一个意图是有效的，第二个是给我一个崩溃

Question

接收端有两个意图，它们从同一活动调用，并将数据发送到不同的活动。第二个意图不起作用。第一个是。我不知道为什么。所有活动和清单似乎都是正确的。

//second intent on senders side    
        public void onItemSelected(AdapterView<?> arg0, View users, int i,
                        long l) {
                    FILENAME = (adapter.getItem(i)).toString();
            Bundle viewBag2 = new Bundle();
                        viewBag2.putString("profile_name", FILENAME);
                        Intent b = new Intent(OptionsMenu.this, CoreActivity.class);
                        b.putExtras(viewBag2);  
                        startActivity(b);
              }

    //second intent on receiver side
        private void Data_transfer() {
        Bundle gotbasket2 = getIntent().getExtras();
                profileName = gotbasket2.getString("profile_name");
        }
    //first (working intent) on senders side
        public void onClick(View v) {
                    Bundle viewBag = new Bundle();
                    viewBag.putString("spinner_result", s);
    a.putExtras(viewBag);
    }

    //first (working intent) on receiver side
        private void Data_transfer() {
            // TODO Auto-generated method stub
            Bundle gotbasket = getIntent().getExtras();
            x = gotbasket.getString("spinner_result");
    }

下面是附加的日志猫。

 06-26 20:22:09.787: D/AndroidRuntime(1802): Shutting down VM
    06-26 20:22:09.787: W/dalvikvm(1802): threadid=1: thread exiting with uncaught exception (group=0x40015560)
    06-26 20:22:09.847: E/AndroidRuntime(1802): FATAL EXCEPTION: main
    06-26 20:22:09.847: E/AndroidRuntime(1802): java.lang.RuntimeException: Unable to start activity ComponentInfo{mioc.diver/mioc.diver.CoreActivity}: java.lang.NullPointerException
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.os.Handler.dispatchMessage(Handler.java:99)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.os.Looper.loop(Looper.java:123)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.ActivityThread.main(ActivityThread.java:3683)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at java.lang.reflect.Method.invokeNative(Native Method)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at java.lang.reflect.Method.invoke(Method.java:507)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at dalvik.system.NativeStart.main(Native Method)
    06-26 20:22:09.847: E/AndroidRuntime(1802): Caused by: java.lang.NullPointerException
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at mioc.diver.CoreActivity.Data_transfer(CoreActivity.java:189)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at mioc.diver.CoreActivity.onCreate(CoreActivity.java:88)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
    06-26 20:22:09.847: E/AndroidRuntime(1802):     ... 11 more

Answer 1

首先，您不需要每次想要在意图中添加额外的内容时都创建一个新的捆绑包。你可以做：

Intent b = new Intent(OptionsMenu.this, CoreActivity.class);
b.putExtra(key, value);

其次，方法名称不应该以大写字母开头，如Google Java风格指南中所述。

最后，您似乎在 Data_transfer（） 中得到了一个 NullPointerException，这意味着您在 Activity 的第 189 行（可能是 FILENAME）有一个 null 变量。