I have ScrollView layout (or other layout type it doesn't mater) which has child views. And this parent layout has paddingLeft and paddingRight. I want to have this padding set for each child, but sometimes I have exception where I want that child to reach edges of the display completely (for example TextView with background color). Is there any way how to allow this to happen? I don't wanna set padding for every single child separately.
You told us what you want: "sometimes a Child shouldn't have to respect its Parent padding", so the special behaviour should occurs on Children.
The solution is to EXTEND Child's main View in which it chooses its MARGIN by default and then create a "Child.setNoMargins()" method that removes them from itself when required.
public static class ExtendedTextView extends TextView {
private boolean mHasNoMargins = false;
public ExtendedTextView(Context context) {
super(context);
}
public void setNoMargins() {
mHasNoMargins = true;
if (!isInLayout() && isAttachedToWindow()) requestLayout();
}
#Override
public void setLayoutParams(ViewGroup.LayoutParams params) {
if (!mHasNoMargins && (params instanceof ViewGroup.MarginLayoutParams)) {
((ViewGroup.MarginLayoutParams)params).setMarginStart(20);
((ViewGroup.MarginLayoutParams)params).setMarginEnd(20);
}
super.setLayoutParams(params);
}
}
In this way all created "ExtendedTextView" have default Left/Right margins until you call "setNoMargins()".
Obliviously my code works only if parent ViewGroup supports LayoutParams having Margins (most of them).
Related
I have made class called ProgressButton that extended RelativeLayout.Now in main xml i added this class:
<com.tazik.progressbutton.ProgressButton
android:id="#+id/pb_button"
android:layout_width="200dp"
android:layout_height="wrap_content"/>
As you can see i added android:layout_width="200dp", now in ProgressButton class i want to get this size to create a button with this size:
public class ProgressButton extends RelativeLayout {
private AppCompatButton button;
public ProgressButton(Context context) {
super(context);
initView();
}
private void initView() {
initButton();
}
private void initButton() {
button = new AppCompatButton(getContext());
LayoutParams button_params = new LayoutParams(????, ViewGroup.LayoutParams.WRAP_CONTENT);
button_params.addRule(RelativeLayout.CENTER_IN_PARENT,RelativeLayout.TRUE);
button.setLayoutParams(button_params);
button.setText("click");
addView(button);
}
I want to create button exactly to size of relativeLayout, so how can i get layout_width in my custom view to set button_params width?
now in ProgressButton class i want to get this size to create a button with this size
As #MikeM. suggested in a comment. It could be as easy as giving that child view a width of MATCH_PARENT. See below...
LayoutParams button_params = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
With that in place you don't need to worry about the actual size because MATCH_PARENT will stretch your child view to occupy the whole parent's width...obviosuly respecting margins and paddings.
However, if you do need to know the parent's width, you should query that in onMeasure. I strongly suggest you to stay away from onMeasure whenever possible because it is a bit complex and it might take a lot of your development time.
Either way, in onMeasure you can know what measurements the parent view wants to give to its child views, this is based on the space available to render inside the parent and the layout params specified...
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
int childWidth = 0;
if(widthSpecMode == MeasureSpec.AT_MOST){
//The parent doesn't want the child to exceed "childWidth", it doesn't care if it smaller than that, just not bigger/wider
childWidth = MeasureSpec.getSize(widthMeasureSpec);
}
else if(widthSpecMode == MeasureSpec.EXACTLY){
//The parent wants the child to be exactly "childWidth"
childWidth = MeasureSpec.getSize(widthMeasureSpec);
}
else {
//The parent doesn't know yet what its children's width will be, probably
//because it's still taking measurements
}
//IMPORTANT!!! set your desired measurements (width and height) or call the base class's onMeasure method. Do one or the other, NOT BOTH
setMeasuredDimension(dimens, dimens);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
Add a few Log.d calls inside onMeasure for a better understanding of what's happening. Be aware that this method will be called multiple times.
Again, this is an unnecessary overkill for your case scenario. Setting MATCH_PARENT to the button should produce the results you want
I'm trying to make a set of views (that include several textviews and buttons - all in different parent layouts, but in the same activity) invisible if a particular condition is evaluated to false.
The conventional way to do that would be:
findViewById(R.id.myview).setVisibility(View.INVISIBLE);
My question is, will I have to do this for all the views one by one that I want to be invisible, And then toggle them back when I want them visible?
Or, is there a way to avoid the code-repetition?
If the Views are in different parents , you can't do it directly, but you can implement a method to change the visibility of a bunch of Views if you want to keep your code clean:
List<View> relatedViews = new ArrayList<>();
// ...
relatedViews.add(view1);
relatedViews.add(view2);
relatedViews.add(view3);
// ...
changeVisibility(relatedViews, View.INVISIBLE);
// ...
private void changeVisibility(List<View> views, int visibility) {
for (View view : views) {
view.setVisibility(visibility);
}
}
As a side note, you may want to change the visibility to View.GONE instead of View.INVISIBLE so it doesn't take any space in the layout.
you can use something like this. It's not the most elegant solution but works.
The idea is give to each view that you want to hide a same content description, because in the same layout you can not use same id for multiple view. With the same content description you can find all views in your layout and hide them.
That's an example considering the first layout as Linear. You can change obviously ;)
public class TestActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
LinearLayout rootLayout = (LinearLayout)findViewById(R.id.rootLayout);
int childcount = rootLayout.getChildCount();
for (int i=0; i < childcount; i++){
View v = rootLayout.getChildAt(i);
if(v.getContentDescription() != null && v.getContentDescription().equals("invisibleView")){
v.setVisibility(View.INVISIBLE);
//I suggest you to use GONE instead of INVISIBLE to remove the space of the view
}
}
}
}
in your xml give to the object that you want to hide this property
android:contentDescription="invisibleView"
Use varargs method for show or hide multiple views.
for example if you have views like view1, view2.....etc
then just call setVisibility(View.VISIBLE,view1,view2)
public static void setVisibility(int visibility, View... views){
for (View view : views){
view.setVisibility(visibility);
}
}
I want to create the following concept:
First expand the view to its parent's width (it's not the same).
Then expand the view to its parent's height.
I know I can create the sequence with AnimatorSet(). What I cannot find is what property/-ies to animate to create the result.
My thoughts for the width animation:
I would probably need to animate either two points which define left and right or alternatively animate the translation and the width.
I'm a bit confused, which properties would do the trick?
You'll need to define custom properties to do this (I know, silly). Height example:
public static final Property<View, Integer> PROPERTY_HEIGHT =
new Property<View, Integer>(Integer.class, "viewLayoutHeight") {
#Override
public void set(View object, Integer value) {
object.getLayoutParams().height = value.intValue();
object.requestLayout();
}
#Override
public Integer get(View object) {
return object.getLayoutParams().height;
}
};
Then use as a normal property:
ObjectAnimator.ofInt(view, PROPERTY_HEIGHT, minHeight, maxHeight);
You'll need to get the parent dimensions at runtime (perhaps using a ViewTreeObserver.OnGlobalLayoutListener).
I think that there is no need to complicate things, you can use width property first then followed by height in AnimatorSet, Your view gravity property will define in which direction view will expand ...
I have a form within a ScrollView. When I tap into an EditText the soft keyboard appears and the ScrollView scrolls the now focused EditText so that it just comes into view.
However, I have hint information just below the EditText that I also would like to show, so the scrolling should go just a bit further up, like this:
The EditText is embedded in a form element and actually I'd like to scroll to the bottom of that. I've checked the source code of ScrollView and it will just scroll to the bottom of the currently focused view. Maybe there's a way to tell the ScrollView that the form element is the currently focused element?
Of course I could write my own ScrollView sub class and override the scroll behavior, but I wonder if there's a more elegant way of doing this.
Any other suggestions (with adjust scrolling with a fixed offset or so) are also appreciated.
I have not really found any way to configure the scrolling behavior of the ScrollView from the outside. So I ended up to define my own sub class of ScrollView:`
/**
* {#link ScrollView} extension that allows to configure scroll offset.
*/
public class ConfigurableScrollView extends ScrollView {
private int scrollOffset = 0;
public ConfigurableScrollView (final Context context, final AttributeSet attrs) {
super(context, attrs);
}
public void setScrollOffset (final int scrollOffset) {
this.scrollOffset = scrollOffset;
}
#Override
protected int computeScrollDeltaToGetChildRectOnScreen (final Rect rect) {
// adjust by scroll offset
int scrollDelta = super.computeScrollDeltaToGetChildRectOnScreen(rect);
int newScrollDelta = (int) Math.signum(scrollDelta) * (scrollDelta + this.scrollOffset);
return newScrollDelta;
}
}
computeScrollDelta(...) is the only protected method that can be targeted for overriding, apart from onSizeChanged(...).
The signum function in the example above ensures that scrolling is only increased, if the ScrollView really thinks that scrolling is necessary (e.g. when keyboard pops up).
I can now set the extra scroll offset once from the outside, as calculated from the height of the hint.
It's not hard to use the extended ConfigurableScrollView instead of the standard ScrollView, I only had to replace the ScrollView XML tag with the FQN of the new class.
Considering that you are using ScrollView you have the possibility to use the method ScrollTo as follow:
scrollView.post(new Runnable() {
#Override
public void run() {
sv.scrollTo(x-value, y-value);
}
});
where the first argument is the scroll value for X, while the second argument is the scroll value for Y. So you just have to set your scrollView offset when the keyboard is displayed.
Hope it helps;)
I have 2 webviews on one layout.
I want that on touch, the touched view will get bigger (wider) on the expense of the other view, how can I do it?
Thanks!
Subclass WebView:
public class MyWebView extends WebView{
private MyActivity mActivity;
//Call this on each webview in activity's onCreate after
//instantiating the web views. i.e. after setContentView()
//and assigning it to a variable with findViewById() or
//after programmatically creating the web view.
public setActivity(MyActivity activity){
mActivity = activity;
}
#Override
public boolean onTouchEvent(MotionEvent event){
if (event.getAction()==ACTION_POINTER_DOWN && mActivity!=null){
mActivity.onWebviewTouched(self);
}
super.onTouchEvent(event);
}
}
And in your Activity:
public void onWebviewTouched(MyWebView webView) {
if (webView == mWebviewLeft){
//grow left webview if it isn't already grown, and shrink right webview.
} else if (webView == mWebviewRight) {
//grow right webview if it isn't already grown, and shrink left webview.
}
}
Use the Animation class and its subclasses to modify width of the views smoothly. If using a LinearLayout, you could set one view's layout weight to a constant value, and simply animate the layout weight of the other view to get bigger or smaller than that constant value.
If you just want an instant change, just set the view widths directly with LayoutParams.