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HandWritingActivity.java

package xiaosi.handWriting;import android.app.Activity;import android.app.AlertDialog;import android.content.DialogInterface;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class HandWritingActivity extends Activity{ /** Called when the activity is first created. */ private HandWrite handWrite = null; private Button clear = null; @Override public void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.main);    handWrite = (HandWrite)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();  } }}

HandWrite.java

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, AttributeSet attrs) {  super(context, attrs);  originalBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.girl_a);  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); }   }

main.xml

<?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" >    <xiaosi.handWriting.HandWrite        android:id="@+id/handwriteview"        android:layout_width="fill_parent"        android:layout_height="380dp" />    <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>