Question

所以我有一个Fragment Activity，它使用另一个片段键盘向地图添加一个标记，并且我得到一个空指针异常。我还在其主机片段中访问键盘以将数据添加到列表中。要清楚键盘正在被两个片段同时使用。我的代码（这是我从另一个片段访问键盘的片段）：

  @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            final EditText textLat = (EditText)findViewById(R.id.textLat);
            final EditText textLong = (EditText)findViewById(R.id.textLong);
            EditText PO = (EditText)findViewById(R.id.POdata);
            setContentView(R.layout.activity_maps);
            setUpMapIfNeeded();
            mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
            mMap.setMyLocationEnabled(true);
   /*this line throws the error*/PO.setOnKeyListener(new View.OnKeyListener() {
                @Override
                public boolean onKey(View v, int keyCode, KeyEvent event) {
                    if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_DOWN) {
                        int Latitudei = Integer.parseInt(textLat.getText().toString());
                        int Logitudei = Integer.parseInt(textLong.getText().toString());
                        mMap.addMarker(new MarkerOptions().position(new LatLng(Latitudei, Logitudei)));
                    }
                    return false;
                }
            });
        }

这是键盘片段

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            final EditText PO = (EditText)getActivity().findViewById(R.id.POdata);
            EditText textLat = (EditText)getActivity().findViewById(R.id.textLat);
            EditText textLong = (EditText)getActivity().findViewById(R.id.textLong);
            ListView data = (ListView)getActivity().findViewById(R.id.listView);
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
            ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(
                    getActivity(),
                    android.R.layout.simple_list_item_1,
                    POin);
            data.setAdapter(arrayAdapter);

            PO.setOnKeyListener(new View.OnKeyListener() {
                @Override
                public boolean onKey(View v, int keyCode, KeyEvent event) {
                    if (keyCode == KeyEvent.KEYCODE_ENTER && event.getAction() == KeyEvent.ACTION_DOWN) {
                        POin.add(PO.getText().toString());
                    }
                    return false;
                }
            });
        }
    }

堆栈跟踪：

Caused by: java.lang.NullPointerException
            at com.example.adrian.xxxxxxxxxx.MapsActivity.onCreate(MapsActivity.java:31)
            at android.app.Activity.performCreate(Activity.java:5312)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1111)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2552)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2653)
            at android.app.ActivityThread.access$800(ActivityThread.java:156)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1355)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:157)
            at android.app.ActivityThread.main(ActivityThread.java:5872)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:852)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:668)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

A.B.C形式的行上的空指针异常意味着点左侧的某些内容为空。在这个例子中：

A为空;

或A.B为空。

没有其他原因。因此，由于textView.getText（）永远不会返回null，唯一的可能是用户为null。

Android从另一个片段访问键盘时抛出空指针异常

1 个答案: