C, D's code will be evaluated because it's left padding covers B and C. The same goes for E or F, click those, and G will be evaluated. I cannot figure out a different way to place these ImageViews. Any help is greatly appreciated.
Consider replacing your padding with layout_margin property. that way the area that separates the padded view is not considered as part of the view but ratter as part of the layout it sits in.
So use
android:layout_margin="10dp"
or:
android:layout_marginLeft="10dp"
for your needs.

move the screen content to the left outside the screen android

is there a way to move the whole screen content outside the screen bounds, with titlebar and all, on the left for example, i tried
content = ((LinearLayout) act.findViewById(android.R.id.content)
.getParent());
to get the screen content and add a margin to it
FrameLayout.LayoutParams pr = (android.widget.FrameLayout.LayoutParams) content
.getLayoutParams();
pr.rightMargin = xOffset;
content.setLayoutParams(pr);
but it doesnt work, the margin appears but the content is not moved just resized to fit the screen, anyone know how to do this the simple way?
you can set the margin in negative(-) values.
for example if your want the layout to move upper use this:
android:marginTop = "-50dip or more u can put"
Are you trying to flip between views? As in, moving that layout off the screen to show another one? If so you should look at using a widget called ViewFlipper which will do exactly as you need. It can also be animated etc.
http://developer.android.com/reference/android/widget/ViewFlipper.html

Positioning items relative to the ActionBar in Android

I used to have an Activity that would use no ActionBar. The layout is a RelativeLayout with width and height simply matching the parent. It allowed users to drag around buttons using parts of this code in the onTouch event:
MarginLayoutParams marginParams = new MarginLayoutParams(v.getLayoutParams());
int left = (int) event.getRawX() - (v.getWidth() / 2);
int top = (int) event.getRawY() - (v.getHeight());
marginParams.setMargins(left, top, 0, 0);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(marginParams);
v.setLayoutParams(layoutParams);
All dandy—the button moves just below the finger and is placed correctly at the position on screen. Now, however, I enabled the ActionBar, and suddenly when clicked, the button moves ~30 pixels below the finger. To illustrate this behavior, here's what I used to have (on the left) and what happens right now (on the right):
I assume this is because the ActionBar now displaces everything by its own height. Of course, I do not want this to happen, or at least correct this, so:
How can I shift the placement in setMargins() according to the actual size of the ActionBar without using a hardcoded value?
How can I prevent the ActionBar from shifting everything in the first place? Put differently, how can I ensure my button is placed relative to the ActionBar's bottom line and directly where the finger points?
This is what I want:
(I used an approach is my code and it works. I am going to tell you the same here)
I think setMargin() is not such a clever thing to use here. Instead you can use setX() and setY() methods.
Whenever one switches over from a full screen activity to the one with Action Bar, one runs into such problem.
You will need to adjust for the Action Bar height. Instead of using getLayoutParams(), use getLocationInWindow() or getLocationOnScreen(). Since getRawX() and getRawY() work with screen positions of the view, these APIs should be used.

Android - How to draw a letter at a specific point?

I want to fill the screen with a 100 different letters in random positions. On the iPhone I just created a bunch of UILabels set their x and y positions and then used animations to move them about.
On Android it doesn't look like I can add a TextView to my view and specify its X and Y. Is there a way to do this?
View gameView = findViewById(R.id.gameboard);
tv = new TextView(gameView.getContext());
tv.setText("A");
tv.setWidth(w); tv.setHeight(h);
// How to set the X and Y?
EDIT: The solution was to use AbsoluteLayout:
AbsoluteLayout al = (AbsoluteLayout)findViewById(R.id.gb_layout);
tv = new TextView(this);
AbsoluteLayout.LayoutParams params = new AbsoluteLayout.LayoutParams(
AbsoluteLayout.LayoutParams.WRAP_CONTENT,
AbsoluteLayout.LayoutParams.WRAP_CONTENT,10,10);
params.x = 50;
params.y = 50;
al.addView(tv, params);
and to move it base on MotionEvent me:
AbsoluteLayout.LayoutParams p = new AbsoluteLayout.LayoutParams(
AbsoluteLayout.LayoutParams.WRAP_CONTENT,
AbsoluteLayout.LayoutParams.WRAP_CONTENT,(int)me.getX(), (int)me.getY());
mTV.setLayoutParams (p);
I think you are making a game and for this you should look into SurfaceView here is an good example then
1...if you look into code there is onDraw method where you will get the width of screen and height
2...Now taking this width and height as seed for random generator get x and y position.
3...Iterate through point 2 100 times and you will get the desired result
You can use a FrameLayout for this. Set each TextView's background to transparent and add it to the FrameLayout. Make each TextView, and the FrameLayout, fill their parent. The FrameLayout places all its child views at (0,0). To move letters around, just change the top and left padding of the corresponding TextView.
In android positioning child views is the responsibility of the layout class.
You need to create a custom.layout and overide the onLayout method. In this method you can iterate through all the child views calling View.layout(left,top,right,bottom) on each child.
i found this example code whilst trawling the net :
https://gist.github.com/882650
You should also check out view.setTranslationX (and Y) which might be exactly what you need
I'm not entirely sure how you'd go about doing this in code, but you need to use an absolute layout as your root element. (edit: Do not use absolute layout, as it was pointed out that it is deprecated. The closest alternative seems to be RelativeLayout.)
The properties in the XML format for the absolute layout coordinates are layout_x and layout_y.
edit: A little research is saying you need to be using setLayoutParams, but my Eclipse IDE is not working properly, so unfortunately I can't test exactly what you're looking for.

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