Android 从活动中呼叫zxing
我创建了一个使用导航抽屉和内部静态片段的活动Android 从活动中呼叫zxing,android,android-activity,android-fragments,zxing,Android,Android Activity,Android Fragments,Zxing,我创建了一个使用导航抽屉和内部静态片段的活动 @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = null; switch (SectionNumber) {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = null;
switch (SectionNumber)
{
case 1:
rootView = inflater.inflate(R.layout.fragment_main, container, false);
break;
case 2:
rootView = inflater.inflate(R.layout.fragment_movement, container, false);
movementActivity = new MovementActivity(context);
movementActivity .setUp();
break;
case 3:
rootView = inflater.inflate(R.layout.fragment_main, container, false);
marketActivity = new MarketActivity(context);
marketActivity.loadMarkets(rootView);
break;
case 4:
rootView = inflater.inflate(R.layout.fragment_main, container, false);
break;
}
return rootView;
}
我的设置功能在movementActivity中
public void setUp()
{
Intent intent = new Intent("com.google.zxing.client.android.SCAN");
intent.putExtra("com.google.zxing.client.android.SCAN.SCAN_MODE", "QR_CODE_MODE");
startActivityForResult(intent, 0);
}
而onActivityResult也出现在movementActivity中
public void onActivityResult(int requestCode, int resultCode, Intent intent)
{
Log.e("onActivityResult", "1");
if(requestCode == 0) {
if(resultCode == RESULT_OK) {
Log.e("onActivityResult", "3");
String contents = intent.getStringExtra("SCAN_RESULT");
String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
Log.e("onActivityResult", "2");
Log.i("xZing", "contents: "+contents+" format: "
+format);
// Handle successful scan
}
else if(resultCode == RESULT_CANCELED)
{ // Handle cancel
Log.i("xZing", "Cancelled");
}
}
}
问题是当我调用setup函数时,我得到了这个错误
07-13 05:26:32.803 20962-20962/com.baagmn.routingware E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at android.app.Activity.startActivityForResult(Activity.java:3204)
at com.baagmn.routingware.Activities.SettingActivities.MovementActivity.setUp(MovementActivity.java:40)
at com.baagmn.routingware.Activities.MainActivity$PlaceholderFragment.onCreateView(MainActivity.java:164)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:828)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1032)
at android.app.BackStackRecord.run(BackStackRecord.java:622)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1382)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
at dalvik.system.NativeStart.main(Native Method)
抱歉我的英语不好,我希望你能理解我的问题我猜你的设备上没有安装zxing活动 您使用的方法要求同时安装activity和standalone zxing activity。如果你想直接集成,你需要一个更复杂的计划。你可以这么做,但我面前没有这个
不过,通常情况下,我认为错误会比NPE更严重,所以我可能会错。在zxing中使用intents最安全的方法是使用INTENTEGRATOR类-这很好地处理了设备上未安装条形码扫描仪应用程序的情况。要使用它,请在setUp()方法中尝试以下操作:
当设备上不存在
com.google.zxing.client.android.SCAN
时,这应该可以避免NPE。这种方法不可能发生NPE。是否确实显示了编译和部署的内容?否,如果是,则会导致ActivityNotFoundException
。这是另外一回事。我刚做了一些测试。它真的必须是别的东西。
public void setUp() {
IntentIntegrator integrator = new IntentIntegrator(this);
integrator.addExtra("SCAN_MODE", "QR_CODE_MODE");
integrator.initiateScan();
}