空指针异常问题
import android.app.Activity;
import android.content.Intent;
import android.database.CursorJoiner.Result;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Activity05 extends Activity {
private EditText myEditText_01;
private EditText myEditText_02;
private Button myButton;
private TextView myTextView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button myButton=(Button)findViewById(R.id.myButton);
EditText myEditText_01=(EditText)findViewById(R.id.myEditText_01);
EditText myEditText_02=(EditText)findViewById(R.id.myEditText_02);
TextView myTextView = (TextView)findViewById(R.id.myTextView);
myButton.setText(R.string.calculate);
myTextView.setText(R.string.symbol);
myButton.setOnClickListener(new MyButtonListener());
}
public boolean onCreateOptionsMenu(Menu menu) {//click menu ,use this method
menu.add(0, 1, 1,R.string.exit);
menu.add(0, 2, 2, R.string.about);//add 2 times, there are 2 factors
return super.onCreateOptionsMenu(menu);
}
public boolean onOptionsItemSelected(MenuItem item) {//click the factor of menu,use this method
if(item.getItemId()==1){
finish();
}
return super.onOptionsItemSelected(item);
}
class MyButtonListener implements OnClickListener {
public void onClick(View ars0) {
String s1= myEditText_01.getText().toString();
String s2= myEditText_02.getText().toString();
Intent intent=new Intent();
intent.putExtra("one", s1);
intent.putExtra("two", s2);
intent.setClass(Activity05.this, Result.class);
Activity05.this.startActivity(intent);
}
}
}
运行到String s1= myEditText_01.getText().toString();这句话时报错说是nullpointerception.。程序被终止，，跳转不到第二个界面。。
请各位大侠帮忙
[解决办法]
在这一句前面String s1= myEditText_01.getText().toString();用log看看myEditText——01是否为空
[解决办法]
检查你的myEditText是否是对应到视图里面的。。
[解决办法]
EditText myEditText_01=(EditText)findViewById(R.id.myEditText_01);
EditText myEditText_02=(EditText)findViewById(R.id.myEditText_02);
TextView myTextView = (TextView)findViewById(R.id.myTextView);
把红色的去掉
