我在教程后写了一个witre / read android应用程序，但为了我的目的改变了一些东西。 应用程序启动时会崩溃

Question

我不认为我的其他任何代码都会崩溃应用程序，因为它甚至在启动之前就崩溃了。 类似问题的其他解决方案已经说过它因为setContentView（R.layout.yourlayout）但我使用了我的布局，所以我不认为这将是问题。

public class WriteRead extends Activity实现OnClickListener {

public Button btnSave = (Button) findViewById(R.id.btnSave);
public Button btnNext = (Button) findViewById(R.id.btnNext);
public EditText Name = (EditText) findViewById(R.id.editText1); 
public EditText DOB = (EditText) findViewById(R.id.editText2); 
public EditText HealthNum = (EditText) findViewById(R.id.editText3); 
public EditText Arrival = (EditText) findViewById(R.id.editText4); 
public EditText HeartRate = (EditText) findViewById(R.id.editText5); 
public EditText Temp = (EditText) findViewById(R.id.editText6); 
public EditText BPressure = (EditText) findViewById(R.id.editText7); 
String nametxt = Name.getText().toString();
String healthCardtxt = HealthNum.getText().toString();
String dobtxt = DOB.getText().toString();
String arrivaltxt = Arrival.getText().toString();
String heartRatetxt = HeartRate.getText().toString();
String Temptxt = Temp.getText().toString();; 
String bptxt = BPressure.getText().toString();


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_write_read);

Answer 1

这应该继续onCreate

public Button btnSave = (Button) findViewById(R.id.btnSave);
public Button btnNext = (Button) findViewById(R.id.btnNext);
public EditText Name = (EditText) findViewById(R.id.editText1); 
public EditText DOB = (EditText) findViewById(R.id.editText2); 
public EditText HealthNum = (EditText) findViewById(R.id.editText3); 
public EditText Arrival = (EditText) findViewById(R.id.editText4); 
public EditText HeartRate = (EditText) findViewById(R.id.editText5); 
public EditText Temp = (EditText) findViewById(R.id.editText6); 
public EditText BPressure = (EditText) findViewById(R.id.editText7);