[英]Why am I getting a nullpointerexception (Android)?
I have absolutely no idea why I am getting a nullpointerexception here because almost this same exact code worked in a different program.我完全不知道为什么我在这里得到一个空指针异常,因为几乎完全相同的代码在不同的程序中工作。 I hope it's something simple.
我希望这是简单的事情。
Here is the logcat:这是日志:
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): java.lang.NullPointerException
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at com.prattia.webs.cheaterphysics.Vectors.storeInfo(Vectors.java:216)
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at com.prattia.webs.cheaterphysics.Vectors$2.onClick(Vectors.java:67)
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at android.view.View.performClick(View.java:2465)
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at android.view.View$PerformClick.run(View.java:8907)
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at android.os.Handler.handleCallback(Handler.java:587)
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at android.os.Handler.dispatchMessage(Handler.java:92)
04-09 08:18:57.903: ERROR/AndroidRuntime(14378): at android.os.Looper.loop(Looper.java:123)
Counter is as int initialized at 0 that keeps track of how many times next has been clicked in order to store vAnd here is part of the code with lines 67 and 216 marked:计数器作为 int 初始化为 0,它跟踪 next 被点击的次数以存储 v 这里是代码的一部分,第 67 行和 216 行被标记:
next.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
error.setText("");
if(value.toString().length()==0||angle.toString().length()==0)
error.setText("Must enter both value and angle");
else{
storeInfo(); //67
counter++;
}
}
});
public void storeInfo(){
Doublify(value);
Doublify(angle);
//216 info[counter].value = Double.parseDouble(value.getText().toString());
info[counter].angle = Double.parseDouble(angle.getText().toString());
info[counter].radian = rad.isChecked();
if(q1.isChecked())
info[counter].quad=1;
if(q2.isChecked())
info[counter].quad=2;
if(q3.isChecked())
info[counter].quad=3;
if(q4.isChecked())
info[counter].quad=4;
angle.setText("");
value.setText("");
}
On line 64 you use toString
on the 'value' object which is likely to return the default implementation of the TextView toString()
and probably not a 0 length在第 64 行,您在“值”object 上使用
toString
,它可能会返回 TextView toString()
的默认实现并且可能不是 0 长度
value.toString()
but on line 216 you use the correct way to get the text value, and since you didn't test for it it is possible to be null:但是在第 216 行,您使用了正确的方法来获取文本值,并且由于您没有对其进行测试,因此可能是 null:
value.getText().toString()
Change on line 64 to something like this:将第 64 行更改为如下内容:
if(value.getText() == null || value.getText().toString().length() == 0)
(and similar for the angle
value ) (和
angle
值类似)
If JScoobyCed answer isnt the null pointer, then it might be the array.如果 JScoobyCed 答案不是 null 指针,那么它可能是数组。
info[counter].value // might be null because array's start at 0 not 1
maybe you want:也许你想要:
info[counter - 1].value
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