AutocompleteSupportFragment.setPlaceFields 在启动时粉碎 App

Question

首先，我想说我是这个“编程世界”的新手，但我一直在努力使用 google Places 的 autocompleteFragment， 我正在尝试在我的应用程序中实现 autocompleteFragment，但在进入我的“欢迎活动”后，它会引发错误并破坏应用程序：

    Process: com.app.mk.transport, PID: 20295
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.mk.transport/com.app.mk.transport.Welcome}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.libraries.places.widget.AutocompleteSupportFragment.setPlaceFields(java.util.List)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.libraries.places.widget.AutocompleteSupportFragment.setPlaceFields(java.util.List)' on a null object reference
        at com.app.mk.transport.Welcome.setUpLocationPicker(Welcome.java:237)
        at com.app.mk.transport.Welcome.onCreate(Welcome.java:216)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

这是我的代码：

        if (!Places.isInitialized()) {
            Places.initialize(getApplicationContext(), String.valueOf(R.string.google_api_key));
        }
            autocompleteFragment.setPlaceFields(Arrays.asList(Place.Field.ADDRESS));


        autocompleteFragment.setOnPlaceSelectedListener(new PlaceSelectionListener() {

            @Override
            public void onPlaceSelected(Place place) {

                if (location_switch.isChecked()) {
                    destination = place.getAddress();
                    destination = destination.replace(" ", "+");
                    getDirection();
                }
            }

            @Override
            public void onError(Status status) {
                // TODO: Handle the error.
                Toast.makeText(Welcome.this, "" + status.toString(), Toast.LENGTH_SHORT).show();
                Log.i(TAG, "An error occurred: " + status);
            }
        });

我不确定我做错了什么，但如果有人能指出我的错误，我将不胜感激。

如果我需要向您展示其他“代码”或任何内容，请告诉我是否遗漏了它！

谢谢。

Answer 1

您好，在片段中实现时会出现此问题。使用 getChildFragmentManager 而不是 getSupportFragmentManager/getFragmentManger()。 这将完美地工作。像这样：-

if (!Places.isInitialized()) {
        Places.initialize(getApplicationContext(), "YOUR_API_KEY");
    }


// Initialize the AutocompleteSupportFragment.

AutocompleteSupportFragment autocompleteFragment = (AutocompleteSupportFragment)
        getChildFragmentManager().findFragmentById(R.id.autocomplete_fragment);


autocompleteFragment.setPlaceFields(Arrays.asList(Place.Field.ID, Place.Field.NAME));


autocompleteFragment.setOnPlaceSelectedListener(new PlaceSelectionListener() {
    @Override
    public void onPlaceSelected(Place place) {
        // TODO: Get info about the selected place.
        Log.i(TAG, "Place: " + place.getName() + ", " + place.getId());
    }

    @Override
    public void onError(Status status) {
        // TODO: Handle the error.
        Log.i(TAG, "An error occurred: " + status);
    }
});

这对我有用，希望这也对你有用。谢谢....

Answer 2

如果您正在使用进入活动，则使用<androidx.fragment.app.FragmentContainerView> 而不是< <fragment> 标记。

并为添加实现“androidx.fragment:fragment:1.2.0”依赖。