java Android PDF查看器空对象引用错误

Question

我和其他很多人一样使用barteksc Android PDF Viewer（https://github.com/barteksc/AndroidPdfViewer）。我一直收到一个空对象引用错误。这就是错误所在

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: group6.interactivehandwriting, PID: 24037
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{group6.interactivehandwriting/group6.interactivehandwriting.activities.RoomActivity.RoomActivity}: 安卓.view.InflateException: Binary XML file line #9: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference

我已检查以确保正确引用了视图。我正在加载的名为“sample.pdf”的资产位于我的资产中

*你能看出我收到这个错误的原因吗*

我知道有很多关于这个图书馆的帖子，但是每个例子似乎都是独一无二的，所以我决定继续问

房间活动。爪哇

package group6.interactivehandwriting.activities.RoomActivity;

import 安卓.content.res.AssetManager;
import 安卓.os.Bundle;
import 安卓.app.Activity;
import 安卓.util.Log;
import 安卓.view.View;

import com.github.barteksc.pdfviewer.PDFView;
import com.github.barteksc.pdfviewer.listener.OnLoadCompleteListener;
import com.github.barteksc.pdfviewer.listener.OnPageChangeListener;
import com.github.barteksc.pdfviewer.scroll.DefaultScrollHandle;

import group6.interactivehandwriting.R;
import group6.interactivehandwriting.activities.RoomActivity.views.DocumentView;
import group6.interactivehandwriting.activities.RoomActivity.views.RoomView;

public class RoomActivity extends Activity implements OnPageChangeListener, OnLoadCompleteListener {
    RoomView roomView;
    DocumentView docView;
    PDFView pView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("Android: ", "Setting content view to an instance of RoomView in: " + this.getClass().getName());
        setContentView(R.layout.activity_draw);

        System.out.println("Attempting to set ImageView..");
        pView = (PDFView) findViewById(R.id.pdfView);
        pView.fromAsset("sample.pdf").defaultPage(0)
                .enableSwipe(true).swipeHorizontal(false).
                onPageChange(this).enableAnnotationRendering(true).onLoad(this).scrollHandle(new DefaultScrollHandle(this)).load();


    }

    @Override
    public void onPageChanged(int page, int pageCount) {
        setTitle(String.format("%s %s / %s", "Sample", page + 1, pageCount));
    }

    @Override
    public void loadComplete(int nbPages) {
    }
}

AndroidManifest。xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
    package="group6.interactivehandwriting">

    <uses-permission 安卓:name="安卓.permission.READ_EXTERNAL_STORAGE"/>
    <application
        安卓:allowBackup="true"
        安卓:icon="@mipmap/ic_launcher"
        安卓:label="@string/app_name"
        安卓:roundIcon="@mipmap/ic_launcher_round"
        安卓:supportsRtl="true"
        安卓:theme="@style/AppTheme">
        <activity
            安卓:name=".activities.RoomActivity.RoomActivity"
            安卓:label="@string/title_activity_menu"
            安卓:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action 安卓:name="安卓.intent.action.MAIN" />

                <category 安卓:name="安卓.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

活动：画画。xml

<?xml version="1.0" encoding="utf-8"?>
<安卓.support.constraint.ConstraintLayout xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
    xmlns:app="http://schemas.安卓.com/apk/res-auto"
    xmlns:tools="http://schemas.安卓.com/tools"
    安卓:layout_width="match_parent"
    安卓:layout_height="match_parent"
    tools:context=".activities.RoomActivity.RoomActivity">

    <view
        安卓:id="@+id/room_view"
        id="@+id/view"
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <com.github.barteksc.pdfviewer.PDFView
        安卓:id="@+id/pdfView"
        安卓:layout_width="match_parent"
        安卓:layout_height="match_parent"/>

    <TextView
        安卓:id="@+id/textView"
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        安卓:layout_marginStart="8dp"
        安卓:layout_marginTop="8dp"
        安卓:text="@string/room"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</安卓.support.constraint.ConstraintLayout>

依赖项：

compile 'com.github.barteksc:安卓-pdf-viewer:2.8.2'

compile 'org.apache.commons:commons-collections4:4.1'