android 仿qq手写板涂鸦

来源：互联网发布：徐老师的淘宝店有哪些编辑：程序博客网时间：2024/05/04 05:04

以前博客的链接：点击打开链接

附上关键代码：

MainView.java

[java] view plaincopy

package com.tszy.views;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class MainView extends View {
private Paint paint;
private Canvas cacheCanvas;
private Bitmap cachebBitmap;
private Path path;
private int clr_bg, clr_fg;
public MainView(Context context, AttributeSet attrs) {
super(context, attrs);
clr_bg = Color.WHITE;
clr_fg = Color.CYAN;
paint = new Paint();
paint.setAntiAlias(true); // 抗锯齿
paint.setStrokeWidth(3); // 线条宽度
paint.setStyle(Paint.Style.STROKE); // 画轮廓
paint.setColor(clr_fg); // 颜色
path = new Path();
// 创建一张屏幕大小的位图，作为缓冲
cachebBitmap = Bitmap.createBitmap(480, 800, Config.ARGB_8888);
cacheCanvas = new Canvas(cachebBitmap);
cacheCanvas.drawColor(clr_bg);
}
public MainView(Context context) {
super(context);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(clr_bg);
// 绘制上一次的，否则不连贯
canvas.drawBitmap(cachebBitmap, 0, 0, null);
canvas.drawPath(path, paint);
}
/**
* 清空画布
*/
public void clear() {
path.reset();
cacheCanvas.drawColor(clr_bg);
invalidate();
}
/**
* 将画布的内容保存到文件
* @param filename
* @throws FileNotFoundException
*/
public void saveToFile(String filename) throws FileNotFoundException {
File f = new File(filename);
if(f.exists())
throw new RuntimeException("文件：" + filename + " 已存在！");
FileOutputStream fos = new FileOutputStream(new File(filename));
//将 bitmap 压缩成其他格式的图片数据
cachebBitmap.compress(CompressFormat.PNG, 50, fos);
try {
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private float cur_x, cur_y;
private boolean isMoving;
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN : {
cur_x = x;
cur_y = y;
path.moveTo(cur_x, cur_y);
isMoving = true;
break;
}
case MotionEvent.ACTION_MOVE : {
if (!isMoving)
break;
// 二次曲线方式绘制
path.quadTo(cur_x, cur_y, x, y);
// 下面这个方法貌似跟上面一样
// path.lineTo(x, y);
cur_x = x;
cur_y = y;
break;
}
case MotionEvent.ACTION_UP : {
// 鼠标弹起保存最后状态
cacheCanvas.drawPath(path, paint);
path.reset();
isMoving = false;
break;
}
}
// 通知刷新界面
invalidate();
return true;
}
}

Activity 代码：

[java] view plaincopy

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.iv_btn_clear :
view.clear();
break;
case R.id.iv_btn_save : {
try {
String sdState = Environment.getExternalStorageState(); // 判断sd卡是否存在
// 检查SD卡是否可用
if (!sdState.equals(android.os.Environment.MEDIA_MOUNTED)) {
Toast.makeText(this, "SD卡未准备好！", Toast.LENGTH_SHORT).show();
break;
}
//获取系统图片存储路径
File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
// Make sure the Pictures directory exists.
path.mkdirs();
//根据当前时间生成图片名称
Calendar c = Calendar.getInstance();
String name = ""
+ c.get(Calendar.YEAR) + c.get(Calendar.MONTH) + c.get(Calendar.DAY_OF_MONTH)
+ c.get(Calendar.HOUR_OF_DAY) + c.get(Calendar.MINUTE) + c.get(Calendar.SECOND)
+ ".png";
//合成完整路径，注意 / 分隔符
String string = path.getPath() + "/" + name;
view.saveToFile(string);
Toast.makeText(this, "保存成功！\n文件保存在：" + string, Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
Toast.makeText(this, "保存失败！\n" + e, Toast.LENGTH_LONG).show();
}
break;
}
}
}

没什么难度，主要是将Bitmap转PNG图片那里，找了一会发现 Canvas 没有直接或间接保存的方法，刚好这里我使用了双缓冲，另一块画布的内容位图自己创建的，很自然想到将这个画布的位图保存为文件即可。

再查看 Bitmap 有个 compress(CompressFormat format, int quality,OutputStream stream) 方法，很明显将文件输出流传给这个方法就OK

[java] view plaincopy

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.iv_btn_clear :
view.clear();
break;
case R.id.iv_btn_save : {
try {
String sdState = Environment.getExternalStorageState(); // 判断sd卡是否存在
// 检查SD卡是否可用
if (!sdState.equals(android.os.Environment.MEDIA_MOUNTED)) {
Toast.makeText(this, "SD卡未准备好！", Toast.LENGTH_SHORT).show();
break;
}
//获取系统图片存储路径
File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
// Make sure the Pictures directory exists.
path.mkdirs();
//根据当前时间生成图片名称
Calendar c = Calendar.getInstance();
String name = ""
+ c.get(Calendar.YEAR) + c.get(Calendar.MONTH) + c.get(Calendar.DAY_OF_MONTH)
+ c.get(Calendar.HOUR_OF_DAY) + c.get(Calendar.MINUTE) + c.get(Calendar.SECOND)
+ ".png";
//合成完整路径，注意 / 分隔符
String string = path.getPath() + "/" + name;
view.saveToFile(string);
Toast.makeText(this, "保存成功！\n文件保存在：" + string, Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
Toast.makeText(this, "保存失败！\n" + e, Toast.LENGTH_LONG).show();
}
break;
}
}
}