[Java][Android]画板

代码

BasicCanvas.java

package com.Diamond.canvas;import android.view.SurfaceView;
import android.view.SurfaceHolder;
import android.graphics.Bitmap;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Color;public class BasicCanvas extends SurfaceView implements SurfaceHolder.Callback {public class DrawThread extends Thread {&＃64;Overridepublic void run() {while(true) {int bw &＃61; bitmap.getWidth();int bh &＃61; bitmap.getHeight();Canvas canvas &＃61; getCanvas();canvas.drawARGB(255,0,0,0);canvas.drawBitmap(bitmap,new Rect(0,0,bw,bh),new Rect(0,0,bw,bh),null);update(canvas);}}}public Bitmap bitmap;public DrawThread thread;public SurfaceHolder holder;public BasicCanvas(Context context) {super(context);holder &＃61; getHolder();holder.addCallback(this);}public Canvas getCanvas() {return holder.lockCanvas();}public BasicCanvas update(Canvas canvas) {holder.unlockCanvasAndPost(canvas);return this;}public BasicCanvas createNew(int width,int height) {bitmap &＃61; Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);return this;}public BasicCanvas clear(int color) {getPaintableCanvas().drawColor(color);return this;}public Canvas getPaintableCanvas() {return new Canvas(bitmap);}&＃64;Overridepublic void surfaceCreated(SurfaceHolder p1) {bitmap &＃61; Bitmap.createBitmap(getWidth(),getHeight(),Bitmap.Config.ARGB_8888);thread &＃61; new DrawThread();thread.start();}&＃64;Overridepublic void surfaceChanged(SurfaceHolder p1, int p2, int p3, int p4) {}&＃64;Overridepublic void surfaceDestroyed(SurfaceHolder p1) {}
}


用法

这是一个非常简单的类&＃xff0c;把画图线程放了进去&＃xff0c;只要调用getPaintableCanvas()就能获得一个Canvas对象&＃xff0c;然后进行画图操作&＃xff0c;最后什么都不用干&＃xff0c;线程会自动把图画出来

提示

我继承BasicCanvas的时候出了问题&＃xff0c;明明直接用BasicCanvas还是正常的