Question

我有三项活动。我将一个对象从一个活动发送到第二个活动。我使用onActivityResult从第二个活动检索数据。然后我需要将我检索到的数据发送到第三个活动，但我有一个例外。

主要活动（问题是实施parcelable的类。您可以在其他问题First question中看到：

public class MainActivity extends Activity {

Tgestion Tges= new Tgestion();
Button buttonI,buttonM,buttonB,buttonD,buttonS;
static final int RECUPERAR_GESTOR = 1;
static final int RECUPERAR_MODIFICAR=1;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    addListenerOnButton();

}

public void addListenerOnButton() {

    final Context context = this;

    buttonI = (Button) findViewById(R.id.buttonIntroducir);
    buttonI.setEnabled(true);

    buttonI.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {

            Intent intent = new Intent(context, IntroducirPatron.class);
            intent.putExtra("com.example.sistemacontrasena.gestion", Tges);
            //startActivity(intent); 
            startActivityForResult(intent, RECUPERAR_GESTOR);

        }

    });

    buttonM = (Button) findViewById(R.id.buttonModificar);
    buttonM.setEnabled(false);

    buttonM.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {


            Intent intent2 = new Intent(context, ModificarPatron.class);
            intent2.putExtra("com.example.sistemacontrasena.mod", Tges);
            startActivityForResult(intent2, RECUPERAR_MODIFICAR);   

        }

    });


}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // Check which request we're responding to
    if (requestCode == RECUPERAR_GESTOR) {
        // Make sure the request was successful
        if (resultCode == RESULT_OK) {
            this.Tges=data.getParcelableExtra("com.example.sistemacontrasena.result_gestion");


        }
        if (resultCode == RESULT_CANCELED) {
            //Write your code if there's no result
        }
    }               
}
}

在第二个活动中我放了setResult：

Intent returnIntent = new Intent();
    returnIntent.putExtra("com.example.sistemacontrasena.result_gestion", this.gestion);
    setResult(RESULT_OK, returnIntent);
    return maximo;

直到这里一切都是正确的在第三个活动中我使用：

Tgestion gestion2;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_modificar_patron);
      this.gestion2=getIntent().getParcelableExtra("com.example.sistemacontrasena.mod");

}

但是当我在第三个活动中调用question2的函数时，例如：

 String[] prueba= new String[2];
 prueba=this.gestion2.getSecret();
 System.out.println(prueba[0])

我有一个例外：

06-15 13:37:44.852: E/AndroidRuntime(32262): FATAL EXCEPTION: main
06-15 13:37:44.852: E/AndroidRuntime(32262): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sistemacontrasena/com.example.sistemacontrasena.ModificarPatron}: java.lang.NullPointerException
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1659)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1675)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.ActivityThread.access$1500(ActivityThread.java:121)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:943)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.os.Looper.loop(Looper.java:138)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.ActivityThread.main(ActivityThread.java:3701)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at java.lang.reflect.Method.invokeNative(Native Method)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at java.lang.reflect.Method.invoke(Method.java:507)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at dalvik.system.NativeStart.main(Native Method)
06-15 13:37:44.852: E/AndroidRuntime(32262): Caused by: java.lang.NullPointerException
06-15 13:37:44.852: E/AndroidRuntime(32262):    at com.example.sistemacontrasena.ModificarPatron.onCreate(ModificarPatron.java:35)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
06-15 13:37:44.852: E/AndroidRuntime(32262):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
06-15 13:37:44.852: E/AndroidRuntime(32262):    ... 11 more

我需要通过主要活动使用从第二个活动检索到第三个活动的信息。

Answer 1

您在第3个活动中的gestion2引用上获得了nullpointerexception。 getParcelableExtra（＆＃34; com.example.sistemacontrasena.mod＆＃34; ）中使用的密钥不包含任何值，因为您还没有为此密钥分配任何值。

只需确保您用于检索值的密钥已经在调用活动意图中分配了一些值。

如果您调用任何方法的任何引用/对象为null，请输入正确的日志以检查空值。

从两个以上的活动中传递和检索参数

1 个答案: