android - 附加到条形码应用程序中多个按钮的监听器异常

Question

好的，所以我正在为我的公司开发一个内部条形码扫描仪，以便在我们移动计算机和设备时使用。经过一些试验和错误后，我目前几乎通过 Intent 设置了 Zxing 条码扫描仪。

这是我正在尝试做的事情。

在三个 EditText 字段旁边，我有三个 ImageButtons，单击它们时，实现 BarcodeScanner，扫描后返回值并输入值进入 EditText 字段。我能够使用一个对应于一个 ImageButton 的“监听器”成功地做到这一点。但是在尝试对一个监听器使用多个 Button 后，它会调用条形码扫描仪，但在尝试返回条形码值时会崩溃。

调试器显示主线程已暂停，我必须在 Logcat 中出现 RuntimeException 错误之前恢复调试器两次。

这是来自 LogCat 的错误日志:

07-17 17:38:49.251: E/AndroidRuntime(30942): java.lang.RuntimeException: Unable to resume activity {com.fmi.inventory/com.fmi.inventory.MainActivity}: java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=49374, result=-1, data=Intent { act=com.google.zxing.client.android.SCAN flg=0x80000 (has extras) }} to activity {com.fmi.inventory/com.fmi.inventory.MainActivity}: java.lang.NullPointerException

这是我的 MainActivity:

package com.fmi.inventory;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;

public class MainActivity extends Activity {

    ImageButton button;
    ImageButton button1;
    ImageButton button2;
    EditText editField;
    Activity activity;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        activity = this;
        button = (ImageButton)findViewById(R.id.scanCubeID);
        button1 = (ImageButton)findViewById(R.id.scanEmployeeID);
        button2 = (ImageButton)findViewById(R.id.scanConfigID);
        button.setOnClickListener(listener);
        button1.setOnClickListener(listener);
        button2.setOnClickListener(listener);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    @Override
    public void onResume() {
        super.onResume();

    }

    public void setCubeClick(){
        editField = (EditText)findViewById(R.id.editCubeID);
    }

    public void setEmployeeClick(){
        editField = (EditText)findViewById(R.id.editEmployeeID);
    }

    public void setConfigClick(){
        editField = (EditText)findViewById(R.id.editConfigID);
    }

    private View.OnClickListener listener = new View.OnClickListener() {
        public void onClick(View v) {
            IntentIntegrator integrator = new IntentIntegrator(activity);
            integrator.initiateScan();

        }
    };

    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        switch (requestCode) {
        case IntentIntegrator.REQUEST_CODE:
            if (resultCode == Activity.RESULT_OK) {

                IntentResult intentResult = IntentIntegrator
                        .parseActivityResult(requestCode, resultCode, intent);

                if (intentResult != null) {

                    String contents = intentResult.getContents();
                    String format = intentResult.getFormatName();
                    this.editField.setText(contents);
                    // this.elemQuery.setText(contents);
                    //this.resume = false;
                    Log.d("SEARCH_EAN", "OK, EAN: " + contents + ", FORMAT: "
                            + format);
                } else {
                    Log.e("SEARCH_EAN", "IntentResult je NULL!");
                }
            } else if (resultCode == Activity.RESULT_CANCELED) {
                Log.e("SEARCH_EAN", "CANCEL");
            }
        }
    }
}

这是我的 MainActivity 布局 .xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <EditText
        android:id="@+id/editCubeID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/scanEmployeeID"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_toLeftOf="@+id/scanCubeID"
        android:ems="10"
        android:hint="@string/edit_cubeid" >

        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/editEmployeeID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/scanConfigID"
        android:layout_alignParentLeft="true"
        android:layout_alignRight="@+id/editCubeID"
        android:layout_below="@+id/editCubeID"
        android:ems="10"
        android:hint="@string/edit_employeeid" />

    <EditText
        android:id="@+id/editConfigID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/scanConfigID"
        android:layout_alignParentLeft="true"
        android:layout_alignRight="@+id/editEmployeeID"
        android:layout_below="@+id/editEmployeeID"
        android:ems="10"
        android:hint="@string/edit_configid" />

    <ImageButton
        android:id="@+id/scanCubeID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:contentDescription="@string/desc"
        android:layout_alignParentTop="true"
        android:src="@drawable/ic_action_scan"
        android:onClick="onClick" />

    <ImageButton
        android:id="@+id/scanEmployeeID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:contentDescription="@string/desc"
        android:layout_below="@+id/scanCubeID"
        android:src="@drawable/ic_action_scan"
        android:onClick="onClick" />

    <ImageButton
        android:id="@+id/scanConfigID"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:contentDescription="@string/desc"
        android:layout_below="@+id/scanEmployeeID"
        android:src="@drawable/ic_action_scan"
        android:onClick="onClick" />

    <Button
        android:id="@+id/submit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/editConfigID"
        android:text="@string/button_continue" />

</RelativeLayout>

Answer 1

当你的Activity扫描后进入onActivityResult。你正在访问editField，但它是NULL。

因为你从未初始化它..

您正在 setCubeClick、setEmployeeClick 或 setConfigClick 中初始化它们，

但我担心他们从未调用过..尝试在OnCreat中Initialize他们