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首先,我只想说,stackoverflow 社区至少可以这么说。尝试构建我的前两个应用程序,目前已部署但试图在非洲淘汰几个课程。

所以,我正在制作一个非常基本的蛋白质跟踪应用程序。原谅我过多的评论,当我试图弄清楚这些东西时,它让我保持头脑清醒。

我已经查找并找到了很多以前问题的答案,但我不知道如何在这方面取得进展。

如何在 Android 中计算 EditText 值?

我从那个开始,它很棒(谢谢你 luvieere),但我认为我制作的可编辑部分有点吓人。我在 Eclipse 中的 logcat 正在调用该行以及我的计算方法。

这可能只是一些简单的事情,但据我所见,这是一个如此广泛的错误,你只需要查看这些可怕的代码行就可以知道我哪里出错了。再次感谢人们的帮助,这是我第一次提出问题,所以让我知道如何给你疯狂的代表。:D

一些代码:

public class anitasProteinTracker extends Activity implements OnClickListener {
    Button btnOverviewSnapshot, btnNomNoms, btnSettingsCalculate;
    EditText etSettingsProteinGoal, etWeight;

    <//random code here//>

    btnSettingsCalculate = (Button) findViewById(R.id.btnSettingsCalculate);
    btnSettingsCalculate.setOnClickListener(this);

    <//random code here//>

public void onClick(View v) {

    switch(v.getId()){

    <//random code here//>

    case R.id.btnSettingsCalculate:

        //clicking this will find the value and set it to the goal edittext
        calcProteinGoal();   <---This line showed up in logcat

        break;

    }
}

private void calcProteinGoal() {
    // TODO Auto-generated method stub
    Editable etWeightlbs;    <----this is the other error line in logcat
    double weightlbs = 0;
    double weightkgs = 0;
    double proteinMultiplier;
    double gProtein = 0;

    //get the weight from the user and ensure it's a number
    etWeightlbs = etWeight.getText();

        if (etWeightlbs != null)
            weightlbs = Double.parseDouble(etWeightlbs.toString());
            //convert lbs -> kgs
            weightkgs = weightlbs / 2.2;

    //get spinner value
    //don't know how to do that yet, going to set the variable
    proteinMultiplier = 0.8;

    //set up protein goal   
    gProtein = weightkgs * proteinMultiplier;

    etSettingsProteinGoal.setText(String.valueOf(gProtein));

一些logcat:

07-03 21:41:14.405: W/dalvikvm(1861): threadid=1: thread exiting with uncaught exception (group=0x4001d7e0)
07-03 21:41:14.429: E/AndroidRuntime(1861): FATAL EXCEPTION: main
07-03 21:41:14.429: E/AndroidRuntime(1861): java.lang.NullPointerException
07-03 21:41:14.429: E/AndroidRuntime(1861):     at com.joemac.anitasprotein.anitasProteinTracker.calcProteinGoal(anitasProteinTracker.java:119)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at com.joemac.anitasprotein.anitasProteinTracker.onClick(anitasProteinTracker.java:102)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at android.view.View.performClick(View.java:2408)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at android.view.View$PerformClick.run(View.java:8816)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at android.os.Handler.handleCallback(Handler.java:587)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at android.os.Handler.dispatchMessage(Handler.java:92)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at android.os.Looper.loop(Looper.java:123)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at android.app.ActivityThread.main(ActivityThread.java:4627)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at java.lang.reflect.Method.invokeNative(Native Method)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at java.lang.reflect.Method.invoke(Method.java:521)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
07-03 21:41:14.429: E/AndroidRuntime(1861):     at dalvik.system.NativeStart.main(Native Method)
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1 回答 1

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只是因为我在那里看不到它......你也在为 EditText 做 findViewById 对吗?我所看到的只是按钮的绑定。

于 2012-07-03T19:44:05.043 回答