全体のキャンバスをアンドロイドキャンバスにjpegイメージとして保存するにはどうすればいいですか？

Question

私はキャンバスに何かを描いているので、この図面を私の記憶装置にJPEG画像として保存したい。私はそれに使用された方法に従って、私のディレクトリに画像sign.jpgを保存していますが、その空白の黒い画像はサイズ14.49kbで保存されていません。ここ

その

public Bitmap savebit(){ 

     Bitmap saveBitmap = Bitmap.createBitmap(this.getWidth(), this.getHeight(), Bitmap.Config.ARGB_8888); 
     Canvas canvas = new Canvas(saveBitmap); 
     canvas.setBitmap(saveBitmap); 
     this.draw(canvas); 

     File file = new File(Environment.getExternalStorageDirectory() + "/sign.jpg"); 

     try { 
      saveBitmap.compress(Bitmap.CompressFormat.JPEG, 100, new FileOutputStream(file)); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     return saveBitmap; 
    } 

Answer 1

ビューを使用すると、簡単にそのスクリーンショットを取ることができ、レイアウトにいくつかの場所を使用しているabcあなたのクラスを持っていることを確認してください。

Abc abc; 

Bitmap bmp = viewToBitmap(abc); 
Bitmap bmp = viewToBitmap(frameLayout); 
Bitmap bmp = viewToBitmap(LinearLayout); 
Bitmap bmp = viewToBitmap(AnyView); 

---

public Bitmap viewToBitmap(View view) { 
     Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888); 
     Canvas canvas = new Canvas(bitmap); 
     view.draw(canvas); 
     return bitmap; 
    } 

Answer 2

MyDrawView

import android.annotation.SuppressLint; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.Config; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.Path; 
import android.graphics.Rect; 
import android.util.AttributeSet; 
import android.util.LruCache; 
import android.view.MotionEvent; 
import android.view.View; 

public class MyDrawView extends View { 
    public Bitmap mBitmap; 
    public Canvas mCanvas; 
    private Path mPath; 
    private Paint mBitmapPaint; 
    private Paint mPaint; 


    public MyDrawView(Context c, AttributeSet attrs) { 
     super(c, attrs); 

     mPath = new Path(); 
     mBitmapPaint = new Paint(Paint.DITHER_FLAG); 

     mPaint = new Paint(); 
     mPaint.setAntiAlias(true); 
     mPaint.setDither(true); 
     mPaint.setColor(0xFF000000); 
     mPaint.setStyle(Paint.Style.STROKE); 
     mPaint.setStrokeJoin(Paint.Join.ROUND); 
     mPaint.setStrokeCap(Paint.Cap.ROUND); 
     mPaint.setStrokeWidth(9); 

    } 


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

    @Override 
    protected void onDraw(Canvas canvas) { 
     canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint); 

     canvas.drawPath(mPath, mPaint); 


    } 

    private float mX, mY; 
    private static final float TOUCH_TOLERANCE = 4; 

    private void touch_start(float x, float y) { 
     mPath.reset(); 
     mPath.moveTo(x, y); 
     mX = x; 
     mY = y; 
    } 
    private void touch_move(float x, float y) { 
     float dx = Math.abs(x - mX); 
     float dy = Math.abs(y - mY); 
     if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) { 
      mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2); 
      mX = x; 
      mY = y; 
     } 
    } 
    private void touch_up() { 
     mPath.lineTo(mX, mY); 
     // commit the path to our offscreen 
     mCanvas.drawPath(mPath, mPaint); 
     // kill this so we don't double draw 
     mPath.reset(); 
    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
     float x = event.getX(); 
     float y = event.getY(); 

     switch (event.getAction()) { 
      case MotionEvent.ACTION_DOWN: 
       touch_start(x, y); 
       invalidate(); 
       break; 
      case MotionEvent.ACTION_MOVE: 
       touch_move(x, y); 
       invalidate(); 
       break; 
      case MotionEvent.ACTION_UP: 
       touch_up(); 
       invalidate(); 
       break; 
     } 
     return true; 
    } 

    public Bitmap getBitmap() 
    { 
     //this.measure(100, 100); 
     //this.layout(0, 0, 100, 100); 
     this.setDrawingCacheEnabled(true); 
     this.buildDrawingCache(); 
     Bitmap bmp = Bitmap.createBitmap(this.getDrawingCache()); 
     this.setDrawingCacheEnabled(false); 


    return bmp; 
    } 



    public void clear(){ 
     mBitmap.eraseColor(Color.GREEN); 
     invalidate(); 
     System.gc(); 

    } 

} 

MainActivity

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 

import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.Config; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.Rect; 
import android.graphics.drawable.BitmapDrawable; 
import android.os.Bundle; 
import android.os.Environment; 
import android.view.Menu; 
import android.view.View; 
import android.view.View.MeasureSpec; 
import android.widget.Button; 
import android.widget.Toast; 


public class MainActivity extends Activity 
{ 
    MyDrawView myDrawView; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 

     super.onCreate(savedInstanceState); 
     // myDrawView = new MyDrawView(this, null); 
     setContentView(R.layout.activity_main); 
     myDrawView = (MyDrawView)findViewById(R.id.draw); 
     Button button1 = (Button)findViewById(R.id.button1);  
     button1.setOnClickListener(new View.OnClickListener() 
     { 
      public void onClick(View v) 
      {  


       File folder = new File(Environment.getExternalStorageDirectory().toString()); 
       boolean success = false; 
       if (!folder.exists()) 
       { 
        success = folder.mkdirs(); 
       } 

       System.out.println(success+"folder"); 

       File file = new File(Environment.getExternalStorageDirectory().toString() + "/sample.png"); 

      if (!file.exists()) 
      { 
        try { 
        success = file.createNewFile(); 
       } catch (IOException e) { 
        e.printStackTrace(); 
       } 
      } 

      System.out.println(success+"file"); 



      FileOutputStream ostream = null; 
       try 
       { 
       ostream = new FileOutputStream(file); 

       System.out.println(ostream); 
       View targetView = myDrawView; 

       // myDrawView.setDrawingCacheEnabled(true); 
       // Bitmap save = Bitmap.createBitmap(myDrawView.getDrawingCache()); 
       // myDrawView.setDrawingCacheEnabled(false); 
       // copy this bitmap otherwise distroying the cache will destroy 
       // the bitmap for the referencing drawable and you'll not 
       // get the captured view 
       // Bitmap save = b1.copy(Bitmap.Config.ARGB_8888, false); 
       //BitmapDrawable d = new BitmapDrawable(b); 
       //canvasView.setBackgroundDrawable(d); 
       // myDrawView.destroyDrawingCache(); 
       // Bitmap save = myDrawView.getBitmapFromMemCache("0"); 
       // myDrawView.setDrawingCacheEnabled(true); 
       //Bitmap save = myDrawView.getDrawingCache(false); 
       Bitmap well = myDrawView.getBitmap(); 
       Bitmap save = Bitmap.createBitmap(320, 480, Config.ARGB_8888); 
       Paint paint = new Paint(); 
       paint.setColor(Color.WHITE); 
       Canvas now = new Canvas(save); 
       now.drawRect(new Rect(0,0,320,480), paint); 
       now.drawBitmap(well, new Rect(0,0,well.getWidth(),well.getHeight()), new Rect(0,0,320,480), null); 

       // Canvas now = new Canvas(save); 
       //myDrawView.layout(0, 0, 100, 100); 
       //myDrawView.draw(now); 
       if(save == null) { 
        System.out.println("NULL bitmap save\n"); 
       } 
       save.compress(Bitmap.CompressFormat.PNG, 100, ostream); 
       //bitmap.compress(Bitmap.CompressFormat.PNG, 100, ostream); 
        //ostream.flush(); 
        //ostream.close(); 
       }catch (NullPointerException e) 
       { 
        e.printStackTrace(); 
        Toast.makeText(getApplicationContext(), "Null error", Toast.LENGTH_SHORT).show(); 
       } 

       catch (FileNotFoundException e) 
       { 
        e.printStackTrace(); 
        Toast.makeText(getApplicationContext(), "File error", Toast.LENGTH_SHORT).show(); 
       } 

       catch (IOException e) 
       { 
        e.printStackTrace(); 
        Toast.makeText(getApplicationContext(), "IO error", Toast.LENGTH_SHORT).show(); 
       } 

      } 
     }); 

    } 


    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.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" 
    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=".MainActivity" > 
<com.example.draw2.MyDrawView 
    android:id ="@+id/draw" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"></com.example.draw2.MyDrawView>" 
    <Button 
     android:id ="@+id/button1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="save" 
     android:layout_alignParentBottom="true" 
     ></Button>" 

</RelativeLayout> 

ための方法であります

とあなたのAndroidManifest.xmlには、あなたが

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.draw2" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="8" 
     android:targetSdkVersion="17" /> 
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/> 
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 

    <application 
     android:allowBackup="true" 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <activity 
      android:name="com.example.draw2.MainActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
    </application> 

</manifest>