Question

我有一个名为OurView的班级。我有3 Buttons来调用moveImage()并将其传递给两个数字，具体取决于Button。moveImage()。

xCoord应该会更改yCoord和xCoord的值，而这似乎也是如此。从yCoord打印moveImage()和delay()时，它们会显示正确的值。

但是，从doDraw()或package com.thatoneprogrammerkid.gameminimum; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.os.Handler; import android.util.AttributeSet; import android.view.SurfaceHolder; import android.view.SurfaceView; public class OurView extends SurfaceView implements SurfaceHolder.Callback { private SurfaceHolder holder; private Handler handler = new Handler(); private Bitmap testimg; private int xCoord = 500; private int yCoord = 500; int xPos; int yPos; public OurView(Context context) { super(context); init(); } public OurView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public OurView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init() { holder = getHolder(); holder.addCallback(this); testimg = BitmapFactory.decodeResource(getResources(),R.drawable.testimg); } void moveImage(int xChange, int yChange) { this.xCoord = this.xCoord + xChange; this.yCoord = this.yCoord + yChange; System.out.println("Move Image"); printCoords(); } void printCoords() { System.out.println(xCoord); System.out.println(yCoord); } void delay() { System.out.println("Delay"); printCoords(); handler.postDelayed(new Runnable() { public void run() { Canvas canvas = getHolder().lockCanvas(); System.out.println("Run"); printCoords(); if(canvas != null){ synchronized (getHolder()) { doDraw(canvas, xCoord, yCoord); } holder.unlockCanvasAndPost(canvas); } } }, 33); } void doDraw(Canvas canvas, int x, int y) { xPos = this.xCoord + (testimg.getWidth()/2); yPos = this.yCoord + (testimg.getHeight()/2); System.out.println("Draw"); printCoords(); canvas.drawARGB(255, 55, 255, 255); canvas.drawBitmap(testimg, x, y, null); delay(); } @Override public void surfaceCreated(final SurfaceHolder holder) { delay(); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {} @Override public void surfaceDestroyed(SurfaceHolder holder) {} }打印时，它们会显示原始值500.

我做错了什么导致变量没有更新？

以下是OurView类：

package com.thatoneprogrammerkid.gameminimum;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.os.Bundle;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;

public class SurfaceViewExample extends Activity {

    OurView gameView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        gameView = new OurView(this);
        setContentView(R.layout.activity_surface_view_example);
    }

    public void arrowPressed(View view) {
        switch (view.getId()) {

            case R.id.arrowLeft:
                gameView.moveImage(-1,0);
                break;

            case R.id.arrowRight:
                gameView.moveImage(1,0);
                break;

            case R.id.arrowUp:
                gameView.moveImage(0,1);
                break;
        }
    }
}

这是按钮按下的句柄：

510
500

编辑：

澄清一下，按下按钮10次后，moveImage（）中的printCoords（）会显示以下内容：

500
500

并且所有其他位置的printCoords（）显示以下内容：

Test.php

Answer 1

如果我猜对了，你用来调用moveImage（）和delay（）的引用是不一样的。也许你做了类似的事情：

ourView = new OurView();

调用moveImage后。

类变量在不同方法中具有不同的值

1 个答案: