条码扫描器 zxing 在启动时崩溃

Question

The application crash on startup. Tried to pull out only the piece of code from the official :zxing-sample

So my activity_main.xml code is from the example such as

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <android.support.design.widget.AppBarLayout
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
    </android.support.design.widget.AppBarLayout>

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <FrameLayout
            android:id="@+id/content_frame"
            android:layout_weight="1"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
        <LinearLayout
            android:orientation="horizontal"
            android:gravity="center"
            android:background="#222"
            android:layout_width="match_parent"
            android:layout_height="150dp">
            <Button
                android:text="Koristiti kameru"
                android:layout_weight="1"
                android:onClick="toggleFlash"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
        </LinearLayout>
    </LinearLayout>
</LinearLayout>

Also in my java file MainActivity.java

package com.example.myapplication;

import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import com.google.zxing.Result;

import me.dm7.barcodescanner.zxing.ZXingScannerView;

public class MainActivity extends BaseScannerActivity implements ZXingScannerView.ResultHandler {

    private ZXingScannerView mScannerView;
    private boolean mFlash;
    private static final String FLASH_STATE = "FLASH_STATE";

    @Override
    public void onCreate(Bundle state) {
        super.onCreate(state);
        setContentView(R.layout.activity_main);
        ViewGroup contentFrame = (ViewGroup) findViewById(R.id.content_frame);
        mScannerView = new ZXingScannerView(this);
        contentFrame.addView(mScannerView);
    }

    @Override
    public void onResume() {
        super.onResume();
        mScannerView.setResultHandler(this);
        // You can optionally set aspect ratio tolerance level
        // that is used in calculating the optimal Camera preview size
        mScannerView.setAspectTolerance(0.2f);
        mScannerView.startCamera();
        mScannerView.setFlash(mFlash);
    }

    @Override
    public void onPause() {
        super.onPause();
        mScannerView.stopCamera();
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean(FLASH_STATE, mFlash);
    }

    @Override
    public void handleResult(Result rawResult) {
        Toast.makeText(this, "Contents = " + rawResult.getText() +
                ", Format = " + rawResult.getBarcodeFormat().toString(), Toast.LENGTH_SHORT).show();

        // Note:
        // * Wait 2 seconds to resume the preview.
        // * On older devices continuously stopping and resuming camera preview can result in freezing the app.
        // * I don't know why this is the case but I don't have the time to figure out.
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                mScannerView.resumeCameraPreview(MainActivity.this);
            }
        }, 2000);
    }

    public void toggleFlash(View v) {
        mFlash = !mFlash;
        mScannerView.setFlash(mFlash);
    }
}

So even after trying to pull out the code from sample i'm still doing something wrong and can't figure out what.

The application crash on startup so i think its a big problem which prevents me from testing the app.

Error SS:

Edit 1 : Asked for permission

public void launchActivity( ) {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
            != PackageManager.PERMISSION_GRANTED) {
         ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.CAMERA}, ZXING_CAMERA_PERMISSION);
    } else {

    }
}

Answer 1

在您的应用程序 Gradle 文件中，检查您的dependencies是否有implementation 'com.android.support:design:28.0.0'

Answer 2

Looking at your Logcat, it shows what's the issue.

    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: android.view.InflateException: Binary XML file line #9: Binary XML file line #9: Error inflating class android.support.design.widget.AppBarLayout
     ...
     Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.design.widget.AppBarLayout" on path: DexPathList[[zip file "/data/app/com.example.myapplication-y9OZiywnTa-bCM9Op2luAw==/base.apk"],nativeLibraryDirectories=[/data/app/com.example.myapplication-y9OZiywnTa-bCM9Op2luAw==/lib/arm, /system/lib, /vendor/lib]]

So, what this means is that it was unable to start your Activity, MainAcitivty , because it could not find the class AppBarLayout . You may be missing a dependency.