这是我的类，我实现了在画布上绘制的线程。
package com.example.drawing;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector.OnDoubleTapListener;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import com.example.drawing.DrawingActivity;
public class DrawingSurface extends SurfaceView implements SurfaceHolder.Callback {
public static Boolean _run;
public static DrawThread thread;
public Canvas canvas = null;
private CommandManager commandManager;
//private Bitmap myBitmap;
private Bitmap mBitmap;
public DrawingSurface(Context context, AttributeSet attrs) {
super(context, attrs);
getHolder().addCallback(this);
commandManager = new CommandManager();
thread = new DrawThread(getHolder());
}
class DrawThread extends Thread{
private SurfaceHolder mSurfaceHolder;
public DrawThread(SurfaceHolder surfaceHolder){
mSurfaceHolder = surfaceHolder;
}
public void setRunning(boolean run) {
_run = run;
}
@Override
public void run() {
//Canvas canvas = null;
while (_run){
try{
canvas = mSurfaceHolder.lockCanvas(null);
if(mBitmap == null){
mBitmap = Bitmap.createBitmap (1, 1, Bitmap.Config.ARGB_8888);
}
final Canvas c = new Canvas (mBitmap);
//canvas.drawColor(0, PorterDuff.Mode.CLEAR);
c.drawColor(0, PorterDuff.Mode.CLEAR);
canvas.drawColor(Color.WHITE);
// Bitmap kangoo = BitmapFactory.decodeResource(getResources(),R.drawable.icon);
// canvas.drawBitmap (kangoo, 0, 200,null);
// works for logo
// Bitmap kangoo = BitmapFactory.decodeResource(getResources(),R.drawable.icon);
// c.drawBitmap (kangoo, 0, 200,null);
if(!(DrawingActivity.imagePath==null)){
c.drawBitmap(DrawingActivity.mBitmap, 0, 0, null);
}
commandManager.executeAll(c);
canvas.drawBitmap (mBitmap, 0, 0,null);
} finally {
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
public void addDrawingPath (DrawingPath drawingPath){
commandManager.addCommand(drawingPath);
}
public boolean hasMoreRedo(){
return commandManager.hasMoreRedo();
}
public void redo(){
commandManager.redo();
}
public void undo(){
commandManager.undo();
}
public boolean hasMoreUndo(){
return commandManager.hasMoreRedo();
}
public Bitmap getBitmap(){
Bitmap kangoo = BitmapFactory.decodeResource(getResources(),R.drawable.resize_drawing_logo);
Bitmap myBitmap = addLogo(mBitmap, kangoo);
return myBitmap;
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// TODO Auto-generated method stub
mBitmap = Bitmap.createBitmap (width, height, Bitmap.Config.ARGB_8888);;
}
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
//thread.setRunning(true); // Edited By Shreyash
_run=true; //
thread.start();
// error at this line
// if(!thread.isAlive())
// thread.start();
}
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
boolean retry = true;
//thread.setRunning(false); //Edited By Shreyash
_run = false;
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
// we will try it again and again...
}
}
}
public static Bitmap addLogo(Bitmap mainImage, Bitmap logoImage) { // can add a 3rd parameter 'String loc' if you want to save the new image - left some code to do that at the bottom
Bitmap finalImage = null;
int width, height = 0;
width = mainImage.getWidth();
height = mainImage.getHeight();
finalImage = Bitmap.createBitmap(width, height, mainImage.getConfig());
Canvas canvas = new Canvas(finalImage);
canvas.drawBitmap(mainImage, 0,0,null);
canvas.drawBitmap(logoImage, canvas.getWidth()-logoImage.getWidth() ,canvas.getHeight()-logoImage.getHeight() ,null);
return finalImage;
}
}
我正在为另一个活动创建此类的Object并进行绘制。 现在，当我要进行另一项活动，然后回到此活动时，就会发生错误。
错误日志：
11-15 11:26:40.738: ERROR/AndroidRuntime(668): FATAL EXCEPTION: main
11-15 11:26:40.738: ERROR/AndroidRuntime(668): java.lang.IllegalThreadStateException: Thread already started.
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at java.lang.Thread.start(Thread.java:1322)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at com.example.drawing.DrawingSurface.surfaceCreated(DrawingSurface.java:119)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.SurfaceView.updateWindow(SurfaceView.java:532)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:206)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.View.dispatchWindowVisibilityChanged(View.java:3891)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:719)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewRoot.performTraversals(ViewRoot.java:744)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.os.Handler.dispatchMessage(Handler.java:99)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.os.Looper.loop(Looper.java:123)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at android.app.ActivityThread.main(ActivityThread.java:4627)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at java.lang.reflect.Method.invokeNative(Native Method)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at java.lang.reflect.Method.invoke(Method.java:521)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-15 11:26:40.738: ERROR/AndroidRuntime(668): at dalvik.system.NativeStart.main(Native Method)
11-15 11:26:40.768: WARN/ActivityManager(60): Force finishing activity com.example.drawing/.DrawingActivity
11-15 11:26:41.338: WARN/ActivityManager(60): Activity pause timeout for HistoryRecord{450073d0 com.example.drawing/.DrawingActivity}
我不知道为什么我会收到此错误。 所以请帮我处理这个帖子。 感谢。
答案 0 :(得分：2)
嗯，就像它说的那样：你在已经启动的线程上调用start()。想要在一段代码中创建一个线程，然后在另一段代码中启动它，非常不寻常......如果你能把两者放在一起，就不会发生这个问题。
（顺便说一句，看起来你的线程基本上是紧密循环的，这对我来说似乎不是一个好主意，但这是另一回事。）
答案 1 :(得分：1)
在我的情况下，我通过初始化新线程来修复它：
public void surfaceCreated(SurfaceHolder holder) {
gameThread = new MyThread(getHolder(), _context, this);
gameThread.setRunning(true);
gameThread.start();
}
答案 2 :(得分：0)
修改surfaceDestroyed（）方法：
thread.interrupt();
thread.join();
你需要包围代码
thread.start();
。 Interrupt（）方法抛出中断异常
对我来说效果很好。