public class MainScreen extends AppCompatActivity {
private double mmiles,mgallons = 1;
EditText miles;
EditText gallons;
Button execute;
TextView fin;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_screen);
execute.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view){
miles = (EditText) findViewById(R.id.editTextMiles);
gallons = (EditText) findViewById(R.id.editTextGallons);
mmiles = Double.parseDouble(miles.getText().toString());
execute= (Button) findViewById(R.id.execute);
fin= (TextView) findViewById(R.id.fini);
String numberAsString = new Double(mmiles).toString();
fin.setText(numberAsString);
}
});
}}
每當我啓動應用程序時,它都會崩潰。我試圖從一個EditText存儲一個數字到一個TextView開始。我是java編程的新手,所以我很難搞清楚這一點。當我嘗試運行它時,我的應用會一直崩潰(新增功能)
編輯:仍然似乎不顯示任何東西。這是我到目前爲止有:
execute.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view){
miles = (EditText) findViewById(R.id.editTextMiles);
gallons = (EditText) findViewById(R.id.editTextGallons);
mmiles = Double.parseDouble(miles.getText().toString());
String TextAsString = String.valueOf(mmiles);
fin= (TextView) findViewById(R.id.fini);
fin.setText(TextAsString);
}
});
什麼是錯誤? – ifly6
請檢查android監視器中的錯誤並粘貼日誌 – surya
因爲'execute'是'null'。移動'execute =(Button)findViewById(R.id.execute);'setContentView'後面的行 –