总是显示R.id.main cannot be resolved

Question

这是代码。。

package p.progress;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.R;
public class ProgressbarActivity extends Activity {
/** Called when the activity is first created. */

private ProgressBar firstBar =null;
private ProgressBar secondBar =null;
private Button myButton =null;
private int i =0 ;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
firstBar = (ProgressBar)findViewById(R.id.firstBar);
secondBar =(ProgressBar)findViewById(R.id.secondBar);
myButton =(Button)findViewById(R.id.myButton);
myButton.setOnClickListener(new ButtonListener());
System.out.println(firstBar.getMax());
}
class ButtonListener implements OnClickListener{
public void onClick(View v){
if(i == 0){
firstBar.setVisibility(View.VISIBLE);
secondBar.setVisibility(View.VISIBLE);
}
else if (i<100)
{
firstBar.setProgress(i);
firstBar.setSecondaryProgress(i + 10);
secondBar.setProgress(i);
}
else{
firstBar.setVisibility(View.GONE);
secondBar.setVisibility(View.GONE);
}
i = i +10;
}

}
}main.xml
中查看了没有错误，怎么办？？

Answer 1

去掉import android.R一行