Android应用程序在单击按钮时崩溃

时间：2016-04-02 12:26:01

标签： android xml onclicklistener android-appcompat android-button

我正在使用按钮从一个活动切换到另一个活动。在同一活动中，浮动操作按钮运行良好，但正常按钮导致异常。我提供按钮相关的java类，xml文件和logcat。

IndexPage.java 

public class IndexPage extends AppCompatActivity {



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_index_page);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

           Intent in = new Intent(IndexPage.this, FoodEntry.class);
            startActivity(in);

        }
    });

    Button b = (Button)findViewById(R.id.buttonBackUp);


        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(IndexPage.this, Form.class);
                startActivity(intent);
            }
        });

  }

}

activity_index_page.xml 

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.praval.healthfreak.IndexPage">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />


</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_index_page" />

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    android:src="@drawable/newfloatnew" />
</android.support.design.widget.CoordinatorLayout>

content_index_page.xml 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.praval.healthfreak.IndexPage"
tools:showIn="@layout/activity_index_page">


<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="New Button"
    android:id="@+id/buttonBackUp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />
</RelativeLayout>

logcat

    04-02 17:54:06.569 24689-24689/com.praval.healthfreak W/dalvikvm: threadid=1: calling UncaughtExceptionHandler
04-02 17:54:06.577 24689-24689/com.praval.healthfreak E/AndroidRuntime: FATAL EXCEPTION: main
                                                                        Process: com.praval.healthfreak, PID: 24689
                                                                        java.lang.RuntimeException: Unable to start activity ComponentInfo{com.praval.healthfreak/com.praval.healthfreak.Form}: java.lang.NumberFormatException: Invalid int: ""
                                                                            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2389)
                                                                            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2441)
                                                                            at android.app.ActivityThread.access$900(ActivityThread.java:151)
                                                                            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354)
                                                                            at android.os.Handler.dispatchMessage(Handler.java:110)
                                                                            at android.os.Looper.loop(Looper.java:193)
                                                                            at android.app.ActivityThread.main(ActivityThread.java:5345)
                                                                            at java.lang.reflect.Method.invokeNative(Native Method)
                                                                            at java.lang.reflect.Method.invoke(Method.java:515)
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
                                                                            at dalvik.system.NativeStart.main(Native Method)
                                                                         Caused by: java.lang.NumberFormatException: Invalid int: ""
                                                                            at java.lang.Integer.invalidInt(Integer.java:137)
                                                                            at java.lang.Integer.parseInt(Integer.java:358)
                                                                            at java.lang.Integer.parseInt(Integer.java:331)
                                                                            at com.praval.healthfreak.Form.onCreate(Form.java:30)
                                                                            at android.app.Activity.performCreate(Activity.java:5343)
                                                                            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1088)
                                                                            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2343)
                                                                            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2441) 
                                                                            at android.app.ActivityThread.access$900(ActivityThread.java:151) 
                                                                            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1354) 
                                                                            at android.os.Handler.dispatchMessage(Handler.java:110) 
                                                                            at android.os.Looper.loop(Looper.java:193) 
                                                                            at android.app.ActivityThread.main(ActivityThread.java:5345) 
                                                                            at java.lang.reflect.Method.invokeNative(Native Method) 
                                                                            at java.lang.reflect.Method.invoke(Method.java:515) 
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828) 
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644) 
                                                                            at     dalvik.system.NativeStart.main(Native Method) 

（编辑）---＆gt; （新版本根据你的所有建议，但我仍然被卡住了）

Form.java 

public class Form extends AppCompatActivity {

String g="m";
int a=0,w=0,f=0,i=0;
double val , bmi;
int cal=0;

TextView tBmi = (TextView)findViewById(R.id.textResult);
TextView tFitOrNot = (TextView)findViewById(R.id.textFitOrNot);
TextView tCalorie = (TextView)findViewById(R.id.textCalorie);

EditText gender = (EditText)findViewById(R.id.editGender);
EditText age = (EditText)findViewById(R.id.editAge);
EditText weight = (EditText)findViewById(R.id.editWeight);
EditText feet = (EditText)findViewById(R.id.editFeet);
EditText inch = (EditText)findViewById(R.id.editInch);

static String s1="underweight";
static String s2="fit";
static String s3="overweight";
static String s4="obese";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_form);

    Button bCalculate = (Button)findViewById(R.id.buttonBMI);
    bCalculate.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            calculation();
        }
    });


}

public void calculation() {

   /* gender.setText("m");
    age.setText("m");
    weight.setText("m");
    feet.setText("m");
    inch.setText("m"); */

    g = gender.getText().toString();
    a = Integer.parseInt(age.getText().toString());
    w = Integer.parseInt(weight.getText().toString());
    f = Integer.parseInt(feet.getText().toString());
    i = Integer.parseInt(inch.getText().toString());
    //feet and inches converted to metre
    val=((f*12)+i)*0.245;
    bmi=w*100/(val*val);

    tBmi.setText(String.valueOf(bmi));

    if (bmi<18.5)
    {
        tFitOrNot.setText(s1);
        if(g.equals("m"))
        {
            if(a>=18 && a<=25)
            {
                cal=3200;
               // tCalorie.setText(s5);
            }
            if(a>25 && a<=40)
            {
                cal=3400;
                //tCalorie.setText(s6);
            }
            if(a>40 && a<=60)
            {
                cal=3400;
              //  tCalorie.setText(s6);
            }


        }
        else
        {
            if(a>=18 && a<=25)
            {
                cal=3100;
                //tCalorie.setText(s7);
            }
            if(a>25 && a<=40)
            {
                cal=2900;
                //tCalorie.setText(s8);
            }
            if(a>40 && a<=60)
            {
                cal=2900;
             //   tCalorie.setText(s8);
            }

        }
    }
    else if(bmi>=18.5 && bmi<=24.9)
    {
        tFitOrNot.setText(s2);
        if(g.equals("m"))
        {
            if(a>=18 && a<=25)
            {
                cal=3000;
               // tCalorie.setText(s9);
            }
            if(a>25 && a<=40)
            {
                cal=2800;
             //   tCalorie.setText(s12);
            }
            if(a>40 && a<=60)
            {
                cal=2700;
               // tCalorie.setText(s10);
            }


        }
        else
        {
            if(a>=18 && a<=25)
            {
                cal=2700;
                //tCalorie.setText(s10);
            }
            if(a>25 && a<=40)
            {
                cal=2400;
                //tCalorie.setText(s14);
            }
            if(a>40 && a<=60)
            {
                cal=2000;
                //tCalorie.setText(s13);
            }

        }
    }
    else if(bmi>=25 && bmi<=29.9)
    {
        tFitOrNot.setText(s3);
        if(g.equals("m"))
        {
            if(a>=18 && a<=25)
            {
                cal=2200;
                //tCalorie.setText(s11);
            }
            if(a>25 && a<=40)
            {
                cal=2200;
               // tCalorie.setText(s11);
            }
            if(a>40 && a<=60)
            {
                cal=1200;
                //tCalorie.setText(s16);
            }


        }
        else
        {
            if(a>=18 && a<=25)
            {
                cal=1200;
                //tCalorie.setText(s16);
            }
            if(a>25 && a<=40)
            {
                cal=1500;
               // tCalorie.setText(s15);
            }
            if(a>40 && a<=60)
            {
                cal= 1300;
               // tCalorie.setText(s19);
            }

        }
    }
    else
    {
        tFitOrNot.setText(s4);
        if(g.equals("m"))
        {
            if(a>=18 && a<=25)
            {
                cal=2000;
                //tCalorie.setText(s13);
            }
            if(a>25 && a<=40)
            {
                cal=2500;
                //tCalorie.setText(s18);
            }
            if(a>40 && a<=60)
            {
                cal=2050;
                //tCalorie.setText(s17);
            }


        }
        else
        {
            if(a>=18 && a<=25)
            {
                cal=1000;
                //tCalorie.setText(s20);
            }
            if(a>25 && a<=40)
            {
                cal=1300;
                //tCalorie.setText(s19);
            }
            if(a>40 && a<=60)
            {
                cal=1200;
                //tCalorie.setText(s16);
            }

        }
    }
    tCalorie.setText(String.valueOf(cal));
}
}

编辑 - ＆gt;在editText中输入值 Screenshot

3 个答案:

答案 0 :(得分：1)

您正在通过""获取Integer个对象。这导致exception。

下面：

a = Integer.parseInt(age.getText().toString());
w = Integer.parseInt(weight.getText().toString());
f = Integer.parseInt(feet.getText().toString());
i = Integer.parseInt(inch.getText().toString());

将您的计算结果排除在onCreate之外，因为如果您未向EditText设置任何内容，则会始终抛出exception。例如，您可以将这些按钮单击。

尝试将解析放在try catch块中以防止Run time exceptions。

例如：

try{
  a = Integer.parseInt(age.getText().toString());
  // similarly others.
}catch(NumberFormatException e){

}

答案 1 :(得分：1)

a = Integer.parseInt(age.getText().toString()); 
w = Integer.parseInt(weight.getText().toString()); 
f = Integer.parseInt(feet.getText().toString()); 
i = Integer.parseInt(inch.getText().toString());

将这些线条移动到按钮单击或其他内容中。因为当您的活动运行时，您的edittexts为空并返回＆＃34; ＆＃34;当你写age.getText().toString()时。那＆＃34; ＆＃34;被传递给生成错误的Integer.parseInt()函数。在调用Integer.parseInt()函数

之前，请确保您的edittexts不为空

答案 2 :(得分：0)

当您启动表单活动时，您的应用程序崩溃，因为您的所有EditTexts都为空，而您的代码实际上会在此处引发错误

Integer.parseInt("");

要解决此问题，您可能应该向表单布局XML添加一个按钮，并将计算值的大部分代码移动到onClick方法中。

我还建议将逻辑分解为某些方法，而不是将所有内容都放在onCreate中，因为那些if语句看起来像很多重复的代码

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