Develop Reference

How to add a custom view to an activity?

I know this has been asked many times on SO, but somehow I don't get to the solution reading the existing answers.
The most simple thing, I want to add a custom view in an activity.
The custom view MyView has a background color, as well as its subView.
But the activity is just plain white and does not seem to display the custom view.
Why is that?
MainAcivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
MyView myView = findViewById(R.id.myView);
}
}
main_activity.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.myapp.MyView
android:id="#+id/myView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true" />
</RelativeLayout>
MyView.java
public class MyView extends LinearLayout {
public MyView(Context context) {
super(context);
init(context);
}
public MyView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
init(context);
}
public MyView(Context context, #Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context) {
inflate(context, R.layout.my_view, this);
subView = findViewById(R.id.subView);
//...
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
}
}
my_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#ff00ff"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<ImageView
android:id="#+id/subView"
android:layout_width="30dp"
android:layout_height="30dp"
android:background="#ff00ff"
tools:ignore="ContentDescription" />
</LinearLayout>

If you don't skip onLayout implementation in you snippet then you remove layout logic of your custom view, just don't override it:
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
}

set center_horizontal for child of FrameLayout

In this below code i want to set center_horizontal as attachmentSlidingLayer view id but layout_gravity and gravity for parent and child view doesn't work correctly and by default gravity is left side
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:slidingLayer="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<io.codetail.widget.RevealFrameLayout <!-- extends from FrameLayout -->
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center_horizontal">
<com.test.libraries.SlidingLayer <!-- extends from BoundedFrameLayout-->
android:id="#+id/attachmentSlidingLayer"
android:layout_width="match_parent"
android:layout_height="210dp"
android:layout_gravity="center_horizontal"
android:elevation="5dp"
app:bounded_width="450dp"
android:foregroundGravity="center_horizontal">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center_horizontal"
android:gravity="center_horizontal"
android:background="#drawable/sheet_shadow"
android:orientation="vertical"
app:bounded_width="450dp">
</LinearLayout>
</<com.test.libraries.SlidingLayer.SlidingLayer >
</io.codetail.widget.RevealFrameLayout>
</android.support.design.widget.CoordinatorLayout>
BoundedFrameLayout class:
public class BoundedFrameLayout extends FrameLayout {
private final int mBoundedWidth;
private final int mBoundedHeight;
public BoundedFrameLayout(Context context) {
super(context);
mBoundedWidth = 0;
mBoundedHeight = 0;
}
public BoundedFrameLayout(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.BoundedView);
mBoundedWidth = a.getDimensionPixelSize(R.styleable.BoundedView_bounded_width, 0);
mBoundedHeight = a.getDimensionPixelSize(R.styleable.BoundedView_bounded_height, 0);
a.recycle();
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// Adjust width as necessary
int measuredWidth = MeasureSpec.getSize(widthMeasureSpec);
if (mBoundedWidth > 0 && mBoundedWidth < measuredWidth) {
int measureMode = MeasureSpec.getMode(widthMeasureSpec);
widthMeasureSpec = MeasureSpec.makeMeasureSpec(mBoundedWidth, measureMode);
}
// Adjust height as necessary
int measuredHeight = MeasureSpec.getSize(heightMeasureSpec);
if (mBoundedHeight > 0 && mBoundedHeight < measuredHeight) {
int measureMode = MeasureSpec.getMode(heightMeasureSpec);
heightMeasureSpec = MeasureSpec.makeMeasureSpec(mBoundedHeight, measureMode);
}
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
RevealFrameLayout class:
public class RevealFrameLayout extends FrameLayout implements RevealAnimator{
private Path mRevealPath;
private final Rect mTargetBounds = new Rect();
private RevealInfo mRevealInfo;
private boolean mRunning;
private float mRadius;
public RevealFrameLayout(Context context) {
this(context, null);
}
public RevealFrameLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public RevealFrameLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mRevealPath = new Path();
}
#Override
public void onRevealAnimationStart() {
mRunning = true;
}
#Override
public void onRevealAnimationEnd() {
mRunning = false;
invalidate(mTargetBounds);
}
#Override
public void onRevealAnimationCancel() {
onRevealAnimationEnd();
}
#Override
public void setRevealRadius(float radius){
mRadius = radius;
mRevealInfo.getTarget().getHitRect(mTargetBounds);
invalidate(mTargetBounds);
}
#Override
public float getRevealRadius(){
return mRadius;
}
#Override
public void attachRevealInfo(RevealInfo info) {
mRevealInfo = info;
}
#Override
public SupportAnimator startReverseAnimation() {
if(mRevealInfo != null && mRevealInfo.hasTarget() && !mRunning) {
return ViewAnimationUtils.createCircularReveal(mRevealInfo.getTarget(),
mRevealInfo.centerX, mRevealInfo.centerY,
mRevealInfo.endRadius, mRevealInfo.startRadius);
}
return null;
}
#Override
protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
if(mRunning && child == mRevealInfo.getTarget()){
final int state = canvas.save();
mRevealPath.reset();
mRevealPath.addCircle(mRevealInfo.centerX, mRevealInfo.centerY, mRadius, Path.Direction.CW);
canvas.clipPath(mRevealPath);
boolean isInvalided = super.drawChild(canvas, child, drawingTime);
canvas.restoreToCount(state);
return isInvalided;
}
return super.drawChild(canvas, child, drawingTime);
}
}

How to add a custom view in another custom view in Android?

I want to create a custom view which should be added in another custom view.
The second view will be a container, so it should be able to contain the first view as its child.
For creating this views I am extending ViewGroup & LinearLayout classes.
Child view class is NodeView
public class NodeView extends LinearLayout
{
private final static String TAG = "NodeView";
private ImageView ivTop;
private ImageView ivBottom;
private Context myContext;
public NodeView(Context context, AttributeSet attrs)
{
super(context, attrs);
this.myContext = context;
setOrientation(LinearLayout.VERTICAL);
setGravity(Gravity.CENTER);
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.view_test_multi, this, true);
ivTop = (ImageView) getChildAt(0);
ivBottom = (ImageView) getChildAt(2);
ivTop.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
Toast.makeText(myContext, "Top Clicked", Toast.LENGTH_SHORT).show();
}
});
ivBottom.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
Toast.makeText(myContext, "Bottom Clicked", Toast.LENGTH_SHORT).show();
}
});
}
#Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
}
public NodeView(Context context)
{
this(context, null);
}
}
& the container class is TreeViewGroup
public class TreeViewGroup extends ViewGroup
{
private static final String TAG = "CustomTreeNodeView";
NodeView nodeView;
public TreeViewGroup(Context context, AttributeSet attrs, int defStyleAttr)
{
super(context, attrs, defStyleAttr);
nodeView = new NodeView(getContext());
addView(nodeView);
}
public TreeViewGroup(Context context, AttributeSet attrs)
{
this(context, attrs, 0);
}
public TreeViewGroup(Context context)
{
this(context, null, 0);
}
#Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b)
{
}
}
& xml layout for node view is view_test_multi.xml
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android" >
<ImageView
android:layout_width="15dp"
android:layout_height="15dp"
android:layout_centerVertical="true"
android:src="#drawable/point_grey" />
<ImageView
android:layout_width="35dp"
android:layout_height="35dp"
android:layout_centerVertical="true"
android:src="#drawable/point_red" />
<ImageView
android:layout_width="15dp"
android:layout_height="15dp"
android:layout_centerVertical="true"
android:src="#drawable/point_grey" />
</merge>
My activity's layout is activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:custom="http://schemas.android.com/apk/res/com.ab1209.testcustom"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<com.ab1209.testcustom.view.TreeViewGroup
android:id="#+id/activity_main_custom_tree_node_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
MainActivity class is
**public class MainActivity extends Activity
{
TreeViewGroup treeNodeView;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
treeNodeView = (TreeViewGroup) findViewById(R.id.activity_main_custom_tree_node_view);
}
}**
When I run the app I don't see the NodeView added in main View. Am I doing the right thing if not please tell me how can I make it working?

To create a custom ViewGroup, the only method you need to override is
onLayout. The onLayout is triggered after the ViewGroup itself has
finished laying itself out inside its own container ViewGroup and is
now responsible for laying out its children. It should call the layout
method on all of its children to now position and size them (the left
and top parameters will determine the child view’s x and y and the
right and bottom will determine its width (right – left) and height
(top-bottom).
So your TreeViewGroup code will look like :
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int count = getChildCount();
for (int i = 0; i < count; i++) {
View child = getChildAt(i);
if (child.getVisibility() != GONE) {
ViewGroup.LayoutParams lp = (ViewGroup.LayoutParams) child
.getLayoutParams();
int childLeft = 0;
int childTop = 0;
child.layout(childLeft, childTop,
childLeft + child.getMeasuredWidth(),
childTop + child.getMeasuredHeight());
}
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
measureChildren(widthMeasureSpec, heightMeasureSpec);
int measuredWidth = 200; // Calculate the height
int measuredHeight = 200; // Calculate the width
setMeasuredDimension(measuredWidth, measuredHeight);
}
Refer this link http://arpitonline.com/2012/07/01/creating-custom-layouts-for-android/

How to pass variables to custom View before onDraw() is called?

What I am trying to achieve:
measure a container View in my layout, mainContainer, that is defined in the XML
pass the mainContainer's width and height to a different custom View before onDraw() is called
I want to pass the width and height so the custom View knows where to draw canvas.drawBitmap using coordinates
The custom view will be programmatically created from code
How can I pass the measured int width and int height to my custom View before onDraw() is called?
Custom View
public class AvatarView extends ImageView {
private Bitmap body;
private Bitmap hat;
public AvatarView(Context context) {
super(context);
init();
}
public AvatarView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public AvatarView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
body = BitmapFactory.decodeResource(getResources(), R.drawable.battle_run_char);
hat = BitmapFactory.decodeResource(getResources(), R.drawable.red_cartoon_hat);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawBitmap(body, x, y, null);
canvas.drawBitmap(hat, x, y, null);
}
}
Fragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_customize_avatar, container, false);
final RelativeLayout mainContainer = (RelativeLayout) view.findViewById(R.id.main_container);
TwoWayView inventoryList = (TwoWayView) view.findViewById(R.id.inventory);
inventoryList.setAdapter(null);
inventoryList.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
}
});
mainContainer.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#SuppressLint("NewApi")
#SuppressWarnings("deprecation")
#Override
public void onGlobalLayout() {
// Retrieve the width and height
containerWidth = mainContainer.getWidth();
containerHeight = mainContainer.getHeight();
// Remove global listener
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN)
mainContainer.getViewTreeObserver().removeOnGlobalLayoutListener(this);
else
mainContainer.getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
});
return view;
}
XML
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:clickable="true"
android:background="#fff" >
<com.walintukai.lfdate.CustomTextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:textStyle="bold"
android:textColor="#fff"
android:textSize="20sp"
android:textAllCaps="true"
android:text="#string/customize_avatar"
android:background="#009BFF" />
<RelativeLayout
android:id="#+id/main_container"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<org.lucasr.twowayview.TwoWayView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/inventory"
style="#style/HorizontalListView"
android:layout_width="match_parent"
android:layout_height="80dp"
android:drawSelectorOnTop="false"
android:background="#f3f3f3" />
</LinearLayout>

What you need to do is add a flag inside your AvatarView that checks if are you going to render this or not in your onDraw method.
sample:
public class AvatarView extends ImageView {
private Bitmap body;
private Bitmap hat;
private int containerHeight;
private int containerWidth;
private boolean isRender = false;
public AvatarView(Context context) {
super(context);
init();
}
public AvatarView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public AvatarView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
public void setMeasure(int containerWidth, int containerHeight )
{
this.containerHeight = containerHeight;
this.containerWidth = containerWidth;
}
private void init() {
body = BitmapFactory.decodeResource(getResources(), R.drawable.battle_run_char);
hat = BitmapFactory.decodeResource(getResources(), R.drawable.red_cartoon_hat);
}
public void setRender(boolean render)
{
isRender = render;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if(isRender )
{
canvas.drawBitmap(body, x, y, null);
canvas.drawBitmap(hat, x, y, null);
}
}
}
Now it wont render when you dont call setRender and set it to true. And just call setMeasure to pass the value.
First you need to call setMeasure and after you set the measure you then call setRender(true) and call invalidate() to call the onDraw method to render the images

listening to scroll events horizontalscrollview android

I am trying to listen to the event when the HorizontalScrollView is scrolled. Tried this but it does not print anything.
HorizontalScrollView headerScrollView = new HorizontalScrollView(this);
headerScrollView.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
Log.i("hv1",event.toString());
Log.i("hv1","HELLO");
return false;
}
});
The actual problem is, I want to scroll two HorizontalScrollView at a time..ie; both of them need to scroll simultaneously when atleast one of them scrolled.
any workaround?
I used the answer below and then tried implementing this but I am not sure how I need to use the methods in the class.
TestHorizontalScrollView headerScrollView = (TestHorizontalScrollView) findViewById(R.id.headerHv);
Is this the way I need to point to the hsv element in the layout file?

You may want to try creating your own custom class that extends HorizontalScrollView and overriding the onScrollChanged() function as such
public class TestHorizontalScrollView extends HorizontalScrollView {
public TestHorizontalScrollView(Context context) {
super(context);
}
#Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
// TODO Auto-generated method stub
Log.i("Scrolling", "X from ["+oldl+"] to ["+l+"]");
super.onScrollChanged(l, t, oldl, oldt);
}
}
This overriden function will catch all changes to the scroll position even when the view is not being touched. This should keep your scroll views in sync.

old question, but maybe helpful. You can do something like this:
scrollOne = (HorizontalScrollView)findViewById(R.id.horizontal_one);
scrollTwo = (HorizontalScrollView)findViewById(R.id.horizontal_two);
scrollTwo.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View view, MotionEvent event) {
// TODO Auto-generated method stub
int scrollX = view.getScrollX();
int scrollY = view.getScrollY();
scrollOne.scrollTo(scrollX, scrollY);
return false;
}
});

ScrollView with Listener, api < 23
write below in your code
MyHorizontalScrollView scrollView = (MyHorizontalScrollView)view.findViewById(R.id.scrollViewBrowse);
scrollView.setOnScrollChangedListener(new MyHorizontalScrollView.OnScrollChangedListener() {
#Override
public void onScrollChanged(int l, int t, int oldl, int oldt) {
}
});
MyHorizontalScrollView
public class MyHorizontalScrollView extends ScrollView {
public OnScrollChangedListener mOnScrollChangedListener;
public MyHorizontalScrollView(Context context) {
super(context);
}
public MyHorizontalScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyHorizontalScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (mOnScrollChangedListener != null) {
mOnScrollChangedListener.onScrollChanged(l, t, oldl, oldt);
}
}
public void setOnScrollChangedListener(OnScrollChangedListener onScrollChangedListener){
this.mOnScrollChangedListener = onScrollChangedListener;
}
public interface OnScrollChangedListener{
void onScrollChanged(int l, int t, int oldl, int oldt);
}
}
* Xml file *
<MyHorizontalScrollView
android:id="#+id/scrollViewBrowse"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:background="#drawable/backgroung"
android:padding="10dp">
</MyHorizontalScrollView>

To Avoid the the Api Level Problem... follow this.
scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {
#Override
public void onScrollChanged() {
int scrollY = scrollView.getScrollY();
int scrollX = scrollView.getScrollX();
if (scrollY > 500) {
} else {
}
}
});

you can try this, i've tried so many ways, but none of them meet my needs, and then i tried to do it myself, and i succeed , and it seems good , it's smooth.
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<com.szl.fundlistdemo.WrapContentListView
android:id="#+id/left_lv"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:scrollbars="none"/>
<HorizontalScrollView
android:id="#+id/hscrollview"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<com.szl.fundlistdemo.WrapContentListView
android:id="#+id/right_lv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</HorizontalScrollView>
</LinearLayout>
</ScrollView>
public class WrapContentListView extends ListView{
public WrapContentListView(Context context) {
super(context);
}
public WrapContentListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public WrapContentListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}

Based #Dipak's answer In kotlin:
binding.scrollList.viewTreeObserver.addOnScrollChangedListener {
val X = binding.scrollList.scrollX
val Y = binding.scrollList.scrollY
}