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Color detection in android (java) delivers wrong RGB values

I am trying to make a program in Android Studio using java, where I can determine the RGB values at the point where the user clicked on the image. The code is working so far, but it gives wrong RGB values as output. They also seem to vary, based on the location where I click, even if the color that should be put out is the same. My guess is, that there is something up with the Bitmap, that I don't know about.
My MainActivity :
package com.example.fitme;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
final int evX = (int) ev.getX();
final int evY = (int) ev.getY();
switch (action) {
case MotionEvent.ACTION_DOWN :
break;
case MotionEvent.ACTION_UP :
ImageView img = (ImageView) findViewById (R.id.body_front_map);
img.setDrawingCacheEnabled(true);
Bitmap imgbmp = Bitmap.createBitmap(img.getDrawingCache());
img.setDrawingCacheEnabled(false);
int pxl = imgbmp.getPixel(evX, evY);
int redComponent = Color.red(pxl);
int greenComponent = Color.green(pxl);
int blueComponent = Color.blue(pxl);
Toast.makeText(MainActivity.this,"RED: "+redComponent+" GREEN: "+greenComponent+" BLUE: "+blueComponent, Toast.LENGTH_SHORT).show();
break;
}
return false;
}
}
XML:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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:layout_height="match_parent"
tools:context=".MainActivity">
<ImageView
android:id="#+id/body_front_map"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="visible"
android:background="#drawable/body_front_map"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
The Image I am trying to use

How to detect swipe between views to make path across them in android java?

I am trying to make game for which there are buttons with alphabets and if user swipes over them then it should detect the views as well as make a line across them. I searched many tutorials, examples and questions but unable to get the idea. I have attached image to help understand the question.
Here are the codes:
MainActivity.java
package com.example.detecttouch;
import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
TextView btn1, btn2;
TextView txtresult;
Rect outRect = new Rect();
int[] location = new int[2];
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn1 = findViewById(R.id.btn1);
btn2 = findViewById(R.id.btn2);
txtresult = (TextView) findViewById(R.id.txtresult);
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {}
});
btn1.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
int x = (int)event.getRawX();
int y = (int)event.getRawY();
if(event.getAction() == MotionEvent.ACTION_UP){
if(isViewInBounds(btn2, x, y))
btn2.dispatchTouchEvent(event);
else if(isViewInBounds(btn1, x, y)){
Log.d("Panauti", "onTouch ViewA");
//Here goes code to execute on onTouch ViewA
}
}
// Further touch is not handled
return false;
}
});
btn2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {}
});
btn2.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
int x = (int)event.getRawX();
int y = (int)event.getRawY();
if(event.getAction() == MotionEvent.ACTION_UP){
if(isViewInBounds(btn1, x, y))
btn1.dispatchTouchEvent(event);
else if(isViewInBounds(btn2, x, y)){
Log.d("Panauti", "onTouch ViewB");
//Here goes code to execute on onTouch ViewB
}
}
// Further touch is not handled
return false;
}
});
}
private boolean isViewInBounds(View view, int x, int y){
view.getDrawingRect(outRect);
view.getLocationOnScreen(location);
outRect.offset(location[0], location[1]);
return outRect.contains(x, y);
}
}
and activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/txtresult"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="102dp"
android:textColor="#android:color/holo_red_dark"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="25dp"
android:text="A" />
<TextView
android:id="#+id/btn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="160dp"
android:text="B" />
</RelativeLayout>
Please Help. Thanks in advance.

I suggest making a layout that contains the four TextViews and then setting up an onTouchListener to the layout containing them. That way, it can draw a line whenever the layout is touched rather than a specific button and can migrate between views:
private int startX, startY, endX, endY; // fields to determine the coordinates of the Rect
layout.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
startX = event.getRawX();
startY = event.getRawY();
} else {
endX = event.getRawX();
endY = event.getRawY();
// set line bounds
}
}
});

Viewpager in Dialog?

I'm trying to have a dialog where you can click a "next" button to swipe right to the next screen. I am doing that with a ViewPager and adapter:
final Dialog dialog = new Dialog(this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.voicedialog);
dialog.setCanceledOnTouchOutside(false);
MyPageAdapter adapter = new MyPageAdapter();
ViewPager pager = (ViewPager) findViewById(R.id.viewpager);
pager.setAdapter(adapter);
However, I get a NullPointerException saying that pager is null. Why is this happening? Here is the Page Adapter class:
public class MyPageAdapter extends PagerAdapter {
public Object instantiateItem(ViewGroup collection, int position) {
int resId = 0;
switch (position) {
case 0:
resId = R.id.voice1;
break;
case 1:
resId = R.id.voice2;
break;
}
return collection.findViewById(resId);
}
#Override
public int getCount() {
return 2;
}
#Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
}
Here's my layout for the DIALOG:
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
Let me know on how to avoid this situation.
PS: Each of the layouts that should be in the view pager look like this, just diff. text:
<RelativeLayout android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/voice2"
xmlns:android="http://schemas.android.com/apk/res/android">
<TextView
android:text="Slide 1!"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/textView2"
android:layout_gravity="center"
android:textSize="50sp" />
</RelativeLayout>

Without Using Enum Class
You should call findViewById on dialog. so for that you have to add dialog before findViewById..
Like this,
ViewPager pager = (ViewPager) dialog.findViewById(R.id.viewpager);
After solving your null pointer exception the other problem's solution here, if you wont use enum class you can use below code...
MainActivity.java
package demo.com.pager;
import android.app.Dialog;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
Button btn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn= (Button) findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
final Dialog dialog = new Dialog(MainActivity.this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.voicedialog);
dialog.setCanceledOnTouchOutside(false);
MyPageAdapter adapter = new MyPageAdapter(MainActivity.this);
ViewPager pager = (ViewPager) dialog.findViewById(R.id.viewpager);
pager.setAdapter(adapter);
dialog.show();
}
});
}
}
activity_main.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:id="#+id/activity_main"
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="demo.com.pager.MainActivity">
<Button
android:id="#+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!" />
</RelativeLayout>
MyPageAdapter.java
package demo.com.pager;
import android.app.FragmentManager;
import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.view.PagerAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by rucha on 26/12/16.
*/
public class MyPageAdapter extends PagerAdapter {
Context mContext;
int resId = 0;
public MyPageAdapter(Context context) {
mContext = context;
}
public Object instantiateItem(ViewGroup collection, int position) {
/* int resId = 0;
switch (position) {
case 0:
resId = R.id.voice1;
break;
case 1:
resId = R.id.voice2;
break;
}
return collection.findViewById(resId);*/
LayoutInflater inflater = LayoutInflater.from(mContext);
switch (position) {
case 0:
resId = R.layout.fragment_blue;
break;
case 1:
resId = R.layout.fragment_pink;
break;
}
ViewGroup layout = (ViewGroup) inflater.inflate(resId, collection, false);
collection.addView(layout);
return layout;
}
#Override
public int getCount() {
return 2;
}
#Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
}
FragmentBlue.java
package demo.com.pager;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import android.support.v4.app.Fragment;
public class FragmentBlue extends Fragment {
private static final String TAG = FragmentBlue.class.getSimpleName();
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_blue, container, false);
return view;
}
}
fragment_blue.xml
<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:background="#4ECDC4">
</RelativeLayout>
voicedialog.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
Please check and reply.

Using Enum Class
Try this code, This is working if any doubt ask again. Happy to help.
MainActivity.java
package demo.com.dialogdemo;
import android.app.Dialog; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.os.Bundle; import android.support.v4.view.ViewPager; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.view.Window; import android.widget.Button;
public class MainActivity extends AppCompatActivity {
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setupUIComponents();
setupListeners();
}
private void setupUIComponents() {
button = (Button) findViewById(R.id.button);
}
private void setupListeners() {
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final Dialog dialogItemDetails = new Dialog(MainActivity.this);
dialogItemDetails.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialogItemDetails.setContentView(R.layout.dialoglayout);
dialogItemDetails.getWindow().setBackgroundDrawable(
new ColorDrawable(Color.TRANSPARENT));
ViewPager viewPager = (ViewPager) dialogItemDetails.findViewById(R.id.viewPagerItemImages);
viewPager.setAdapter(new CustomPagerAdapter(MainActivity.this));
dialogItemDetails.show();
}
});
}
}
activity_main.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">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="dialog" />
</RelativeLayout>
ModelObject1.java
public enum ModelObject1 {
RED(R.string.red, R.layout.fragment_one),
BLUE(R.string.blue, R.layout.fragment_two);
private int mTitleResId;
private int mLayoutResId;
ModelObject1(int titleResId, int layoutResId) {
mTitleResId = titleResId;
mLayoutResId = layoutResId;
}
public int getTitleResId() {
return mTitleResId;
}
public int getLayoutResId() {
return mLayoutResId;
}
}
CustomPagerAdapter.java
package demo.com.dialogdemo;
import android.content.Context;
import android.support.v4.view.PagerAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by rucha on 26/12/16.
*/
public class CustomPagerAdapter extends PagerAdapter {
private Context mContext;
public CustomPagerAdapter(Context context) {
mContext = context;
}
#Override
public Object instantiateItem(ViewGroup collection, int position) {
ModelObject1 modelObject = ModelObject1.values()[position];
LayoutInflater inflater = LayoutInflater.from(mContext);
ViewGroup layout = (ViewGroup) inflater.inflate(modelObject.getLayoutResId(), collection, false);
collection.addView(layout);
return layout;
}
#Override
public void destroyItem(ViewGroup collection, int position, Object view) {
collection.removeView((View) view);
}
#Override
public int getCount() {
return ModelObject1.values().length;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
#Override
public CharSequence getPageTitle(int position) {
ModelObject1 customPagerEnum = ModelObject1.values()[position];
return mContext.getString(customPagerEnum.getTitleResId());
}
}
dailoglayout.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/txtHeaderTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:gravity="center"
android:text="ITEM IMAGES"
android:textStyle="bold" />
<android.support.v4.view.ViewPager
android:id="#+id/viewPagerItemImages"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white" />
</RelativeLayout>
fragmentone.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="one"/>
</LinearLayout>

Move Image Left & Right When it Zoomed

How to move image right to left when it zoomed ? I have done zooming on images and now don't know which codes to write for creating movement using finger once it zoomed.
Please have a look at my code and give me your precious reply. Edit my code if possible. Thanks in advance.
MainActivity.java
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.ZoomControls;
public class MainActivity extends Activity {
ImageView img;
ZoomControls zoom;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
img = (ImageView) findViewById(R.id.imageView1);
zoom = (ZoomControls) findViewById(R.id.zoomControls1);
zoom.setOnZoomInClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
int w = img.getWidth();
int h = img.getHeight();
RelativeLayout.LayoutParams params =
new RelativeLayout.LayoutParams(w + 10, h +10);
params.addRule(RelativeLayout.CENTER_IN_PARENT);
img.setLayoutParams(params);
}
});
zoom.setOnZoomOutClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
int w = img.getWidth();
int h = img.getHeight();
RelativeLayout.LayoutParams params =
new RelativeLayout.LayoutParams(w - 10, h -10);
params.addRule(RelativeLayout.CENTER_IN_PARENT);
img.setLayoutParams(params);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
activity_main.xml
<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" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="#drawable/ic_launcher" />
<ZoomControls
android:id="#+id/zoomControls1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="50dp" />

Try this library..it easy to implement and works flawlessly
Image Zoom Library

onTouchEvent does not work when the view is in a layout

I have created a class MapView that draws some circles and lines representing a map, where you can touch a circle to change the color of it. If works as it should, but when I add the View to a Layout the touchlistener does not return any touches.
Here is my MainActivity.java
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.*;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.RelativeLayout;
public class MainActivity extends Activity {
MapView mapView;
RelativeLayout mainLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mainLayout = new RelativeLayout(this);
mapView = new MapView(this);
mapView.findViewById(R.id.theMap2);
mapView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_UP) {
float x = event.getX();
float y = event.getY();
System.out.println("Touch! X: " + x + ", Y: " + y);
mapView.touched(x, y);
return true;
}
return true;
}
});
setContentView(R.layout.activity_main2);
}
I can see that the mapView works by doing this: setContentView(mapView);
Here is activity_main2.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent">
<bus.com.ece602_bus.MapView
android:id="#+id/theMap2"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
What am I doing wrong? Why are the touches not registered?

setContentView(R.layout.activity_main2); creates a new layout with a new instance of MapView than the one you set the listener for.