Android编程实现的手写板和涂鸦功能

<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>

package com.jackie.handwriting;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import android.app.Activity;import android.graphics.Bitmap;import android.os.Bundle;import android.os.Environment;import android.view.View;import android.view.View.OnClickListener;import android.widget.ImageView;import android.widget.TextView;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();      }    }  }}

package com.jackie.handwriting;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.Path;import android.graphics.PorterDuff;import android.view.MotionEvent;import android.view.View;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();    }  }}

package com.jackie.handwriting;import android.app.Dialog;import android.content.Context;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.View;import android.view.Window;import android.widget.Button;import android.widget.FrameLayout;import android.widget.Toast;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();      }    });  }}

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