Question

我有edittext。如果编辑文本不为空，如代码所示，一切正常。但是，如果edittext为空，则按下按钮时应用程序会崩溃。似乎else{}块不能按预期工作。我尝试过许多其他方法来查看edittext是否为空，例如contains()，长度（）> 0等等。

b.setOnClickListener(new OnClickListener(){
        public void onClick(View v){

//////////////////////////////////// Row 1 Start /////////////////////////////
        String credit1s = credit1.getText().toString();

        if (!TextUtils.isEmpty(credit1s)) {
        // call parseDouble in here
        double credit_1 = Double.parseDouble(credit1s);
        double CE1 = 0;
            if(grade1.getText().toString().toUpperCase().equals("A")) 
                CE1 = 4.0*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals("B+")) 
                CE1 = 3.5*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals("B")) 
                CE1 = 3.0*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals("C+")) 
                CE1 = 2.5*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals("C")) 
                CE1 = 2.0*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals("D")) 
                CE1 = 1.0*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals("F")) 
                CE1 = 0.0*credit_1;
            else if(grade1.getText().toString().toUpperCase().equals(""))
                CE1 = 0;
            ce.setText(Double.toString(CE1));
        }


 else{
            double CE1;
            CE1=0;
                    ce.setText(Double.toString(CE1));
        }

logcat的：

07-26 19:21:18.640: W/asset(11731): Copying FileAsset 0x779b8390 (zip:/data/app/com.example.rutgersgpacalculator-2.apk:/resources.arsc) to buffer size 108076 to make it aligned.
07-26 19:21:18.950: I/Adreno-EGL(11731): <qeglDrvAPI_eglInitialize:385>: EGL 1.4 QUALCOMM build: AU_LINUX_ANDROID_KK_3.5_RB1.04.04.02.006.066_msm8974_refs/tags/AU_LINUX_ANDROID_KK_3.5_RB1.04.04.02.006.066__release_AU ()
07-26 19:21:18.950: I/Adreno-EGL(11731): OpenGL ES Shader Compiler Version: E031.24.00.06
07-26 19:21:18.950: I/Adreno-EGL(11731): Build Date: 02/06/14 Thu
07-26 19:21:18.950: I/Adreno-EGL(11731): Local Branch: 
07-26 19:21:18.950: I/Adreno-EGL(11731): Remote Branch: refs/tags/AU_LINUX_ANDROID_KK_3.5_RB1.04.04.02.006.066
07-26 19:21:18.950: I/Adreno-EGL(11731): Local Patches: NONE
07-26 19:21:18.950: I/Adreno-EGL(11731): Reconstruct Branch: NOTHING
07-26 19:21:19.030: I/InputMethodManager(11731): [startInputInner] EditorInfo { packageName=com.example.rutgersgpacalculator, inputType=0x20001, imeOptions=0x48000005, privateImeOptions=null }, windowGainingFocus=android.view.ViewRootImpl$W@41ae1e58, mServedView=android.widget.EditText{41a8e9b8 VFED..CL .F....ID 0,193-270,311 #7f05003f app:id/Course1}
07-26 19:21:23.740: I/InputMethodManager(11731): [startInputInner] EditorInfo { packageName=com.example.rutgersgpacalculator, inputType=0x2002, imeOptions=0x8004005, privateImeOptions=null }, windowGainingFocus=null, mServedView=android.widget.EditText{41aa6d78 VFED..CL .F.P..ID 270,193-420,311 #7f050046 app:id/editText7}
07-26 19:21:26.580: I/InputMethodManager(11731): [startInputInner] EditorInfo { packageName=com.example.rutgersgpacalculator, inputType=0x20001, imeOptions=0x48000005, privateImeOptions=null }, windowGainingFocus=null, mServedView=android.widget.EditText{41a9e298 VFED..CL .F.P..ID 451,193-594,311 #7f05004b app:id/editText13}
07-26 19:21:28.600: W/dalvikvm(11731): threadid=1: thread exiting with uncaught exception (group=0x41624e18)
07-26 19:21:28.610: E/AndroidRuntime(11731): FATAL EXCEPTION: main
07-26 19:21:28.610: E/AndroidRuntime(11731): Process: com.example.rutgersgpacalculator, PID: 11731
07-26 19:21:28.610: E/AndroidRuntime(11731): java.lang.NumberFormatException: Invalid double: ""
07-26 19:21:28.610: E/AndroidRuntime(11731):    at java.lang.StringToReal.invalidReal(StringToReal.java:63)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at java.lang.StringToReal.parseDouble(StringToReal.java:248)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at java.lang.Double.parseDouble(Double.java:295)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at com.example.rutgersgpacalculator.MainActivity$1.onClick(MainActivity.java:423)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at android.view.View.performClick(View.java:4480)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at android.view.View$PerformClick.run(View.java:18686)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at android.os.Handler.handleCallback(Handler.java:733)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at android.os.Handler.dispatchMessage(Handler.java:95)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at android.os.Looper.loop(Looper.java:157)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at android.app.ActivityThread.main(ActivityThread.java:5872)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at java.lang.reflect.Method.invokeNative(Native Method)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at java.lang.reflect.Method.invoke(Method.java:515)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:852)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:668)
07-26 19:21:28.610: E/AndroidRuntime(11731):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

听起来像credit1，EditText对象或getText（）返回的CharSequence为null。没有Logcat帖子，我无法确定哪个。

首先应该确保credit1s不为null，而且credit1s.getText（）也不是：

String credit1s = "";

if (credit1 != null && credit1.getText() != null) {
    credit1s = credit1.getText().toString();
}

if (!TextUtils.isEmpty(credit1s)) {

....

Answer 2

您可以通过此代码

简单地检查edittext的长度

 EditText ed = (EditText) findViewById(R.id.age);

String ed_text = ed.getText().toString().trim();

if(ed_text.isEmpty() || ed_text.length() == 0 || ed_text.equals("") || ed_text == null)
{
    //EditText is empty
}
else
{
    //EditText is not empty
}

或简单地通过

if(ed_text.length()>0){
// EMPTY
}else{
//NOT EMPTY
}

如果edittext为空，如何读取

2 个答案: