Java 为什么我的文本视图不显示任何内容?
我现在正在做一个有条形码扫描仪的应用程序。目前,当我扫描条形码时,它会显示条形码的格式和内容。但目前它没有显示扫描后的格式和内容 这是密码Java 为什么我的文本视图不显示任何内容?,java,android,barcode,zxing,barcode-scanner,Java,Android,Barcode,Zxing,Barcode Scanner,我现在正在做一个有条形码扫描仪的应用程序。目前,当我扫描条形码时,它会显示条形码的格式和内容。但目前它没有显示扫描后的格式和内容 这是密码 public class ThreeFragment extends Fragment{ public ThreeFragment() { // Required empty public constructor } Button scan_btn; EditText Edit_current; T
public class ThreeFragment extends Fragment{
public ThreeFragment() {
// Required empty public constructor
}
Button scan_btn;
EditText Edit_current;
TextView formatTxt, contentTxt;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_one, container, false);
scan_btn = (Button) view.findViewById(R.id.scan_button);
final Activity activity = getActivity();
scan_btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
IntentIntegrator integrator = new IntentIntegrator(activity);
integrator.setDesiredBarcodeFormats(IntentIntegrator.PRODUCT_CODE_TYPES);
integrator.setPrompt("Scan");
integrator.setCameraId(0);
integrator.setBeepEnabled(false);
integrator.setBarcodeImageEnabled(true);
integrator.initiateScan();
}
});
return view;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
if (result.getContents() != null) {
if (result.getContents() != null){
String scanContent = result.getContents();
String scanFormat = result.getFormatName();
// display it on screen
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
} else {
Toast toast = Toast.makeText(getContext(),"No scan data received!", Toast.LENGTH_SHORT);
toast.show();
}
}
}
}
我的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" >
<Button android:id="@+id/scan_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="@string/scan" />
<TextView
android:id="@+id/scanFormat"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/scan_button" />
<TextView
android:id="@+id/scanContent"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textIsSelectable="true"
android:layout_centerHorizontal="true"
android:layout_below="@id/scanFormat" />
</RelativeLayout>
仍然无法显示格式和内容您的代码至少有两个问题: 您有两次相同的if语句:
if (result.getContents() != null) {
if (result.getContents() != null){
外部的没有else,所以即使内部的有else,你也不知道条件何时失败
formatTxt未初始化。您需要在onCreateView中的某个位置添加对findViewById的调用来初始化它
在onCreateView方法中初始化formatTxt和contentTxt! 扫描是正常的,它只是给NPE,因为没有初始化TextView 在你的活动结果中
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
if (result.getContents() != null) {
String scanContent = result.getContents();
String scanFormat = result.getFormatName();
// display it on screen
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
}
}
更新:这就是它在代码中的外观
public class ThreeFragment extends Fragment{
public ThreeFragment() {
// Required empty public constructor
}
Button scan_btn;
EditText Edit_current;
TextView formatTxt, contentTxt;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_one, container, false);
scan_btn = (Button) view.findViewById(R.id.scan_button);
//initialize the textViews
formatTxt = (TextView) view.findViewById(R.id.scanFormat);
contentTxt = (TextView) view.findViewById(R.id.scanContent);
final Activity activity = getActivity();
scan_btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
IntentIntegrator integrator = new IntentIntegrator(activity);
integrator.setDesiredBarcodeFormats(IntentIntegrator.PRODUCT_CODE_TYPES);
integrator.setPrompt("Scan");
integrator.setCameraId(0);
integrator.setBeepEnabled(false);
integrator.setBarcodeImageEnabled(true);
integrator.initiateScan();
}
});
return view;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
if (result.getContents() != null) {
String scanContent = result.getContents();
String scanFormat = result.getFormatName();
// display it on screen
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
}else {
Toast toast = Toast.makeText(getContext(),"No scan data received!", Toast.LENGTH_SHORT);
toast.show();
}
}
}
这是我的主要活动,但我看不到初始化formatTxt的地方有任何错误如果您可能删除外部冗余的If result.getContents!=无效的{语句,您将能够看到失败吐司。我已更改代码to@jason我已经更新了我的答案,看一看!在我的设备上进行了测试。它的工作原理我使用了你的代码,但仍然没有显示。已经调试了这些行,但它们没有被调用。他们我正在尝试理解你给出的解决方案,但我仍然不理解。可以吗d您提供了一个示例代码,因为我是android studio的新手,正在努力学习。我真的很抱歉,我已经在您的代码中包含了我的解决方案。看看更新。您不了解哪一部分?哦,好吧,现在我明白了,我对在哪里取消文本视图感到困惑。我已经用您的代码编辑了代码,但仍然不会显示在formatTxt.setText;处设置调试指针,并检查是否正在获取值,以及是否调用了onActivityResult..。已调试这些值,但未调用它们out@sadiq这是我的主要活动可以帮助和看一下它的成本,我没有看到任何错误,谢谢
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
if (result.getContents() != null) {
String scanContent = result.getContents();
String scanFormat = result.getFormatName();
// display it on screen
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
}
}
public class ThreeFragment extends Fragment{
public ThreeFragment() {
// Required empty public constructor
}
Button scan_btn;
EditText Edit_current;
TextView formatTxt, contentTxt;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_one, container, false);
scan_btn = (Button) view.findViewById(R.id.scan_button);
//initialize the textViews
formatTxt = (TextView) view.findViewById(R.id.scanFormat);
contentTxt = (TextView) view.findViewById(R.id.scanContent);
final Activity activity = getActivity();
scan_btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
IntentIntegrator integrator = new IntentIntegrator(activity);
integrator.setDesiredBarcodeFormats(IntentIntegrator.PRODUCT_CODE_TYPES);
integrator.setPrompt("Scan");
integrator.setCameraId(0);
integrator.setBeepEnabled(false);
integrator.setBarcodeImageEnabled(true);
integrator.initiateScan();
}
});
return view;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
if (result.getContents() != null) {
String scanContent = result.getContents();
String scanFormat = result.getFormatName();
// display it on screen
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
}else {
Toast toast = Toast.makeText(getContext(),"No scan data received!", Toast.LENGTH_SHORT);
toast.show();
}
}
}
package com.sp.ez_mart_xy;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new OneFragment(), "NAVIGATION");
adapter.addFragment(new TwoFragment(), "HOME");
adapter.addFragment(new ThreeFragment(), "PRICE-CHECKER");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}