implement the sharing functionality

app/src/main/java/com/simplemobiletools/draw/MainActivity.java

@@ -1,18 +1,31 @@
 package com.simplemobiletools.draw;
 
+import android.content.Intent;
+import android.graphics.Bitmap;
 import android.graphics.Color;
+import android.net.Uri;
 import android.os.Bundle;
+import android.support.v4.content.FileProvider;
 import android.support.v7.app.AppCompatActivity;
+import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
 import butterknife.Bind;
 import butterknife.ButterKnife;
 import butterknife.OnClick;
 import yuku.ambilwarna.AmbilWarnaDialog;
 
 public class MainActivity extends AppCompatActivity {
+    private static final String TAG = MainActivity.class.getSimpleName();
+    private static final String FOLDER_NAME = "images";
+    private static final String FILE_NAME = "simple-draw.png";
     @Bind(R.id.my_canvas) MyCanvas myCanvas;
     @Bind(R.id.color_picker) View colorPicker;
     private int color;
@@ -44,7 +57,48 @@ public class MainActivity extends AppCompatActivity {
     }
 
     private void shareImage() {
+        final String shareTitle = getResources().getString(R.string.share_via);
+        final Bitmap bitmap = myCanvas.getBitmap();
+        final Intent sendIntent = new Intent();
+        final Uri uri = getImageUri(bitmap);
+        if (uri == null)
+            return;
 
+        sendIntent.setAction(Intent.ACTION_SEND);
+        sendIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+        sendIntent.setDataAndType(uri, getContentResolver().getType(uri));
+        sendIntent.putExtra(Intent.EXTRA_STREAM, uri);
+        sendIntent.setType("image/*");
+        startActivity(Intent.createChooser(sendIntent, shareTitle));
+    }
+
+    private Uri getImageUri(Bitmap bitmap) {
+        final ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+        bitmap.compress(Bitmap.CompressFormat.PNG, 0, bytes);
+
+        final File folder = new File(getCacheDir(), FOLDER_NAME);
+        if (!folder.exists()) {
+            if (!folder.mkdir())
+                return null;
+        }
+
+        final File file = new File(folder, FILE_NAME);
+        FileOutputStream fileOutputStream = null;
+        try {
+            fileOutputStream = new FileOutputStream(file);
+            fileOutputStream.write(bytes.toByteArray());
+        } catch (Exception e) {
+            Log.e(TAG, "getImageUri 1 " + e.getMessage());
+        } finally {
+            try {
+                if (fileOutputStream != null)
+                    fileOutputStream.close();
+            } catch (IOException e) {
+                Log.e(TAG, "getImageUri 2 " + e.getMessage());
+            }
+        }
+
+        return FileProvider.getUriForFile(this, "com.simplemobiletools.draw.fileprovider", file);
     }
 
     @OnClick(R.id.undo)

app/src/main/java/com/simplemobiletools/draw/MyCanvas.java

@@ -1,6 +1,7 @@
 package com.simplemobiletools.draw;
 
 import android.content.Context;
+import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
@@ -55,6 +56,14 @@ public class MyCanvas extends View {
         color = newColor;
     }
 
+    public Bitmap getBitmap() {
+        final Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
+        final Canvas canvas = new Canvas(bitmap);
+        canvas.drawColor(Color.WHITE);
+        draw(canvas);
+        return bitmap;
+    }
+
     @Override
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);