应用程序崩溃是因为Fragment？错误膨胀类碎片

Question

我使用了导航抽屉应用程序/项目。我只是按照我在教程中所做的那样（他们只是使用了一个不使用导航抽屉的简单项目）但是当我尝试在导航抽屉中实现它时它会崩溃。我不知道它崩溃的原因，但我认为这是碎片。

我想要发生的是：在应用程序启动时显示片段，这就是我在导航抽屉中使用'content_main.xml'的原因（我是否正确？那是显示启动内容的那个）运行应用程序？）。

我的MainActivity代码采用'onCreate'方法：

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

我的searchFragment代码：

package rjj.sampleproject;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;


import com.weiwangcn.betterspinner.library.material.MaterialBetterSpinner;

public class searchFragment extends Fragment {
    private searcher searcherImplementer;
    public interface searcher{
        public void searchForRoutesCategory(String route, String category);
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        this.searcherImplementer =(searcher)context;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.activity_search_category, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Button flightSearchButton = (Button)getActivity().findViewById(R.id.button2);
        flightSearchButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                MaterialBetterSpinner route = (MaterialBetterSpinner)getActivity().findViewById(R.id.spinner_routes);
                MaterialBetterSpinner category = (MaterialBetterSpinner)getActivity().findViewById(R.id.spinner_category);

                searcherImplementer.searchForRoutesCategory(route.getText().toString(),category.getText().toString());


            }
        });
    }
}

我的content_main.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="rjj.sampleproject.MainActivity"
    tools:showIn="@layout/app_bar_main">

    <fragment
        android:id="@+id/fragment"
        android:name="rjj.sampleproject.searchFragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentEnd="true" />
</RelativeLayout>

我的activity_search_category.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <com.weiwangcn.betterspinner.library.material.MaterialBetterSpinner
        android:id="@+id/spinner_category"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:hint="Select Category"
        />
    <com.weiwangcn.betterspinner.library.material.MaterialBetterSpinner
        android:id="@+id/spinner_routes"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:layout_below="@id/spinner_category"
        android:hint="Select Routes"
        />
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        android:onClick="search"
        android:layout_below="@+id/spinner_routes"
        android:layout_centerHorizontal="true" />

    <Button
        android:id="@+id/showAllRoutes"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/button2"
        android:layout_alignParentStart="true"
        android:layout_marginStart="10dp"
        android:text="Show All Routes"
        android:onClick="showAllRoutes"/>
</RelativeLayout>

我收到的错误：

08-19 15:04:45.281 3388-3394/? E/jdwp: Failed sending reply to debugger: Broken pipe
08-19 15:04:45.351 3388-3388/? E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering
08-19 15:04:45.471 3388-3388/? E/EGL_emulation: tid 3388: eglSurfaceAttrib(1199): error 0x3009 (EGL_BAD_MATCH)
08-19 15:04:45.531 3388-3388/? E/AndroidRuntime: FATAL EXCEPTION: main
                                                 Process: rjj.sampleproject, PID: 3388
                                                 java.lang.NullPointerException
                                                     at android.widget.AutoCompleteTextView.performFiltering(AutoCompleteTextView.java:858)
                                                     at com.weiwangcn.betterspinner.library.material.MaterialBetterSpinner.onFocusChanged(MaterialBetterSpinner.java:49)
                                                     at android.view.View.handleFocusGainInternal(View.java:4617)
                                                     at android.view.View.requestFocusNoSearch(View.java:6999)
                                                     at android.view.View.requestFocus(View.java:6978)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2373)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2370)
                                                     at android.view.ViewGroup.onRequestFocusInDescendants(ViewGroup.java:2414)
                                                     at android.view.ViewGroup.requestFocus(ViewGroup.java:2373)
                                                     at android.view.View.requestFocus(View.java:6945)
                                                     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1828)
                                                     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
                                                     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670)
                                                     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
                                                     at android.view.Choreographer.doCallbacks(Choreographer.java:574)
                                                     at android.view.Choreographer.doFrame(Choreographer.java:544)
                                                     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
                                                     at android.os.Handler.handleCallback(Handler.java:733)
                                                     at android.os.Handler.dispatchMessage(Handler.java:95)
                                                     at android.os.Looper.loop(Looper.java:136)
                                                     at android.app.ActivityThread.main(ActivityThread.java:5017)
                                                     at java.lang.reflect.Method.invokeNative(Native Method)
                                                     at java.lang.reflect.Method.invoke(Method.java:515)
                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
                                                     at dalvik.system.NativeStart.main(Native Method)

MaterialBetterSpinner.java代码：

package com.weiwangcn.betterspinner.library.material;

import android.content.Context;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.content.ContextCompat;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;

import com.rengwuxian.materialedittext.MaterialAutoCompleteTextView;

import java.util.Calendar;


public class MaterialBetterSpinner extends MaterialAutoCompleteTextView implements AdapterView.OnItemClickListener {

    private static final int MAX_CLICK_DURATION = 200;
    private long startClickTime;
    private boolean isPopup;

    public MaterialBetterSpinner(Context context) {
        super(context);
        setOnItemClickListener(this);
    }

    public MaterialBetterSpinner(Context arg0, AttributeSet arg1) {
        super(arg0, arg1);
        setOnItemClickListener(this);
    }

    public MaterialBetterSpinner(Context arg0, AttributeSet arg1, int arg2) {
        super(arg0, arg1, arg2);
        setOnItemClickListener(this);
    }

    @Override
    public boolean enoughToFilter() {
        return true;
    }

    @Override
    protected void onFocusChanged(boolean focused, int direction,
                                  Rect previouslyFocusedRect) {
        super.onFocusChanged(focused, direction, previouslyFocusedRect);
        if (focused) {
            performFiltering("", 0);
            InputMethodManager imm = (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(getWindowToken(), 0);
            setKeyListener(null);
            dismissDropDown();
        } else {
            isPopup = false;
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN: {
                startClickTime = Calendar.getInstance().getTimeInMillis();
                break;
            }
            case MotionEvent.ACTION_UP: {
                long clickDuration = Calendar.getInstance().getTimeInMillis() - startClickTime;
                if (clickDuration < MAX_CLICK_DURATION) {
                    if (isPopup) {
                        dismissDropDown();
                        isPopup = false;
                    } else {
                        requestFocus();
                        showDropDown();
                        isPopup = true;
                    }
                }
            }
        }

        return super.onTouchEvent(event);
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        isPopup = false;
    }

    @Override
    public void setCompoundDrawablesWithIntrinsicBounds(Drawable left, Drawable top, Drawable right, Drawable bottom) {
        Drawable dropdownIcon = ContextCompat.getDrawable(getContext(), R.drawable.ic_expand_more_black_18dp);
        if (dropdownIcon != null) {
            right = dropdownIcon;
            right.mutate().setAlpha(66);
        }
        super.setCompoundDrawablesWithIntrinsicBounds(left, top, right, bottom);
    }

}

Answer 1

您的MainActivity应该实施searchFragment.searcher并覆盖 searchForRoutesCategory方法

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener
                  ,searchFragment.searcher {
//                 ^^^^^^^^^^^^^^^^^^^^^^^

否则你试图从不存在的活动中找到searcher

@Override
public void onAttach(Context context) {
    super.onAttach(context);
    this.searcherImplementer =(searcher)context;
    // crash , searcher not implemented by Activity  ^^^^^^^^^^^^^^
}

更新：从Repository docs开始，您需要设置适配器并将其与MaterialBetterSpinner

绑定

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                 android.R.layout.simple_dropdown_item_1line, COUNTRIES);
         BetterSpinner textView = (BetterSpinner)
                 findViewById(R.id.countries_list);
         textView.setAdapter(adapter);
     }

     private static final String[] COUNTRIES = new String[] {
         "Belgium", "France", "Italy", "Germany", "Spain"
     };

因此您需要在onCreateView内初始化它们，它们是您的片段布局的一部分，而不是活动的一部分，因此(MaterialBetterSpinner)getActivity().不正确

Answer 2

修改

你去了：

这是根据我的编码修改的片段文件：

public class SearchFragment extends Fragment {
    private searcher searcherImplementer;
    private View mView;
    private MaterialBetterSpinner route, category;

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        this.searcherImplementer = (searcher) context;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        if (mView == null) {
            mView = inflater.inflate(R.layout.activity_search_category, container, false);
        }
        String[] list = getResources().getStringArray(R.array.month);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_dropdown_item_1line, list);
        category = (MaterialBetterSpinner) mView.findViewById(R.id.spinner_category);
        route = (MaterialBetterSpinner) mView.findViewById(R.id.spinner_routes);

        route.setAdapter(adapter);
        category.setAdapter(adapter);

        Button flightSearchButton = (Button) mView.findViewById(R.id.button2);
        flightSearchButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                searcherImplementer.searchForRoutesCategory(route.getText().toString(), category.getText().toString());
            }
        });
        return mView;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

    }
}

我认为你唯一的错误就是没有为任何MaterialBetterSpinner设置适配器。希望这适合你:-)试一试。如果您仍然遇到任何问题，请告诉我。

<强> OLD

尝试添加像这样的片段运行时：

您的content_main.xml将是这样的：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/llMain"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <FrameLayout
        android:id="@+id/frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </FrameLayout>

</RelativeLayout>

然后从你的活动中添加这样的片段：

    searchFragment fragment = new searchFragment();
    FragmentTransaction fragmentTransaction=getSupportFragmentManager().beginTransaction();
    fragmentTransaction.setCustomAnimations(R.anim.fade_in, R.anim.fade_out, R.anim.fade_in, R.anim.fade_out);
    fragmentTransaction.add(R.id.frame,fragment, fragment.getClass().getName());
    fragmentTransaction.commit();

Answer 3

我终于设法显示片段并通过在searchFragment.java类中添加适配器来修复错误。

代码是：

 ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(),
                android.R.layout.simple_expandable_list_item_1, ROUTES);
        MaterialBetterSpinner betterSpinner = (MaterialBetterSpinner)view.findViewById(R.id.spinner_routes);
        betterSpinner.setAdapter(adapter);