本文实例讲述了Android编程实现在Bitmap上涂鸦效果。分享给大家供大家参考，具体如下：

布局文件：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:orientation="vertical" > 
 <LinearLayout 
  android:id="@+id/handwriteview" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" /> 
 <LinearLayout 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" 
  android:orientation="horizontal" 
  android:gravity="center_horizontal" > 
  <Button 
   android:id="@+id/clear" 
   android:layout_width="200dp" 
   android:layout_height="wrap_content" 
   android:text="清屏" /> 
 </LinearLayout> 
</LinearLayout> 

重写的View文件：

public class HandWrite extends View 
{ 
 private Paint paint = null; 
 private Bitmap originalBitmap = null; 
 private Bitmap new1Bitmap = null; 
 private Bitmap new2Bitmap = null; 
 private float clickX = 0,clickY = 0; 
 private float startX = 0,startY = 0; 
 private boolean isMove = true; 
 private boolean isClear = false; 
 private int color = Color.GREEN; 
 private float strokeWidth = 2.0f; 
 public HandWrite(Context context,Bitmap b) 
 { 
  super(context); 
  originalBitmap = Bitmap.createBitmap(b).copy(Bitmap.Config.ARGB_8888, true); 
  new1Bitmap = Bitmap.createBitmap(originalBitmap); 
 } 
 public void clear(){ 
  isClear = true; 
  new2Bitmap = Bitmap.createBitmap(originalBitmap); 
  invalidate(); 
 } 
 public void setstyle(float strokeWidth){ 
  this.strokeWidth = strokeWidth; 
 } 
 @Override 
 protected void onDraw(Canvas canvas) 
 { 
  super.onDraw(canvas); 
  canvas.drawBitmap(HandWriting(new1Bitmap), 0, 0,null); 
 } 
 public Bitmap HandWriting(Bitmap originalBitmap) 
 { 
  Canvas canvas = null; 
  if(isClear){ 
   canvas = new Canvas(new2Bitmap); 
  } 
  else{ 
   canvas = new Canvas(originalBitmap); 
  } 
  paint = new Paint(); 
  paint.setStyle(Style.STROKE); 
  paint.setAntiAlias(true); 
  paint.setColor(color); 
  paint.setStrokeWidth(strokeWidth); 
  if(isMove){ 
   canvas.drawLine(startX, startY, clickX, clickY, paint); 
  } 
  startX = clickX; 
  startY = clickY; 
  if(isClear){ 
   return new2Bitmap; 
  } 
  return originalBitmap; 
 } 
 @Override 
 public boolean onTouchEvent(MotionEvent event) 
 { 
  clickX = event.getX(); 
  clickY = event.getY(); 
  if(event.getAction() == MotionEvent.ACTION_DOWN){ 
   isMove = false; 
   invalidate(); 
   return true; 
  } 
  else if(event.getAction() == MotionEvent.ACTION_MOVE){ 
   isMove = true; 
   invalidate(); 
   return true; 
  } 
  return super.onTouchEvent(event); 
 } 
} 

Activity文件：

public class HandWritingActivity extends Activity 
{ 
 /** Called when the activity is first created. */ 
 private LinearLayout handWrite = null; 
 private Button clear = null; 
 int requestWidth=116;
 int requestHeight=173;
 int inSampleSize;
 @Override 
 public void onCreate(Bundle savedInstanceState) 
 { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_hand_writing); 
  handWrite = (LinearLayout)findViewById(R.id.handwriteview); 
  clear = (Button)findViewById(R.id.clear); 
  clear.setOnClickListener(new clearListener()); 
 } 
 private class clearListener implements OnClickListener{ 
  public void onClick(View v) 
  { 
//   handWrite.clear(); 
   BitmapFactory.Options opts = new Options();
   opts.inJustDecodeBounds = true;// 让 bimapfactory假的解析这个位图,只获取位图的边框信息
   BitmapFactory.decodeResource(getResources(), R.drawable.cool, opts);
   if (opts.outHeight > requestHeight || opts.outWidth > requestWidth) {
    if (opts.outWidth > opts.outHeight) {
     inSampleSize = Math.round((float) opts.outHeight
       / (float) requestHeight);
    } else {
     inSampleSize = Math.round((float) opts.outWidth
       / (float) requestWidth);
    }
   }
    System.out.println("宽度：" + opts.outWidth);
    System.out.println("高度：" + opts.outHeight);
   opts.inSampleSize = inSampleSize;
   System.out.println(inSampleSize);
   opts.inJustDecodeBounds = false;// 由于已经得到了缩放比例 ,让位图工厂真正的解析这个位图
   // 由于前面 我们已经解析了这个输入流, 需要重新初始化这个输入流
   Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.cool, opts);
   HandWrite hw = new HandWrite(HandWritingActivity.this, b);
   System.out.println(b.getWidth());
   handWrite.addView(hw);
  } 
 } 
} 

整合的一个涂鸦工具类：

/**
 * 使用方法：
 * 1. 创建TuYaView类实例
 * 2. 调用drawTuya方法
 * 3. 参数1：context
 * 4. 参数2：图像的byte[]字节数组
 * 5. ImageView实例
 * 6. 画笔定义
 * **/
import com.ziipin.lhdc.utils.ToastUtil;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.BitmapFactory.Options;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
public class TuYaView {
 // 原始图片
 private Bitmap mOrignBitmap;
 private Bitmap mEditBitmap;
 private int inSampleSize;
 private int requestWidth = 500;
 private int requestHeight = 700;
 /** 编辑图片的画布 */
 private Canvas mCanvas;
 private ImageView image;
 private Paint mPaint;
 public Bitmap drawTuya(Context context, byte[] _data, ImageView image,
   Paint mPaint) {
  this.image = image;
  this.mPaint = mPaint;
  mOrignBitmap = BitmapFactory.decodeByteArray(_data, 0, _data.length);
  return showEditBitmap(context, _data, image);
 }
 /**
  * 显示编辑的图片
  */
 private Bitmap showEditBitmap(Context context, byte[] _data, ImageView image) {
  mOrignBitmap = getScaleBitmap(_data, image);
  if (mOrignBitmap == null) {
   ToastUtil.show(context, "编辑出错");
  }
  mEditBitmap = mOrignBitmap.copy(mOrignBitmap.getConfig(), true);
  mCanvas = new Canvas(mEditBitmap);
  mCanvas.drawBitmap(mOrignBitmap, new Matrix(), new Paint());
  image.setImageBitmap(mEditBitmap);
  image.setOnTouchListener(mTouchListener);
  return mEditBitmap;
 }
 /**
  * 获取结果缩放放后的图片
  * 
  * @return
  */
 private Bitmap getScaleBitmap(byte[] _data, ImageView image) {
  BitmapFactory.Options opts = new Options();
  opts.inJustDecodeBounds = true;// 让 bimapfactory假的解析这个位图,只获取位图的边框信息
  BitmapFactory.decodeByteArray(_data, 0, _data.length, opts);
  if (opts.outHeight > requestHeight || opts.outWidth > requestWidth) {
   if (opts.outWidth > opts.outHeight) {
    inSampleSize = Math.round((float) opts.outHeight
      / (float) requestHeight);
   } else {
    inSampleSize = Math.round((float) opts.outWidth
      / (float) requestWidth);
   }
  }
  opts.inSampleSize = inSampleSize;
  opts.inJustDecodeBounds = false;// 由于已经得到了缩放比例 ,让位图工厂真正的解析这个位图
  // 由于前面 我们已经解析了这个输入流, 需要重新初始化这个输入流
  Bitmap bmp = BitmapFactory
    .decodeByteArray(_data, 0, _data.length, opts);
  return bmp;
 }
 // touch事件
 private OnTouchListener mTouchListener = new OnTouchListener() {
  int startx = 0;
  int starty = 0;
  @Override
  public boolean onTouch(View v, MotionEvent event) {
   switch (event.getAction()) {
   case MotionEvent.ACTION_DOWN:// 手指第一次触摸屏幕
    startx = (int) event.getX();
    starty = (int) event.getY();
    break;
   case MotionEvent.ACTION_MOVE: // 手指在imageview上中移动
    int x = (int) event.getX();
    int y = (int) event.getY();
    mCanvas.drawLine(startx, starty, x, y, mPaint);
    startx = (int) event.getX();
    starty = (int) event.getY();
    image.invalidate();
    break;
   }
   return true;
  }
 };
}

希望本文所述对大家Android程序设计有所帮助。