Android 实现手写板技术

一箫一剑平生意，负尽狂名十五年。这篇文章主要讲述Android 实现手写板技术相关的知识，希望能为你提供帮助。
android手写板和涂鸦的功能，代码如下：

< 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(); } } } }

【Android 实现手写板技术】

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(); } }); } }