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Simple RecyclerView example with filter option in Android

Hi Guys, Maybe you all are expert in terms of using RecyclerView in android. This blog is simple example for using filter option with RecyclerView adapter. As for now you will instantiate RecyclerView and set the adapter to RecyclerView as following way. RecyclerView list = (RecyclerView) findViewById(R.id.list); list.setLayoutManager(new LinearLayoutManager(this)); list.setHasFixedSize(true); ArrayList&ltNumber&gt numbers = new ArrayList&lt&gt(); String ONEs[] = {"ZERO", "ONE", "TWO", "THREE", "FOUR", "FIVE", "SIX", "SEVEN", "EIGHT", "NINE", "TEN"}; String TENs[] = {"ZERO", "TEN", "TWENTY", "THIRTY", "FOURTY", "FIFTY", "SIXTY", "SEVENTY", "EIGHTY", "NINETY", "HUNDRED"}; String HUNDREDS[] = {"ZERO", "HUNDRED", "TWO HUND...
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Drawing Example in Android

Simple drawing example in android.

In Android You can draw using Canvas. First You have to get the touched points to draw. By using onTouchEvent method You can get the touched points from android device. Our onTouchEvent method will be

public boolean onTouchEvent(MotionEvent event) {
   PathWithPaint pp = new PathWithPaint();
   if (event.getAction() == MotionEvent.ACTION_DOWN) {
    path.moveTo(event.getX(), event.getY());
    path.lineTo(event.getX(), event.getY());
   } else if (event.getAction() == MotionEvent.ACTION_MOVE) {
    path.lineTo(event.getX(), event.getY());
   } else if (event.getAction() == MotionEvent.ACTION_UP) {
    path.lineTo(event.getX(), event.getY());
    mCanvas.drawPath(path, mPaint);
    pp.setPath(path);
    pp.setmPaint(mPaint);
    _graphics1.add(pp);
   }
   invalidate();
   return true;
  }

Now You are going to draw on the touched point. You have to override the onDraw method to draw on the path. The onDraw method will be like as following
  @Override
  public void onDraw(Canvas canvas) {

   canvas.drawBitmap(mBitmap, 0, 0, mPaint);

   if (_graphics1.size() > 0) {
    canvas.drawPath(_graphics1.get(_graphics1.size() - 1).getPath(), _graphics1.get(_graphics1.size() - 1).getmPaint());
   }
  }


You can use ColorPicker to get different colors.

Also you can save our drawing as .JPG file using FileOutputStream. Also you can erase previously drawn path and clear the whole drawing. And also you can set border.

Complete Code.

MainActivity.java 
package com.example.draw;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Date;

import com.example.draw.ColorPicker.OnColorChangedListener;
import android.app.Activity;
import android.app.WallpaperManager;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.RoundRectShape;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ComposePathEffect;
import android.graphics.CornerPathEffect;
import android.graphics.DiscretePathEffect;
import android.graphics.EmbossMaskFilter;
import android.graphics.LinearGradient;
import android.graphics.MaskFilter;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathEffect;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Display;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.SubMenu;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.widget.LinearLayout;
import android.widget.Toast;

public class MainActivity extends Activity implements OnColorChangedListener {

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  requestWindowFeature(Window.FEATURE_NO_TITLE);
  setContentView(R.layout.activity_main);
  
  float[] outerR = new float[] { 12, 12, 12, 12, 0, 0, 0, 0 };
  RectF inset = new RectF(6, 6, 6, 6);
  float[] innerR = new float[] { 12, 12, 0, 0, 12, 12, 0, 0 };
  
  mDrawables = new ShapeDrawable[2];
  
  mDrawables[0] = new ShapeDrawable(new RoundRectShape(outerR, inset, null));
  mDrawables[0].getPaint().setShader(makeSweep());
  
  mDrawables[1] = new ShapeDrawable(new RoundRectShape(outerR, inset, innerR));
  mDrawables[1].getPaint().setShader(makeLinear());
  
  PathEffect mPathEffect1 = new DiscretePathEffect(10, 4);
  PathEffect mPathEffect2 = new CornerPathEffect(4);
  
  mDrawables[0].getPaint().setPathEffect(new ComposePathEffect(mPathEffect2, mPathEffect1));
  LinearLayout layout = (LinearLayout) findViewById(R.id.myDrawing);
  layout.setBackgroundDrawable(mDrawables[0]);
  activity = this; 
  mView = new DrawingView(this);
  layout.addView(mView, new LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));
  
  init();
  
  mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 }, 0.4f, 6, 3.5f);
  mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);
 }

 private static Shader makeLinear() {
  return new LinearGradient(0, 0, 50, 50, new int[] { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF }, null, Shader.TileMode.MIRROR);
 }

 private static Shader makeSweep() {
  return new SweepGradient(150, 25, new int[] { 0xFFFF0000, 0xFF00FF00, 0xFF0000FF, 0xFFFF0000 }, null);
 }

 private ShapeDrawable[] mDrawables;
 private MaskFilter mEmboss;
 private MaskFilter mBlur;
 private Paint mPaint;
 Activity activity;
 View mView;

 private void init() {
  mPaint = new Paint();
  mPaint.setDither(true);
  mPaint.setColor(0xFFFFFF00);
  mPaint.setStyle(Paint.Style.STROKE);
  mPaint.setStrokeJoin(Paint.Join.ROUND);
  mPaint.setStrokeCap(Paint.Cap.ROUND);
  mPaint.setStrokeWidth(3);
 }

 class DrawingView extends View {
  private Path path;
  private Bitmap mBitmap;
  private Canvas mCanvas;
  int width, height;

  public DrawingView(Context context) {
   super(context);
   path = new Path();
   mBitmap = Bitmap.createBitmap(820, 480, Bitmap.Config.ARGB_8888);
   mCanvas = new Canvas(mBitmap);
   this.setBackgroundColor(Color.BLACK);
  }

  private ArrayList<PathWithPaint> _graphics1 = new ArrayList<PathWithPaint>();

  public boolean onTouchEvent(MotionEvent event) {
   PathWithPaint pp = new PathWithPaint();
   if (event.getAction() == MotionEvent.ACTION_DOWN) {
    path.moveTo(event.getX(), event.getY());
    path.lineTo(event.getX(), event.getY());
   } else if (event.getAction() == MotionEvent.ACTION_MOVE) {
    path.lineTo(event.getX(), event.getY());
   } else if (event.getAction() == MotionEvent.ACTION_UP) {
    path.lineTo(event.getX(), event.getY());
    mCanvas.drawPath(path, mPaint);
    pp.setPath(path);
    pp.setmPaint(mPaint);
    _graphics1.add(pp);
   }
   invalidate();
   return true;
  }

  @Override
  public void onDraw(Canvas canvas) {

   canvas.drawBitmap(mBitmap, 0, 0, mPaint);

   if (_graphics1.size() > 0) {
    canvas.drawPath(_graphics1.get(_graphics1.size() - 1).getPath(), _graphics1.get(_graphics1.size() - 1).getmPaint());
   }
   
   Display display = getWindowManager().getDefaultDisplay();
   int width = 300;
   int height = 425;
   try {
    Method mGetRawH = Display.class.getMethod("getRawHeight");
    Method mGetRawW = Display.class.getMethod("getRawWidth");
    width = (Integer) mGetRawW.invoke(display);
    height = (Integer) mGetRawH.invoke(display);
   } catch (SecurityException e) {
    e.printStackTrace();
   } catch (NoSuchMethodException e) {
    e.printStackTrace();
   } catch (IllegalArgumentException e) {
    e.printStackTrace();
   } catch (IllegalAccessException e) {
    e.printStackTrace();
   } catch (InvocationTargetException e) {
    e.printStackTrace();
   }

   int x = 0;
   int y = 0;
   if (curveDrawable == 1) {
    mDrawables[0].setBounds(x, y, x + width, (y + height) - 35);
    mDrawables[0].draw(canvas);
   }
   if (curveDrawable == 2) {
    mDrawables[1].setBounds(x, y, x + width, (y + height) - 35);
    mDrawables[1].draw(canvas);
   }
  }

  public void clearView() {
   _graphics1.removeAll(_graphics1);
   mBitmap = Bitmap.createBitmap(width, height,
     Bitmap.Config.ARGB_8888);
   mCanvas = new Canvas(mBitmap);
   path = new Path();
   invalidate();
  }

  @Override
  public void invalidate() {
   super.invalidate();
  }

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
   super.onSizeChanged(w, h, oldw, oldh);
   width = w;
   height = h;
   mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
   mCanvas = new Canvas(mBitmap);
  }

  public void colorChange() {
   path = new Path();
   invalidate();
  }

  public void saveAsJpg(File f, View v, boolean setWallpaper) {
   String fname = f.getAbsolutePath();
   FileOutputStream fos = null;
   try {
    fos = new FileOutputStream(fname);
    Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(),
      Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);
    v.draw(c);
    
    if (setWallpaper) {
     WallpaperManager myWallpaperManager = WallpaperManager
       .getInstance(getApplicationContext());
     try {
      myWallpaperManager.setBitmap(b);
     } catch (IOException e) {
      e.printStackTrace();
     }
     Toast.makeText(activity, "Wallpaper has been seted up",
       Toast.LENGTH_LONG).show();
    } else {
     b.compress(CompressFormat.JPEG, 100, fos);
     Toast.makeText(activity, "Image Saved", Toast.LENGTH_LONG)
       .show();
    }
   } catch (Exception ex) {
    Toast.makeText(activity, "Error Saving Image",
      Toast.LENGTH_LONG).show();
    Log.i("DAVE", "stacktrace is " + ex);
   }
  }
 }

 private boolean isDrawBorder = true;
 int bgcolor = Color.BLACK;

 public void colorChanged(String key, int color) {
  
  if (key.equals("")) {
   mPaint = new Paint();
   mPaint.setDither(true);
   mPaint.setColor(color);
   mPaint.setStyle(Paint.Style.STROKE);
   mPaint.setStrokeJoin(Paint.Join.ROUND);
   mPaint.setStrokeCap(Paint.Cap.ROUND);
   mPaint.setStrokeWidth(3);
  } else if (key.equals("Bg Color")) {
   if (isDrawBorder)
    ((DrawingView) mView).invalidate();
   else
    ((DrawingView) mView).clearView();
   ((DrawingView) mView).setBackgroundColor(color);
   bgcolor = color;
   isDrawBorder = false;
  }

 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  super.onCreateOptionsMenu(menu);

  menu.add(0, 0, 0, "Color").setShortcut('3', 'c');
  menu.add(0, 1, 0, "BG Color").setShortcut('3', 'c');
  menu.add(0, 2, 0, "Emboss").setShortcut('4', 's');
  menu.add(0, 3, 0, "Blur").setShortcut('5', 'z');
  menu.add(0, 4, 0, "Erase").setShortcut('5', 'z');
  menu.add(0, 5, 0, "SrcATop").setShortcut('5', 'z');
  
  SubMenu border = menu.addSubMenu(0, 9, 0, "Border");
  
  menu.add(0, 6, 0, "Set as Wallpaper").setShortcut('5', 'z');
  menu.add(0, 7, 0, "Save").setShortcut('5', 'z');
  menu.add(0, 8, 0, "Clear").setShortcut('5', 'z');

  border.add(0, 10, 0, "Curve").setShortcut('5', 'z');
  border.add(0, 11, 0, "Rectangle").setShortcut('5', 'z');
  border.add(0, 12, 0, "No Border").setShortcut('5', 'z');

  return true;
 }

 private int curveDrawable = 1;

 @Override
 public boolean onOptionsItemSelected(MenuItem item) {

  File myDir = new File(Environment.getExternalStorageDirectory(),
    "Drawings");
  myDir.mkdirs();
  Date now = new Date();
  String fname = "image" + now.getDate() + now.getSeconds() + ".jpg";
  File file = new File(myDir, fname);

  switch (item.getItemId()) {
  
  case 0:
   ((DrawingView) mView).colorChange();
   new ColorPicker(activity, this, "", Color.BLUE, Color.WHITE).show();
   return true;
   
  case 1:
   new ColorPicker(activity, this, "Bg Color", Color.BLUE, Color.WHITE).show();
   return true;
   
  case 2:
   if (mPaint.getMaskFilter() != mEmboss) {
    mPaint.setMaskFilter(mEmboss);
   } else {
    mPaint.setMaskFilter(null);
   }
   return true;
   
  case 3:
   if (mPaint.getMaskFilter() != mBlur) {
    mPaint.setMaskFilter(mBlur);
   } else {
    mPaint.setMaskFilter(null);
   }
   return true;
   
  case 4:
   ((DrawingView) mView).colorChange();
   mPaint = new Paint();
   mPaint.setDither(true);
   mPaint.setColor(bgcolor);
   mPaint.setStyle(Paint.Style.STROKE);
   mPaint.setStrokeJoin(Paint.Join.ROUND);
   mPaint.setStrokeCap(Paint.Cap.ROUND);
   mPaint.setStrokeWidth(13);
   return true;
   
  case 5:
   mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));
   mPaint.setAlpha(0x80);
   return true;
   
  case 6:
   ((DrawingView) mView).saveAsJpg(file, mView, true);
   return true;
   
  case 7:
   ((DrawingView) mView).saveAsJpg(file, mView, false);
   return true;
   
  case 8:
   ((DrawingView) mView).clearView();
   return true;
   
  case 10:
   isDrawBorder = true;
   colorChanged("Bg Color", bgcolor);
   curveDrawable = 1;
   return true;
   
  case 11:
   isDrawBorder = true;
   colorChanged("Bg Color", bgcolor);
   curveDrawable = 2;
   return true;
   
  case 12:
   isDrawBorder = true;
   colorChanged("Bg Color", bgcolor);
   curveDrawable = 0;
   return true;
   
  }
  return super.onOptionsItemSelected(item);
 }
}

PathWithPaint.java 
package com.example.draw;

import android.graphics.Paint;
import android.graphics.Path;

public class PathWithPaint {
 private Path path;

 public Path getPath() {
  return path;
 }

 public void setPath(Path path) {
  this.path = path;
 }
 
 private Paint mPaint;
 
 public Paint getmPaint() {
  return mPaint;
 }

 public void setmPaint(Paint mPaint) {
  this.mPaint = mPaint;
 } 
}


Sample screen shot of this application


Simple Drawing example in Android



Thank You


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