Develop Reference

Android Studio: Create Object in custom SwipeButton with attributes from XML

public class SwipeButton extends RelativeLayout {
private ImageView swipeButtonInner;
private float initialX;
private boolean active;
private TextView centerText;
private ViewGroup background;
private Drawable disabledDrawable;
private Drawable enabledDrawable;
private OnStateChangeListener onStateChangeListener;
private OnActiveListener onActiveListener;
private static final int ENABLED = 0;
private static final int DISABLED = 1;
private int collapsedWidth;
private int collapsedHeight;
private LinearLayout layer;
private boolean trailEnabled = false;
private boolean hasActivationState;
public SwipeButton(Context context) {
super(context);
init(context, null, -1, -1);
}
public SwipeButton(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs, -1, -1);
}
public SwipeButton(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context, attrs, defStyleAttr, -1);
}
#TargetApi(21)
public SwipeButton(Context context, AttributeSet attrs, int defStyleAttr, int
defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
init(context, attrs, defStyleAttr, defStyleRes);
}
public boolean isActive() {
return active;
}
public void setText(String text) {
centerText.setText(text);
}
public void setBackground(Drawable drawable) {
background.setBackground(drawable);
}
public void setSlidingButtonBackground(Drawable drawable) {
background.setBackground(drawable);
}
public void setDisabledDrawable(Drawable drawable) {
disabledDrawable = drawable;
if (!active) {
swipeButtonInner.setImageDrawable(drawable);
}
}
public void setButtonBackground(Drawable buttonBackground) {
if (buttonBackground != null) {
swipeButtonInner.setBackground(buttonBackground);
}
}
public void setEnabledDrawable(Drawable drawable) {
enabledDrawable = drawable;
if (active) {
swipeButtonInner.setImageDrawable(drawable);
}
}
public void setOnStateChangeListener(OnStateChangeListener
onStateChangeListener) {
this.onStateChangeListener = onStateChangeListener;
}
public void setOnActiveListener(OnActiveListener onActiveListener) {
this.onActiveListener = onActiveListener;
}
public void setInnerTextPadding(int left, int top, int right, int bottom) {
centerText.setPadding(left, top, right, bottom);
}
public void setSwipeButtonPadding(int left, int top, int right, int bottom) {
swipeButtonInner.setPadding(left, top, right, bottom);
}
public void setHasActivationState(boolean hasActivationState) {
this.hasActivationState = hasActivationState;
}
My XML:`
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:id="#+id/AnswerRelativeLayout"
android:layout_height="70dp"
android:orientation="vertical"
tools:context="com.example.dynamicobj.FragmentMain">
<com.example.dynamicobj.SwipeButton
android:id="#+id/test_btn"
android:layout_width="match_parent"
android:layout_height="70dp"
app:button_background="#drawable/shape_button"
app:button_image_disabled="#drawable/ic_launcher_background"
app:button_image_height="60dp"
app:button_image_width="100dp"
app:has_activate_state="true"
app:initial_state="disabled"
app:inner_text="Termine buchen"
app:inner_text_background="#drawable/shape_rounded"
app:inner_text_bottom_padding="18dp"
app:inner_text_right_padding="200dp"
app:inner_text_color="#android:color/black"
app:inner_text_size="16sp"
app:inner_text_top_padding="18dp" />
</LinearLayout>`
F
ragmentMain:
public class FragmentMain extends Fragment {
Context context;
View rootView;
public FragmentMain() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(false);
}
#Override
public View onCreateView(final LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_main, container, false);
LinearLayout layout = (LinearLayout)
rootView.findViewById(R.id.AnswerRelativeLayout);
SwipeButton button = new SwipeButton(getContext());
layout.addView(button);
return rootView;
}
}
So I got this custom SwipeButton class from Git (com.ebanx.swipebtn.SwipeButton). Now I want to create an Object from SwipeButton with a layout looking like the one from the xml file. Is there any method, where I just can give the new button the prefinished layout without having to use all these Methods in the SwipeButton class? I am going to create the buttons dynamically later on, but all being the same layout. Help pls?

you forgot to add LayoutParams to your button
use below code before adding button into layout
button.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT))
and set your LinearLayout height wrap_content not 70dp

Getting null pointer exception when using getLayoutParams()

I have a custom ImageView class (I don't think the code in the class matters but I'll include it here anyway incase it is needed):
package com.example.vroy.customcirclebuttontest;
import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;
public class CircleButton extends ImageView {`
private int radius;
private int x;
private int y;
public CircleButton(Context context) {
super(context);
constructorTask();
}
public CircleButton(Context context, AttributeSet attrs) {
super(context, attrs);
constructorTask();
}
public CircleButton(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
constructorTask();
}
public CircleButton(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
constructorTask();
}
private void constructorTask() {
x = 300;
y = 300;
radius = 100;
}
#Override
public void setPressed(boolean pressed) {
super.setPressed(pressed);
Log.i("Button Logger","Button Pressed");
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(x, y, radius, GameView.green);
Log.i("Drawing status", "CircleButton Drawing..." + " " + Integer.toString(this.x) + "," + Integer.toString(this.y));
}
}
I declare a instance of this class in my activity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
testCircleButton = new CircleButton(getApplicationContext());
makeFullScreen();
testCircleButton.getLayoutParams().width = 200;
testCircleButton.getLayoutParams().height = 200;
RelativeLayout screenLayout = (RelativeLayout) findViewById(R.id.screenLayout);
screenLayout.addView(testCircleButton);
Log.i("Button Status","Adding Button To Layout");
}
However when I do this I get a "null pointer" exception.
How can I fix this?

It's because your testCircleButton is not attached to the Activity. It has no LayoutParams if it's not added to any parent.
Use
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(200, 200) // I'm not sure about constructor arguments.
testCircleButton.setLayoutParams(lp);
Use different LayoutParams if your root layout is different(FrameLayout etc).

Why I can not put and see a custom view in a layout?

Why I can not put and see a custom view in a layout?
public class MainActivity extends Activity {
A a;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
a = (A) findViewById(R.id.a);
setContentView(a);
}
class A extends View {
Paint paint;
A(Context context) {
super(context);
paint = new Paint();
}
#Override
protected void onDraw(Canvas canvas) {
paint.setAntiAlias(true);
paint.setColor(Color.RED);
canvas.drawRect(10, 20, 60, 100, paint);
}
}
}
And please see the following image:

View A is an inner class of the Activity class, so the defination in the layout file is a little different.
Use this pattern:
<view class="{package}.{ParentClass}${innerClass}" />
In your case:
<view class="com.example.tec.test.MainActivity$A" />
Notice it's lowercase "view" not "View". And the inner class A should be declared as "public static" like this:
public class MainActivity extends Activity {
// Activity's methods
public static class A extends View {
public A(Context context) {
this(context, null);
}
public A(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public A(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
// A's methods
}
}

Override the below constructor on your view class and see if it works. When you include the view in xml you need to include the xml constructor in the view.
View(Context context, AttributeSet attrs)
public A(Context context, AttributeSet attrs) {
super(context, attrs);
}
public A(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}

I solved my problem using your help.Thank you. The following code is for other questioner.
<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" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".MainActivity">
<view class="com.example.tec.test.A"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/a"
/>
</RelativeLayout>
And the following java code:
public class MainActivity extends Activity {
A a;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
a= (A) findViewById(R.id.a);
a = new A(this);
setContentView(a);
}
}
class A extends View {
Paint paint;
public A(Context context) {
super(context);
}
public A(Context context, AttributeSet attrs) {
super(context, attrs);
}
public A(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
#Override
protected void onDraw(Canvas canvas) {
paint = new Paint();
paint.setColor(Color.RED);
canvas.drawRect(10, 20, 60, 70, paint);
}
}

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

custom navigation bar android

I want to do a custom horizontal navigation bar, which consists of as many dots as i have pages.
My thoughts are:
Create a Custom ListView
Create Class Dot extends from View
Add all these dots to the custom listview dynamically..
Is this right to do so?
EDIT:
public class NavigationBarLesson extends LinearLayout {
private LessonConfig config = LessonConfig.getInstance();
private ArrayList<NavigationCircle> navigationCircles;
private int pageCount;
public NavigationBarLesson(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public NavigationBarLesson(Context context) {
super(context);
init(context);
}
private void init(Context context) {
Log.i("init","yes");
pageCount = config.getLektionCount();
navigationCircles = new ArrayList<NavigationCircle>();
for(int i=0; i < pageCount; i++){
this.addView(new NavigationCircle(context));
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int width = View.MeasureSpec.getSize(widthMeasureSpec);
int height = View.MeasureSpec.getSize(heightMeasureSpec);
setMeasuredDimension(width, height);
}
}
public class NavigationCircle extends ImageView{
private static Bitmap img;
private Bitmap activeImg;
public NavigationCircle(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
public NavigationCircle(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public NavigationCircle(Context context) {
super(context);
init();
}
public void init() {
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(0, 0, 5, 0);
this.setLayoutParams(lp);
this.setBackgroundResource(R.drawable.upcoming_pages);
}
public Bitmap getImg() {
return img;
}
public Bitmap getActiveImg() {
return this.activeImg;
}
}

Well, I do not see why you would need a ListView. Create a horizontal LinearLayout with some simple views like TextView's or ImageView's etc added dynamically to the LinearLayout.