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：
<"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。
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