if語句做不對的事在我的代碼

-1

public void register(View view) { 

    EditText user = (EditText) findViewById(R.id.registerEditText); 

    if("USER01".equals(user.getText().toString()) || "USER02".equals(user.getText().toString())) { 

     Toast.makeText(RegisterActivity.this,"Correct username!", Toast.LENGTH_SHORT).show(); 
    }else{ 
     Toast.makeText(RegisterActivity.this, "Only USER01 and USER02 is allowed for username!", Toast.LENGTH_SHORT).show(); 
    } 

}

，這裏是我的XML佈局：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:gravity="center" 
android:background="@drawable/green_bg" 
android:orientation="vertical" > 

<TextView 
    android:id="@+id/textView1" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/first" 
    android:textSize="32sp" 
    android:shadowColor="#F70000" 
    android:shadowDx="2.5" 
    android:shadowDy="2.5" 
    android:textColor="#FFFDFD" 
    android:textAppearance="?android:attr/textAppearanceLarge" /> 

<EditText 
    android:id="@+id/registerEditText" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:singleLine="true" 
    android:textColor="#DDFED1" 
    android:hint="@string/user" 
    android:inputType="text|textCapCharacters" > 
</EditText> 

<Button 
    android:id="@+id/button1" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:onClick="register" 
    android:text="@string/register" />

這裏是什麼點擊按鈕後顯示在我的LogCat中：

02-07 11:10:47.155: E/AndroidRuntime(556): FATAL EXCEPTION: main 
02-07 11:10:47.155: E/AndroidRuntime(556): java.lang.IllegalStateException: Could not execute method of the activity 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.view.View$1.onClick(View.java:3039) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.view.View.performClick(View.java:3480) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.view.View$PerformClick.run(View.java:13983) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.os.Handler.handleCallback(Handler.java:605) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.os.Handler.dispatchMessage(Handler.java:92) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.os.Looper.loop(Looper.java:137) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.app.ActivityThread.main(ActivityThread.java:4340) 
02-07 11:10:47.155: E/AndroidRuntime(556): at java.lang.reflect.Method.invokeNative(Native Method) 
02-07 11:10:47.155: E/AndroidRuntime(556): at java.lang.reflect.Method.invoke(Method.java:511) 
02-07 11:10:47.155: E/AndroidRuntime(556): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
02-07 11:10:47.155: E/AndroidRuntime(556): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
02-07 11:10:47.155: E/AndroidRuntime(556): at dalvik.system.NativeStart.main(Native Method) 
02-07 11:10:47.155: E/AndroidRuntime(556): Caused by: java.lang.reflect.InvocationTargetException 
02-07 11:10:47.155: E/AndroidRuntime(556): at java.lang.reflect.Method.invokeNative(Native Method) 
02-07 11:10:47.155: E/AndroidRuntime(556): at java.lang.reflect.Method.invoke(Method.java:511) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.view.View$1.onClick(View.java:3034) 
02-07 11:10:47.155: E/AndroidRuntime(556): ... 11 more 
02-07 11:10:47.155: E/AndroidRuntime(556): Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.database.AbstractCursor.checkPosition(AbstractCursor.java:434) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136) 
02-07 11:10:47.155: E/AndroidRuntime(556): at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50) 
02-07 11:10:47.155: E/AndroidRuntime(556): at tsu.ccs.capstone.RegisterActivity.retrieveNumber(RegisterActivity.java:38) 
02-07 11:10:47.155: E/AndroidRuntime(556): at tsu.ccs.capstone.RegisterActivity.register(RegisterActivity.java:46) 
02-07 11:10:47.155: E/AndroidRuntime(556): ... 14 more

這是一個簡單的測試儀，我已經想出來檢查我的IF statement是否正常工作。但不幸的是，每當我點擊register按鈕，我的應用程序總是強制關閉。有沒有解決方案？

來源

2013-02-06 Erwin Macale

如果您的應用程序強制關閉，有可能寫入日誌異常。看看日誌，找出發生了什麼問題。 –

任何logcat痕跡？ – dumbfingers

我點擊我的按鈕後添加了我的logcat。謝謝！ –

試試這個

if(user.getText().toString().equals ("USER01")|| user.getText().toString().equals ("USER02")) { 
    //do your action 
}else{ 
//do your action  
}

來源

2013-02-07 04:35:38 edwin

我也試過，它也強制關閉。此外，我也發現條件'If（user.length（）> 0）'，它也強制關閉。 –

您必須使用user.getText（）。toString（）。length> 0 – edwin

if語句做不對的事在我的代碼

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