public class MainActivity extends AppCompatActivity {
public void grade (View view){
final EditText varEditBox = (EditText)findViewById(R.id.editBox);
TextView varText = (TextView) findViewById(R.id.textView);
Button button = (Button) findViewById(R.id.button);
if (varEditBox.getText().toString().isEmpty()){
Toast.makeText(getApplicationContext(), "EMPTY", Toast.LENGTH_SHORT).show();
varText.setText( "");
}
if ((Integer.parseInt(varEditBox.getText().toString() )>=101)||(Integer.parseInt(varEditBox.getText().toString() )<1) ){
Toast.makeText(getApplicationContext(), "Invalid", Toast.LENGTH_SHORT).show();
varText.setText( "");
} }
我有上面的代码，条件是检查EditText框是否为空，但是当我按下带有空EditBox的按钮时，应用程序崩溃了。我一直在调试但没有成功。通常情况下，当我不进行检查时，我会收到此错误，现在我已经完成了检查，它仍然在这里。另外varEditBox也不是空的，因为另一个if语句也是运行的。如果我输入一个超过100的数字，它就会出现问题＆＃34;无效＆＃34;因此，第二个条件起作用
LogCat错误。我不确定是否必须发布所有内容，但这是我得到的错误
FATAL EXCEPTION: main
Process: com.listener.gradesystem, PID: 31936
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5156)
at android.view.View$PerformClick.run(View.java:20755)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5835)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5156)
at android.view.View$PerformClick.run(View.java:20755)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5835)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
Caused by: java.lang.NumberFormatException: Invalid int: ""
at java.lang.Integer.invalidInt(Integer.java:138)
at java.lang.Integer.parseInt(Integer.java:358)
at java.lang.Integer.parseInt(Integer.java:334)
at com.listener.gradesystem.MainActivity.grade(MainActivity.java:24)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5156)
at android.view.View$PerformClick.run(View.java:20755)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5835)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
答案 0 :(得分：1)
Caused by: java.lang.NumberFormatException: Invalid int: ""
你们中的一个Integer.parseInt来电失败了。我只能假设你的字符串中有空格。如果您的EditText仅允许不仅仅是数字，请考虑这样做：
public void grade (View view){
final EditText varEditBox = (EditText)findViewById(R.id.editBox);
TextView varText = (TextView) findViewById(R.id.textView);
Button button = (Button) findViewById(R.id.button);
// trim to remove whitespace
final String text = varEditBox.getText().toString().trim();
if (TextUtils.isEmpty(text) || !TextUtils.isDigitsOnly(text)){
Toast.makeText(getApplicationContext(), "EMPTY OR NOT NUMERIC", Toast.LENGTH_SHORT).show();
varText.setText("");
// quit early, don't need to parse this number
return;
}
// we should have already quit by now if we can't parse this number
int value = Integer.parseInt(text);
if (value >= 101 || value < 1) {
Toast.makeText(getApplicationContext(), "Invalid", Toast.LENGTH_SHORT).show();
varText.setText("");
}
}
如果仍然失败，至少会突出显示问题所在。
答案 1 :(得分：0)
final EditText varEditBox = (EditText)findViewById(R.id.editBox);
TextView varText = (TextView) findViewById(R.id.textView);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (varEditBox.getText().toString().trim().isEmpty()){
Toast.makeText(getApplicationContext(), "EMPTY", Toast.LENGTH_SHORT).show();
varText.setText( "");
}
else{
if ((Integer.parseInt(varEditBox.getText().toString())>=101)||(Integer.parseInt(varEditBox.getText().toString() )<1) ){
Toast.makeText(getApplicationContext(), "Invalid", Toast.LENGTH_SHORT).show();
varText.setText( "");
}
}
}
});