感谢对NFC和一些特定内容的回复，我已经理解并设法编译了一个代码，用户可以在其中读取标记，如果标记包含与我的代码类似的字符串，优惠券将被添加（图像更改），整数增加1.此整数将由SharedPreferences保存，用于确定用户已收集的优惠券数量并将其显示在简历上。
然而，在编译之后，当我尝试运行它时，我的应用程序立即停止。有人可以帮我查看我可能出错的地方吗？我知道它有点长，但我真的不知道出了什么问题。
@TargetApi(10)
//I have to use this line of code because I'm targetted to code at API 8 but some NFC functionalities that I use requires API 10.
public class CouponManager extends Activity {
private static final String TAG = "NFCReadTag";
private NfcAdapter mNfcAdapter;
private IntentFilter[] mNdefExchangeFilters;
private PendingIntent mNfcPendingIntent;
public static final String PREF_FILE_NAME = "PrefFile";
private int[] images = new int[10];
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.coupon_layout);
//List of images
images[0]=R.drawable.cp0;
images[1]=R.drawable.cp1;
images[2]=R.drawable.cp2;
images[3]=R.drawable.cp3;
images[4]=R.drawable.cp4;
images[5]=R.drawable.cp5;
images[6]=R.drawable.cp6;
images[7]=R.drawable.cp7;
images[8]=R.drawable.cp8;
images[9]=R.drawable.cp9;
images[10]=R.drawable.cp10;
//Restore preferences
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
int storedPreference = preferences.getInt("storedInt", 0);
//Image to use depending on coupon collected
final ImageView img = new ImageView(this);
if(storedPreference!=10)
{
img.setImageResource(images[storedPreference]);
}
else
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setCancelable(false);
builder.setTitle("Redeem Your Coupon?");
builder.setInverseBackgroundForced(true);
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which)
{
dialog.dismiss();
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", 0); // value to store
editor.commit();
img.setImageResource(images[0]);
}
});
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
img.setImageResource(images[10]);
}
});
}
//Check and send Intent from NFC tag discovered
mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
mNfcPendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP
| Intent.FLAG_ACTIVITY_CLEAR_TOP), 0);
IntentFilter coupontag = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
coupontag.addDataScheme("http");
coupontag.addDataAuthority("www.ichatime.com", null);
coupontag.addDataPath(".*", PatternMatcher.PATTERN_SIMPLE_GLOB);
mNdefExchangeFilters = new IntentFilter[] { coupontag };
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
@Override
protected void onResume() {
super.onResume();
if(mNfcAdapter != null) {
mNfcAdapter.enableForegroundDispatch(this, mNfcPendingIntent,
mNdefExchangeFilters, null);
} else {
Toast.makeText(getApplicationContext(), "Sorry, No NFC Adapter found.", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onPause() {
super.onPause();
if(mNfcAdapter != null) mNfcAdapter.disableForegroundDispatch(this);
}
@Override
protected void onStop() {
super.onStop();
// We need an Editor object to make preference changes.
// All objects are from android.context.Context
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
int storedPreference = preferences.getInt("storedInt", 0);
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", storedPreference); // value to store
editor.commit();
}
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
int storedPreference = preferences.getInt("storedInt", 0);
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(intent.getAction())) {
NdefMessage[] messages = null;
Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
if (rawMsgs != null) {
messages = new NdefMessage[rawMsgs.length];
for (int i = 0; i < rawMsgs.length; i++) {
messages[i] = (NdefMessage) rawMsgs[i];
}
}
if(messages[0] != null) {
String result="";
byte[] payload = messages[0].getRecords()[0].getPayload();
// this assumes that we get back am SOH followed by host/code
for (int b = 1; b<payload.length; b++) { // skip SOH
result += (char) payload[b];
}
if (result == "ichatime.com")
{
final ImageView img = new ImageView(this);
Toast.makeText(getApplicationContext(), "Coupon collected!", Toast.LENGTH_SHORT).show();
if (storedPreference!=10)
{
storedPreference++;
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", storedPreference);
img.setImageResource(images[storedPreference]);
}
if (storedPreference==10)
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setCancelable(false);
builder.setTitle("Redeem Your Coupon?");
builder.setInverseBackgroundForced(true);
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which)
{
dialog.dismiss();
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", 0); // value to store
editor.commit();
img.setImageResource(images[0]);
}
});
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
img.setImageResource(images[10]);
}
});
}
else
{
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", 10);
img.setImageResource(images[10]);
}}
else
{
Toast.makeText(getApplicationContext(), "Wrong tag detected!", Toast.LENGTH_SHORT).show();
}
//Debugging Mode to see what is contained in the tags.
// Toast.makeText(getApplicationContext(), "Tag Contains " + result, Toast.LENGTH_SHORT).show();
}
}
}
}
Logcat错误：
>11-26 01:16:11.869: D/AndroidRuntime(550): Shutting down VM
>
11-26 01:16:11.869: W/dalvikvm(550): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
>
11-26 01:16:11.929: I/dalvikvm(550): threadid=3: reacting to signal 3
>
11-26 01:16:11.979: E/AndroidRuntime(550): FATAL EXCEPTION: main
>
**11-26 01:16:11.979: E/AndroidRuntime(550): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ponpon/com.example.ponpon.MainActivity}: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ponpon/com.example.ponpon.CouponManager}: java.lang.ArrayIndexOutOfBoundsException: length=10; index=10**
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.access$600(ActivityThread.java:123)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.os.Handler.dispatchMessage(Handler.java:99)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.os.Looper.loop(Looper.java:137)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.main(ActivityThread.java:4424)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at java.lang.reflect.Method.invokeNative(Native Method)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at java.lang.reflect.Method.invoke(Method.java:511)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at dalvik.system.NativeStart.main(Native Method)
>
11-26 01:16:11.979: E/AndroidRuntime(550): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ponpon/com.example.ponpon.CouponManager}: java.lang.ArrayIndexOutOfBoundsException: length=10; index=10
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.startActivityNow(ActivityThread.java:1797)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:682)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.widget.TabHost.setCurrentTab(TabHost.java:346)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.widget.TabHost.addTab(TabHost.java:236)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at com.example.ponpon.MainActivity.onCreate(MainActivity.java:37)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.Activity.performCreate(Activity.java:4465)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
>
11-26 01:16:11.979: E/AndroidRuntime(550): ... 11 more
>
11-26 01:16:11.979: E/AndroidRuntime(550): Caused by: java.lang.ArrayIndexOutOfBoundsException: length=10; index=10
>
11-26 01:16:11.979: E/AndroidRuntime(550): at com.example.ponpon.CouponManager.onCreate(CouponManager.java:53)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.Activity.performCreate(Activity.java:4465)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
>
11-26 01:16:11.979: E/AndroidRuntime(550): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
>
11-26 01:16:11.979: E/AndroidRuntime(550): ... 21 more
我的阵列出了什么问题？谢谢你的澄清！
答案 0 :(得分：0)
我似乎通过将数组计数加1来解决问题。我不明白的是，我想在数组中保留11个项目，所以不是
private int [] images = new int [10]够吗？
根据我的理解，int [0]保留第一个值，因此int [10]将保留第11个值？谢谢你们！
答案 1 :(得分：0)
您的logcat正在onCreate方法上打印一个ArrayOutOfBounds异常。
问题是你要声明一个10个项目大小的数组，然后尝试在其上放置11个项目。
你必须声明一个新的int [11]数组。