<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  xmlns:greendroid="http://schemas.android.com/apk/res/com.cyrilmottier.android.gdcatalog"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  android:orientation="vertical" >  <FrameLayout  android:id="@+id/tablet_view"  android:layout_width="fill_parent"  android:layout_height="300dp" >  </FrameLayout>  <LinearLayout  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:background="@android:drawable/bottom_bar"  android:paddingTop="4dp" >  <Button  android:id="@+id/write_pad_ok"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="确定" />  <Button  android:id="@+id/write_pad_clear"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="清除" />  <Button  android:id="@+id/write_pad_cancel"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:layout_weight="1"  android:text="取消" />  </LinearLayout>  </LinearLayout>  

public class MainActivity extends Activity {  private ImageView mIVSign;  private TextView mTVSign;  private Bitmap mSignBitmap;  /** Called when the activity is first created. */  @Override  public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  mIVSign = (ImageView) findViewById(R.id.iv_sign);  mTVSign = (TextView) findViewById(R.id.tv_sign);  mTVSign.setOnClickListener(new OnClickListener() {  @Override  public void onClick(View view) {  WritePadDialog mWritePadDialog = new WritePadDialog(  MainActivity.this, new WriteDialogListener() {  @Override  public void onPaintDone(Object object) {  mSignBitmap = (Bitmap) object;  createSignFile();  mIVSign.setImageBitmap(mSignBitmap);  mTVSign.setVisibility(View.GONE);  }  });  mWritePadDialog.show();  }  });  }  //创建签名文件  private void createSignFile() {  ByteArrayOutputStream baos = null;  FileOutputStream fos = null;  String path = null;    File file = null;  try {    path = Environment.getExternalStorageDirectory() + File.separator + System.currentTimeMillis() + ".jpg";   file = new File(path);  fos = new FileOutputStream(file);  baos = new ByteArrayOutputStream();  //如果设置成Bitmap.compress(CompressFormat.JPEG, 100, fos) 图片的背景都是黑色的  mSignBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);    byte[] b = baos.toByteArray();    if (b != null) {    fos.write(b);   }    } catch (IOException e) {    e.printStackTrace();    } finally {    try {    if (fos != null) {  fos.close();  }  if (baos != null) {  baos.close();  }  } catch (IOException e) {    e.printStackTrace();    }    }    }
}  

public class PaintView extends View {  private Paint mPaint;  private Path mPath;  private Bitmap mBitmap;  private Canvas mCanvas;  private int screenWidth, screenHeight;  private float currentX, currentY;  public PaintView(Context context, int screenWidth, int screenHeight) {  super(context);  this.screenWidth = screenWidth;  this.screenHeight = screenHeight;  init();  }  private void init() {  mPaint = new Paint();  mPaint.setAntiAlias(true); // 去除锯齿  mPaint.setStrokeWidth(5);  mPaint.setStyle(Paint.Style.STROKE);  mPaint.setColor(Color.BLACK);  mPath = new Path();  mBitmap = Bitmap.createBitmap(screenWidth, screenHeight, Config.ARGB_8888);  mCanvas = new Canvas(mBitmap);
//      mCanvas.drawColor(Color.WHITE);
    }  @Override  protected void onDraw(Canvas canvas) {  canvas.drawBitmap(mBitmap, 0, 0, null);  canvas.drawPath(mPath, mPaint);  }  @Override  public boolean onTouchEvent(MotionEvent event) {  float x = event.getX();  float y = event.getY();  switch (event.getAction()) {  case MotionEvent.ACTION_DOWN:  currentX = x;  currentY = y;  mPath.moveTo(currentX, currentY);  break;  case MotionEvent.ACTION_MOVE:  currentX = x;  currentY = y;  mPath.quadTo(currentX, currentY, x, y); // 画线  break;  case MotionEvent.ACTION_UP:  mCanvas.drawPath(mPath, mPaint);  break;  }  invalidate();  return true;  }  public Bitmap getPaintBitmap() {  return resizeImage(mBitmap, 320, 480);  }  public Path getPath() {  return mPath;  }  // 缩放  public static Bitmap resizeImage(Bitmap bitmap, int width, int height) {  int originWidth = bitmap.getWidth();  int originHeight = bitmap.getHeight();  float scaleWidth = ((float) width) / originWidth;  float scaleHeight = ((float) height) / originHeight;  Matrix matrix = new Matrix();  matrix.postScale(scaleWidth, scaleHeight);  Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, originWidth,  originHeight, matrix, true);  return resizedBitmap;  }  //清除画板  public void clear() {  if (mCanvas != null) {  mPath.reset();  mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);  invalidate();  }  }
}  

public class WritePadDialog extends Dialog {  private Context mContext;  private WriteDialogListener mWriteDialogListener;  private PaintView mPaintView;  private FrameLayout mFrameLayout;  private Button mBtnOK, mBtnClear, mBtnCancel;  public WritePadDialog(Context context,  WriteDialogListener writeDialogListener) {  super(context);  this.mContext = context;  this.mWriteDialogListener = writeDialogListener;  }  @Override  protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  requestWindowFeature(Window.FEATURE_NO_TITLE); //无标题
        setContentView(R.layout.write_pad);  mFrameLayout = (FrameLayout) findViewById(R.id.tablet_view);  // 获取屏幕尺寸  DisplayMetrics mDisplayMetrics = new DisplayMetrics();  getWindow().getWindowManager().getDefaultDisplay().getMetrics(mDisplayMetrics);  int screenWidth = mDisplayMetrics.widthPixels;  int screenHeight = mDisplayMetrics.heightPixels;  mPaintView = new PaintView(mContext, screenWidth, screenHeight);  mFrameLayout.addView(mPaintView);  mPaintView.requestFocus();  mBtnOK = (Button) findViewById(R.id.write_pad_ok);  mBtnOK.setOnClickListener(new View.OnClickListener() {  @Override  public void onClick(View v) {  if (mPaintView.getPath().isEmpty()) {  Toast.makeText(mContext, "请写下你的大名", Toast.LENGTH_SHORT).show();  return;  }  mWriteDialogListener.onPaintDone(mPaintView.getPaintBitmap());  dismiss();  }  });  mBtnClear = (Button) findViewById(R.id.write_pad_clear);  mBtnClear.setOnClickListener(new View.OnClickListener() {  @Override  public void onClick(View v) {  mPaintView.clear();  }  });  mBtnCancel = (Button) findViewById(R.id.write_pad_cancel);  mBtnCancel.setOnClickListener(new View.OnClickListener() {  @Override  public void onClick(View v) {  cancel();  }  });  }
}  

/** * 监听手写板对话框* @author chengcj1 *  */
public interface WriteDialogListener {  public void onPaintDone(Object object);
}