当我尝试开始这个活动时,它没有运行。
LogCat 显示以下错误:
07-25 12:10:46.813: E/AndroidRuntime(797): FATAL EXCEPTION: main
07-25 12:10:46.813: E/AndroidRuntime(797): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.testingandroid/com.example.testingandroid.DoSums}: java.lang.NullPointerException
我的代码:
public class DoSums extends Activity implements OnClickListener {
public RadioButton r1 = (RadioButton) findViewById(R.id.doradioButton1);
public RadioButton r2 = (RadioButton) findViewById(R.id.doradioButton2);
public RadioButton r3 = (RadioButton) findViewById(R.id.doradioButton3);
public RadioButton r4 = (RadioButton) findViewById(R.id.doradioButton4);
public EditText et = (EditText) findViewById(R.id.doeditText1);
//Button btnNextScreen = (Button) findViewById(R.id.button1);
timeanddistanceM pen = new timeanddistanceM();
public String Q, A, finalvalue, scale;
public double fv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_do_sums);
objCreator();
//btnNextScreen.setOnClickListener(this);
r1.setOnClickListener(this);
r2.setOnClickListener(this);
r3.setOnClickListener(this);
r4.setOnClickListener(this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.do_sums, menu);
return true;
}
public void objCreator() {
pen.timeanddistanceM();
// Setting question
String Q = pen.Q;
et.setText("Question" + Q);
// Setting options
// 1. Getting options
options ops = new options();
ops.optionsCreator(pen.fv, pen.scale);
// 2.Assigning options
r1.setText(ops.jRadioButton1);
r2.setText(ops.jRadioButton2);
r3.setText(ops.jRadioButton3);
r4.setText(ops.jRadioButton4);
}
public void RadiobuttonAction(RadioButton testRadio) {
if (testRadio.getText().toString().equals(pen.finalvalue)) {
objCreator();
}
}
@Override
public void onClick(View arg0) {
switch (arg0.getId()) {
/*case R.id.doradioButton1:
pen.timeanddistanceM();
String Q = pen.Q;
et.setText("Question" + Q);
break;*/
case R.id.doradioButton1:
RadiobuttonAction(r1);
break;
case R.id.doradioButton2:
RadiobuttonAction(r2);
break;
case R.id.doradioButton3:
RadiobuttonAction(r3);
break;
case R.id.doradioButton4:
RadiobuttonAction(r4);
break;
}
}
}