Iam試圖將用戶輸入值從一個活動傳遞給另一個活動。在第二次活動中,Iam對數據進行一些操作並顯示最終值。但它正在給出一個空投影。請幫我調試錯誤:java.lang.NullPointerException
我的代碼中有什麼錯誤?
第一活動:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fourth);
final EditText et;
final Button b;
et = (EditText) findViewById(R.id.editText1);
b = (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v)
{
Intent intent = new Intent(Fourth.this, Fifth.class);
intent.putExtra("thetext", et.getText().toString());
startActivity(intent);
Intent intentnew = new Intent(Fourth.this, Sixth.class);
intentnew.putExtra("thetext", et.getText().toString());
startActivity(intentnew);
}
其中數據被接收並顯示的下一個活動(代碼段)
TextView tvr = (TextView) findViewById(R.id.finalremark);
double wto=Double.parseDouble(getIntent().getExtras().getString("the text"));
double z=wto*0.75;
String weight= Double.toString(z);
tvr.setText(weight);
的logcat的
09-03 11:11:06.069: E/AndroidRuntime(30262): FATAL EXCEPTION: main
09-03 11:11:06.069: E/AndroidRuntime(30262): java.lang.NullPointerException
09-03 11:11:06.069: E/AndroidRuntime(30262): at com.example.footforthought.Sixth$2.handleMessage(Sixth.java:380)
09-03 11:11:06.069: E/AndroidRuntime(30262): at android.os.Handler.dispatchMessage(Handler.java:99)
09-03 11:11:06.069: E/AndroidRuntime(30262): at android.os.Looper.loop(Looper.java:137)
09-03 11:11:06.069: E/AndroidRuntime(30262): at android.app.ActivityThread.main(ActivityThread.java:4517)
09-03 11:11:06.069: E/AndroidRuntime(30262): at java.lang.reflect.Method.invokeNative(Native Method)
09-03 11:11:06.069: E/AndroidRuntime(30262): at java.lang.reflect.Method.invoke(Method.java:511)
09-03 11:11:06.069: E/AndroidRuntime(30262): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
09-03 11:11:06.069: E/AndroidRuntime(30262): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
09-03 11:11:06.069: E/AndroidRuntime(30262): at dalvik.system.NativeStart.main(Native Method)
09-03 11:11:17.969: I/Process(30262): Sending signal. PID: 30262 SIG: 9
張貼您的logcat – 2014-09-03 05:56:54
並標記您的NPE來自哪裏。 – Jens 2014-09-03 05:58:16
您可以同時開始兩項活動。爲什麼? – 2014-09-03 06:02:36