Android学习笔记进阶之在图片上涂鸦(能清屏)

HandWritingActivity.java

[java]
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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(); } } }

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

[java]
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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); } }

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

[java]
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<?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>