Android编程实现的手写板和涂鸦功能,android编程
本文实例讲述了android编程实现的手写板和涂鸦功能。分享给大家供大家参考，具体如下：
下面仿一个android手写板和涂鸦的功能，直接上代码：
write_pad.xml
[Java] 查看源文件 复制代码
<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>
这个是手写板的主要布局文件，能够手写的部分是一个framelayout。下面有确定、清除和取消按钮，用来保存和擦除签名。
主要代码逻辑如下：
mainactivity.java
[Java] 查看源文件 复制代码
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();
}
}
}
}
paintview.java
[Java] 查看源文件 复制代码
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();
}
}
}
writepaddialog.java
[Java] 查看源文件 复制代码
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();
}
});
}
}
writediloglistener.java
[Java] 查看源文件 复制代码
package com.jackie.handwriting;
/**
* 监听手写板对话框
* @author chengcj1
*
*/
public interface writedialoglistener {
public void onpaintdone(object object);
}
效果如下：
更多关于android相关内容感兴趣的读者可查看本站专题：《android图形与图像处理技巧总结》、《android开发入门与进阶教程》、《android调试技巧与常见问题解决方法汇总》、《android基本组件用法总结》、《android视图view技巧总结》、《android布局layout技巧总结》及《android控件用法总结》
文章来源：安卓巴士
