Develop Reference

Android: How to detect if a point in the line drawn by canvas?

The line is drawn with a color which is different from the background color. Then put the bitmap in canvas in an array. If the color of the given point in the array is the same as line's color, then the point is in the line. In addition, I do not want to display the canvas in my app.
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private Button btnCheck;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnCheck = (Button) findViewById(R.id.btn_check);
btnCheck.setOnClickListener(click);
}
private View.OnClickListener click = new View.OnClickListener() {
#Override
public void onClick(View v) {
int width = 60, height =60;
int startX = 15, startY = 8;
int stopX = 15, stopY = 20;
Paint paint = new Paint();
paint.setStrokeWidth(5);
paint.setColor(Color.RED);
Bitmap baseBitmap;
Canvas canvas;
baseBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
canvas = new Canvas(baseBitmap);
canvas.drawColor(Color.WHITE);
canvas.drawLine(startX, startY, stopX, stopY, paint);
int[] arrImage = new int[width*height];
baseBitmap.setPixels(arrImage, 0, width, 0, 0, width, height);
int[][] points = new int[][]{
{15, 8},{15, 10},
{30, 30},{40, 40}};
String result = "";
for (int i=0; i<points.length; ++i) {
int index = getPixelIndex(width, points[i][0], points[i][1]);
result = result + ":" + (arrImage[index] == Color.RED);
}
Toast.makeText(MainActivity.this, result, Toast.LENGTH_LONG).show();
}
};
public int getPixelIndex(int imageWidth, int pos_x, int pos_y) {
return pos_y * imageWidth + pos_x;
}
}
But the four results are all false which is not the results I expected.
What are the errors for my code?

Your problem is this line:
baseBitmap.setPixels(arrImage, 0, width, 0, 0, width, height);
The setPixels() method replaces the pixel data in the Bitmap with the passed array, which, in this case, is all zeroes. It does not change the array's values, so they will still be all zeroes when you do your comparisons.
You want the getPixels() method instead.

Android CoverFlow is not work perfactly in SONY S tablet with same code

I am trying to implement the CoverFlow. Using the same code in other devices looks perfect but in SONY S Tablet its not looking propering. I attached below screenshot of SONY S. I have used Android 4.0 in my demo.
I am not able to understand the problem. Is is device oriented or is any problem in my code?
If anyone can understand then please let me know.
Thanks in advance.
My code below
public class CoverFlowExample extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
CoverFlow coverFlow;
coverFlow = new CoverFlow(this);
coverFlow.setAdapter(new ImageAdapter(this));
ImageAdapter coverImageAdapter = new ImageAdapter(this);
coverImageAdapter.createReflectedImages();
coverFlow.setAdapter(coverImageAdapter);
coverFlow.setSpacing(-50);
coverFlow.setSelection(8, true);
setContentView(coverFlow);
//Use this if you want to use XML layout file
//setContentView(R.layout.main);
//coverFlow = (CoverFlow) findViewById(R.id.coverflow);
}
public class ImageAdapter extends BaseAdapter
{
int mGalleryItemBackground;
private Context mContext;
// private FileInputStream fis;
private Integer[] mImageIds =
{
R.drawable.kasabian_kasabian,
R.drawable.starssailor_silence_is_easy,
R.drawable.killers_day_and_age,
R.drawable.garbage_bleed_like_me,
R.drawable.death_cub_for_cutie_the_photo_album,
R.drawable.kasabian_kasabian,
R.drawable.massive_attack_collected,
R.drawable.muse_the_resistance,
R.drawable.starssailor_silence_is_easy
};
private ImageView[] mImages;
public ImageAdapter(Context c)
{
mContext = c;
mImages = new ImageView[mImageIds.length];
}
public boolean createReflectedImages()
{
//The gap we want between the reflection and the original image
final int reflectionGap = 4;
int index = 0;
for (int imageId : mImageIds)
{
Bitmap originalImage = BitmapFactory.decodeResource(getResources(),
imageId);
int width = originalImage.getWidth();
int height = originalImage.getHeight();
//This will not scale but will flip on the Y axis
Matrix matrix = new Matrix();
matrix.preScale(1, -1);
//Create a Bitmap with the flip matrix applied to it.
//We only want the bottom half of the image
Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, height/2, width, height/2, matrix, false);
//Create a new bitmap with same width but taller to fit reflection
Bitmap bitmapWithReflection = Bitmap.createBitmap(width
, (height + height/2), Config.ARGB_8888);
//Create a new Canvas with the bitmap that's big enough for
//the image plus gap plus reflection
Canvas canvas = new Canvas(bitmapWithReflection);
//Draw in the original image
canvas.drawBitmap(originalImage, 0, 0, null);
//Draw in the gap
Paint deafaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint);
//Draw in the reflection
canvas.drawBitmap(reflectionImage,0, height + reflectionGap, null);
//Create a shader that is a linear gradient that covers the reflection
Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0, originalImage.getHeight(), 0,
bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff,
TileMode.CLAMP);
//Set the paint to use this shader (linear gradient)
paint.setShader(shader);
//Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
//Draw a rectangle using the paint with our linear gradient
canvas.drawRect(0, height, width,
bitmapWithReflection.getHeight() + reflectionGap, paint);
ImageView imageView = new ImageView(mContext);
imageView.setImageBitmap(bitmapWithReflection);
imageView.setLayoutParams(new CoverFlow.LayoutParams(120, 180));
imageView.setScaleType(ScaleType.MATRIX);
mImages[index++] = imageView;
}
return true;
}
public int getCount() {
return mImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
//Use this code if you want to load from resources
//ImageView i = new ImageView(mContext);
//i.setImageResource(mImageIds[position]);
//i.setLayoutParams(new CoverFlow.LayoutParams(130, 130));
//i.setScaleType(ImageView.ScaleType.MATRIX);
//return i;
return mImages[position];
}
/** Returns the size (0.0f to 1.0f) of the views
* depending on the 'offset' to the center. */
public float getScale(boolean focused, int offset) {
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float)Math.pow(2, Math.abs(offset)));
}
}
}
Output in SONY S

you need to call child.invalidate() in offsetChildrenLeftAndRight() method. Or where you are setting your imageview to center child call this method.

Add ImageView dynamically to View

I am making an Android game which uses the View class and I am not using an XML-layout.
All my images are drawn with canvas. Now my problem is the I cannot use a bitmap.
I am trying to add an ImageView dynamically to my View class, to use the touchable event.
Why dynamically? Because I could not use XML-layout.
Here is my code:
package com.example.poolmaster;
import java.util.ArrayList;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.Gravity;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class MainActivity extends Activity {
private int cuePosx, cuePosy;
int cueHeight, cueWeight;
double rotatingAngle;
int height;
int wwidth;
int cueHeight2, cueWeight2;
Bitmap table, stick, raise;
ImageView button = new ImageView(this);
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
rotatingAngle = 0;
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
height = displaymetrics.heightPixels;
wwidth = displaymetrics.widthPixels;
cueHeight2 = height / 2;
cueWeight2 = wwidth / 2;
System.out.println("**************************************");
System.out.println("height " + height);
System.out.println("weight" + wwidth);
System.out.println("**************************************");
// Set generic layout parameters
GamePlay custom = new GamePlay(this);
setContentView(custom);
// setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_MOVE){
// cuePosy += 10;
// System.out.println("xCORDİNATES!!!! " +ev.getX());
// System.out.println("yCORDİNATES!!!! " +ev.getY());
rotatingAngle=getAngle(ev.getX(), ev.getY());
System.out.println("Angle " +rotatingAngle);
}
if (ev.getAction()==MotionEvent.ACTION_DOWN){
System.out.println("****************** ACTİON DOWN ****************");
// cueHeight2 += 10;
// cueWeight2 += 20;
// cuePosy = 320;
}
if (ev.getAction()==MotionEvent.ACTION_UP){
System.out.println("****************** ACTİON DOWN ****************");
// cueHeight2 -= 10;
// cueWeight2 -= 20;
// cuePosy = 320;
}
return true;
}
private double getAngle(double xTouch, double yTouch) {
double theta;
theta = Math.toDegrees(Math.atan2(height / 2 - yTouch, xTouch - wwidth / 2));
return theta;
}
public class GamePlay extends View {
public GamePlay(Context context) {
super(context);
// TODO Auto-generated constructor stub
table = BitmapFactory.decodeResource(getResources(), R.drawable.bg);
table = Bitmap.createScaledBitmap(table, wwidth, height, true);
stick = BitmapFactory.decodeResource(getResources(), R.drawable.stick);
raise = BitmapFactory.decodeResource(getResources(), R.drawable.raise);
cueHeight = stick.getHeight();
System.out.println("ıstaka " + cueHeight);
cueWeight = stick.getWidth();
cuePosx = wwidth / 2;
cuePosy = height - cueHeight - 180;
}
#SuppressLint({ "DrawAllocation", "DrawAllocation" })
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
Matrix matrix = new Matrix();
matrix.setTranslate(cueWeight2, cueHeight2);
matrix.postRotate((float)rotatingAngle, cueWeight2, cueHeight2); // anti-clockwise by 90 degrees
// create a new bitmap from the original using the matrix to transform the result
Bitmap rotatedBitmap = Bitmap.createBitmap(stick, 0, 0, stick.getWidth(), stick.getHeight(), matrix, false);
canvas.save(); // Save the position of the canvas.
canvas.restore();
// Rotate the canvas.
canvas.drawBitmap(table, 0, 0, null); // Draw the ball on the rotated canvas.
canvas.drawBitmap(stick, matrix, null);
canvas.drawBitmap(raise, 0, 0, null);
invalidate();
}
}
}

This is for adding imageview to a layout where Activity class is extended
LinearLayout lL = findViewById(R.id.xmlfile_layout_id);
ImageView imgView = new ImageView(context);
imgView.setVisibility(View.VISIBLE);
lL.addView(imgView);
This is for adding imageview to a canvas where View class is extended
Initially, you cannot place any imageview, edit text or buttons using canvas. Instead, you have to draw it. So create a custom layout and draw that layout with canvas
Try this, It might help you. in onDraw(..)
LinearLayout lL = new LinearLayout(context);
ImageView imgView = new ImageView(context);
imgView.setVisibility(View.VISIBLE);
lL.addView(imgView);
lL.measure(canvas.getWidth(), canvas.getHeight());
lL.layout(0, 0, canvas.getWidth(), canvas.getHeight());
// placing the edit text at specific co-ordinates:
//canvas.translate(0, 0);
layout.draw(canvas);
And take a look at this another example : Click here
It gives another way of adding views

Use below code for that.
For Create ImageView Dynamically
ImageView mImgView1 = new ImageView(this);
For Add into your View write below code before setContentView(custom); (If GamePlay is your View Class)
custom.add(mImgView1);

Coverview widget in .xml (android)

Coverview is a widget ive implemented from http://www.inter-fuser.com/2010/02/android-coverflow-widget-v2.html and it works until i want to use it .xml instead to add buttons and stuff. I have no idea how to link the two and any help would be really appreciated
My main activity:
package cover.flow.test;
import java.io.FileInputStream;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
public class CoverFlowExampleActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
CoverFlow coverFlow;
coverFlow = new CoverFlow(this);
coverFlow.setAdapter(new ImageAdapter(this));
ImageAdapter coverImageAdapter = new ImageAdapter(this);
//coverImageAdapter.createReflectedImages();
coverFlow.setAdapter(coverImageAdapter);
coverFlow.setSpacing(-25);
coverFlow.setSelection(4, true);
coverFlow.setAnimationDuration(1000);
setContentView(coverFlow);
}
public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private FileInputStream fis;
private Integer[] mImageIds = {
R.drawable.kasabian_kasabian,
R.drawable.starssailor_silence_is_easy,
R.drawable.killers_day_and_age,
R.drawable.garbage_bleed_like_me,
R.drawable.death_cub_for_cutie_the_photo_album,
R.drawable.kasabian_kasabian,
R.drawable.massive_attack_collected,
R.drawable.muse_the_resistance,
R.drawable.starssailor_silence_is_easy
};
private ImageView[] mImages;
public ImageAdapter(Context c) {
mContext = c;
mImages = new ImageView[mImageIds.length];
}
public boolean createReflectedImages() {
//The gap we want between the reflection and the original image
final int reflectionGap = 4;
int index = 0;
for (int imageId : mImageIds) {
Bitmap originalImage = BitmapFactory.decodeResource(getResources(),
imageId);
int width = originalImage.getWidth();
int height = originalImage.getHeight();
//This will not scale but will flip on the Y axis
Matrix matrix = new Matrix();
matrix.preScale(1, -1);
//Create a Bitmap with the flip matrix applied to it.
//We only want the bottom half of the image
Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, height/2, width, height/2, matrix, false);
//Create a new bitmap with same width but taller to fit reflection
Bitmap bitmapWithReflection = Bitmap.createBitmap(width
, (height + height/2), Config.ARGB_8888);
//Create a new Canvas with the bitmap that's big enough for
//the image plus gap plus reflection
Canvas canvas = new Canvas(bitmapWithReflection);
//Draw in the original image
canvas.drawBitmap(originalImage, 0, 0, null);
//Draw in the gap
Paint deafaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint);
//Draw in the reflection
canvas.drawBitmap(reflectionImage,0, height + reflectionGap, null);
//Create a shader that is a linear gradient that covers the reflection
Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0, originalImage.getHeight(), 0,
bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff,
TileMode.CLAMP);
//Set the paint to use this shader (linear gradient)
paint.setShader(shader);
//Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
//Draw a rectangle using the paint with our linear gradient
canvas.drawRect(0, height, width,
bitmapWithReflection.getHeight() + reflectionGap, paint);
ImageView imageView = new ImageView(mContext);
imageView.setImageBitmap(bitmapWithReflection);
imageView.setLayoutParams(new CoverFlow.LayoutParams(120, 180));
imageView.setScaleType(ScaleType.MATRIX);
mImages[index++] = imageView;
}
return true;
}
public int getCount() {
return mImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
//Use this code if you want to load from resources
ImageView i = new ImageView(mContext);
i.setImageResource(mImageIds[position]);
i.setLayoutParams(new CoverFlow.LayoutParams(130, 130));
i.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
//Make sure we set anti-aliasing otherwise we get jaggies
BitmapDrawable drawable = (BitmapDrawable) i.getDrawable();
drawable.setAntiAlias(true);
return i;
//return mImages[position];
}
/** Returns the size (0.0f to 1.0f) of the views
* depending on the 'offset' to the center. */
public float getScale(boolean focused, int offset) {
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float)Math.pow(2, Math.abs(offset)));
}
}
}
My main.xml (this is what ive tries to link but with no luck)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<cover.flow.test.CoverFlow
android:id="#+id/coverflow"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/button1"
android:layout_alignParentTop="true" />
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="Button" />

To link with the view you need something like
setContentView(R.layout.main);
and remove the code creating the CoverFlow instance (instead get it with findViewById, etc.)

image adapter for coverflow

These are the activity and Image Adapter that I used for my CoverFlow. But I want to load all the images that I have saved in an sd card directory with this cover flow. How Can I do that? I have saved my images in an sd card directory called All. I want to load images from that folder. Any help is appreciated.
public class CoverFlowExample extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
CoverFlow coverFlow;
coverFlow = new CoverFlow(this);
coverFlow.setAdapter(new ImageAdapter(this));
ImageAdapter coverImageAdapter = new ImageAdapter(this);
coverImageAdapter.createReflectedImages();
coverFlow.setAdapter(coverImageAdapter);
coverFlow.setSpacing(-15);
coverFlow.setSelection(8, true);
setContentView(coverFlow);
//Use this if you want to use XML layout file
//setContentView(R.layout.main);
//coverFlow = (CoverFlow) findViewById(R.id.coverflow);
}
public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private FileInputStream fis;
private Integer[] mImageIds = {
R.drawable.top,
R.drawable.bottom,
R.drawable.top,
R.drawable.bottom,
R.drawable.top,
R.drawable.bottom,
R.drawable.top,
R.drawable.bottom,
R.drawable.top
};
private ImageView[] mImages;
public ImageAdapter(Context c) {
mContext = c;
mImages = new ImageView[mImageIds.length];
}
public boolean createReflectedImages() {
//The gap we want between the reflection and the original image
final int reflectionGap = 7;
int index = 0;
for (int imageId : mImageIds) {
Bitmap originalImage = BitmapFactory.decodeResource(getResources(),
imageId);
int width = originalImage.getWidth();
int height = originalImage.getHeight();
//This will not scale but will flip on the Y axis
Matrix matrix = new Matrix();
matrix.preScale(1, -1);
//Create a Bitmap with the flip matrix applied to it.
//We only want the bottom half of the image
Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, height/2, width, height/2, matrix, false);
//Create a new bitmap with same width but taller to fit reflection
Bitmap bitmapWithReflection = Bitmap.createBitmap(width
, (height + height/2), Config.ARGB_8888);
//Create a new Canvas with the bitmap that's big enough for
//the image plus gap plus reflection
Canvas canvas = new Canvas(bitmapWithReflection);
//Draw in the original image
canvas.drawBitmap(originalImage, 0, 0, null);
//Draw in the gap
Paint deafaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint);
//Draw in the reflection
canvas.drawBitmap(reflectionImage,0, height + reflectionGap, null);
//Create a shader that is a linear gradient that covers the reflection
Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0, originalImage.getHeight(), 0,
bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff,
TileMode.CLAMP);
//Set the paint to use this shader (linear gradient)
paint.setShader(shader);
//Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
//Draw a rectangle using the paint with our linear gradient
canvas.drawRect(0, height, width,
bitmapWithReflection.getHeight() + reflectionGap, paint);
ImageView imageView = new ImageView(mContext);
imageView.setImageBitmap(bitmapWithReflection);
imageView.setLayoutParams(new CoverFlow.LayoutParams(120, 180));
imageView.setScaleType(ScaleType.MATRIX);
mImages[index++] = imageView;
}
return true;
}
public int getCount() {
return mImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
//Use this code if you want to load from resources
// ImageView i = new ImageView(mContext);
//i.setImageResource(mImageIds[position]);
//i.setLayoutParams(new CoverFlow.LayoutParams(130, 130));
//i.setScaleType(ImageView.ScaleType.MATRIX);
//return i;
return mImages[position];
}
/** Returns the size (0.0f to 1.0f) of the views
* depending on the 'offset' to the center. */
public float getScale(boolean focused, int offset) {
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float)Math.pow(2, Math.abs(offset)));
}
}
}

To know what files you want to load you can use (new File("/sdcard/All")).list(). To convert all those files to Bitmap you can use BitmapFactory.decodeFile(String pathName).