Olá, estou estudando Android e quero fazer uma simples passagem de parâmetro para outra Activity mas a aplicação é finalizada no emulador e o logCat mostra um Null pointer Exception, alguém pode me ajudar? Classe
public class MainActivity extends Activity {
EditText num1 = (EditText) findViewById(R.id.txtNumber1);
EditText num2 = (EditText) findViewById(R.id.txtNumber2);
String n1= num1.getText().toString();
int numero1 = Integer.parseInt(n1);
String n2= num2.getText().toString();
int numero2 = Integer.parseInt(n1);
int soma=numero1+numero2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button bt = (Button) findViewById(R.id.bt1);
final Intent it = new Intent(this, Cadastros.class);
bt.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
it.putExtra("Total", soma);
startActivity(it);
}
});
}
XML
<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout
android:id="@+id/widget0"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<Button
android:id="@+id/bt1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click"
android:gravity="center"
android:layout_x="134dp"
android:layout_y="102dp" />
<EditText
android:id="@+id/txtNumber1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_x="56dp"
android:layout_y="179dp"
android:ems="10"
android:inputType="number" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/txtNumber2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_x="69dp"
android:layout_y="222dp"
android:ems="10"
android:inputType="number" />
</AbsoluteLayout>
Log
06-16 08:09:48.240: D/AndroidRuntime(948): Shutting down VM
06-16 08:09:48.270: W/dalvikvm(948): threadid=1: thread exiting with uncaught exception (group=0x41465730)
06-16 08:09:48.330: E/AndroidRuntime(948): FATAL EXCEPTION: main
06-16 08:09:48.330: E/AndroidRuntime(948): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{br.com.passagemparam/br.com.passagemparam.MainActivity}: java.lang.NullPointerException
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.ActivityThread.access$600(ActivityThread.java:141)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.os.Looper.loop(Looper.java:137)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.ActivityThread.main(ActivityThread.java:5103)
06-16 08:09:48.330: E/AndroidRuntime(948): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 08:09:48.330: E/AndroidRuntime(948): at java.lang.reflect.Method.invoke(Method.java:525)
06-16 08:09:48.330: E/AndroidRuntime(948): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
06-16 08:09:48.330: E/AndroidRuntime(948): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 08:09:48.330: E/AndroidRuntime(948): at dalvik.system.NativeStart.main(Native Method)
06-16 08:09:48.330: E/AndroidRuntime(948): Caused by: java.lang.NullPointerException
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.Activity.findViewById(Activity.java:1853)
06-16 08:09:48.330: E/AndroidRuntime(948): at br.com.passagemparam.MainActivity.<init>(MainActivity.java:14)
06-16 08:09:48.330: E/AndroidRuntime(948): at java.lang.Class.newInstanceImpl(Native Method)
06-16 08:09:48.330: E/AndroidRuntime(948): at java.lang.Class.newInstance(Class.java:1130)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
06-16 08:09:48.330: E/AndroidRuntime(948): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
06-16 08:09:48.330: E/AndroidRuntime(948): ... 11 more
Cadastro XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/label1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Fala Fera"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/mostraTotal"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
String XML
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Passagem param</string>
<string name="hello_world">Hello world!</string>
<string name="action_settings">Settings</string>
</resources>
Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="br.com.passagemparam"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="Cadastros">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
</intent-filter>
</activity>
</application>
</manifest>
LogCAt
06-16 13:06:43.040: E/AndroidRuntime(859): FATAL EXCEPTION: main
06-16 13:06:43.040: E/AndroidRuntime(859): java.lang.RuntimeException: Unable to start activity ComponentInfo{br.com.passagemparam
/br.com.passagemparam.Cadastros}: android.content.res.Resources$NotFoundException: String resource ID #0x8
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.ActivityThread.access$600(ActivityThread.java:141)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.os.Handler.dispatchMessage(Handler.java:99)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.os.Looper.loop(Looper.java:137)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.ActivityThread.main(ActivityThread.java:5103)
06-16 13:06:43.040: E/AndroidRuntime(859): at java.lang.reflect.Method.invokeNative(Native Method)
06-16 13:06:43.040: E/AndroidRuntime(859): at java.lang.reflect.Method.invoke(Method.java:525)
06-16 13:06:43.040: E/AndroidRuntime(859): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
06-16 13:06:43.040: E/AndroidRuntime(859): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-16 13:06:43.040: E/AndroidRuntime(859): at dalvik.system.NativeStart.main(Native Method)
06-16 13:06:43.040: E/AndroidRuntime(859): Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x8
06-16 13:06:43.040: E/AndroidRuntime(859): at android.content.res.Resources.getText(Resources.java:239)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.widget.TextView.setText(TextView.java:3844)
06-16 13:06:43.040: E/AndroidRuntime(859): at br.com.passagemparam.Cadastros.onCreate(Cadastros.java:23)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.Activity.performCreate(Activity.java:5133)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
06-16 13:06:43.040: E/AndroidRuntime(859): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
06-16 13:06:43.040: E/AndroidRuntime(859): ... 11 more