Question

为什么我在此代码中出现对象分辨率错误？关于'displayObject.ob1'的for循环中发生错误：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    setVolumeControlStream(AudioManager.STREAM_MUSIC);
    Button button1=(Button)findViewById(R.id.button1);
    Button button2=(Button)findViewById(R.id.button2);
    button1.setOnClickListener(this);
    button2.setOnClickListener(this);
}

public void onClick(View v) {
    int resId;
    switch (v.getId()) {
    case R.id.button1:
        resId = R.raw.a;
        break;
    case R.id.button2:
        resId = R.raw.b;
        break;
    default:
        resId = R.raw.a;
        break;
    }
    // Release any resources from previous MediaPlayer
    if (mp != null) {
        mp.release();
    }

    mp = MediaPlayer.create(this, resId);
    mp.start();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
protected void onDestroy() {
    if(null!=mp){
        mp.release();
    }
    super.onDestroy();
}

此对象在此处实例化：

import java.awt.*;
import javax.swing.*;

public class drawr extends JPanel{

    public static int animationSpeed=470;
    public static int diameter = 50;

    public void paintComponent(Graphics g){

        super.paintComponent(g);
        g.setColor(Color.decode("#ffc000"));
        g.drawLine(0, 0, getWidth(), getHeight());
        for(int cnt=0; cnt/2<=displayObject.ob1.noOfVerts; cnt+=2){
            g.drawLine(displayObject.ob1.coord[cnt], displayObject.ob1.coord[cnt+1], ob1.coord[cnt+2], ob1.coord[cnt+3]);
        }
}

并在此构建：

import java.awt.Color;
import javax.swing.*;

public class MainClass{

    public static final int windowWidth = 1280;
    public static final int windowHeight = 640;
    public static boolean crash = false;

    public static displayObject ob1, ob2, ob3;

    public static void main(String[] args)
        throws InterruptedException {

        String colorString="#ff0000";
        int ob1verts[]={10,10,50,50,30,80};
        displayObject ob1=new displayObject("#ff0000", ob1verts);
    }
}

Answer 1

除了你的代码乱七八糟的事实，这一行

displayObject ob1 = new displayObject("#ff0000", ob1verts);

应该只是：

ob1 = new displayObject("#ff0000", ob1verts);

您已声明ob1，ob2＆amp;代码中的ob3，即

public static displayObject ob1, ob2, ob3; // ob1 declared

至于您的错误， ob1 是displayObject类的静态变量，
并且您无法使用displayObject.ob1访问它您需要将 ob1 的引用从MainClass传递给drawr。
或者你可能意味着MainClass.ob1？因为它在MainClass中声明为静态变量。

Java对象引用

1 个答案: