我的带有标签的滑动视图的 Android 计算器应用程序崩溃了
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【中文标题】我的带有标签的滑动视图的 Android 计算器应用程序崩溃了【英文标题】：My Android Calculator app with swipe view with tabs is crashing 【发布时间】：2016-09-10 17:24:11 【问题描述】：我创建了两个简单的计算器应用程序，它们运行良好。我想将该代码放入一个新应用程序（带有 3 个选项卡的滑动视图）每个选项卡中的每个应用程序代码。该应用程序在三个选项卡中以我想要的方式安装、打开和显示。我在每个选项卡中有两个按钮。清除和计算。当我单击这些按钮（与 ONCLICK 事件连接到 java 代码进行计算）时，应用程序崩溃了。相同的代码在我之前创建的两个不同的应用程序中运行良好，android studio 在我的 java 代码中也没有显示任何错误。
//mainAcitvity.java 代码
package com.example.siv.mahalaxmipetroleums;
import android.support.design.widget.TabLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity
/**
* The @link android.support.v4.view.PagerAdapter that will provide
* fragments for each of the sections. We use a
* @link FragmentPagerAdapter derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* @link android.support.v4.app.FragmentStatePagerAdapter.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The @link ViewPager that will host the section contents.
*/
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
@Override
public boolean onCreateOptionsMenu(Menu menu)
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
@Override
public boolean onOptionsItemSelected(MenuItem item)
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings)
return true;
return super.onOptionsItemSelected(item);
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment()
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber)
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
/* @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View rootView = inflater.inflate(R.layout.fragment_one, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
*/
/**
* A @link FragmentPagerAdapter that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter
public SectionsPagerAdapter(FragmentManager fm)
super(fm);
@Override
public Fragment getItem(int position)
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
if (position == 0)
return new DipToVol();
else if (position == 1)
return new VolToDip();
else if (position ==2)
return new Temp_Density();
else
return PlaceholderFragment.newInstance(position + 1);
@Override
public int getCount()
// Show 3 total pages.
return 3;
@Override
public CharSequence getPageTitle(int position)
switch (position)
case 0:
return "Dip-Vol";
case 1:
return "Vol-Dip";
case 2:
return "Temp-Dens";
return null;
//标签0（第一个标签）的代码
package com.example.siv.mahalaxmipetroleums;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.TextView;
public class DipToVol extends Fragment
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View view = inflater.inflate(R.layout.fragment_one, container, false);
return view;
public double calVol(short rad, short len, int height)
double area;
area = (Math.PI * Math.pow(rad, 2) / 2) - Math.pow(rad, 2) * Math.asin(1 - (height / (double)rad)) - (rad - height) * Math.sqrt(height * (2 * rad - height));
return area*len*0.000001;
public void clickFun1 (View view)
int dipHSD = 0, dipMS = 0;
final short radHSD = 1219;
final short lenHSD = 6810;
final short radMS = 999;
final short lenMS = 6804;
double volHSD, volMS,volHSD1, volMS1;
EditText dipH = (EditText) view.findViewById(R.id.dipHSD1);
EditText dipM = (EditText) view.findViewById(R.id.dipMS1);
TextView volH = (TextView) view.findViewById(R.id.volHSD1);
TextView volM = (TextView) view.findViewById(R.id.volMS1);
try
dipHSD = Integer.parseInt(dipH.getText().toString());
volHSD = calVol(radHSD, lenHSD, dipHSD);
volHSD1 = Math.round(volHSD);
volH.setText(volHSD1 + "");
catch (NumberFormatException e)
volH.setText("");
try dipMS = Integer.parseInt(dipM.getText().toString());
volMS = calVol(radMS, lenMS, dipMS);
volMS1 = Math.round(volMS);
volM.setText(volMS1 + "");
catch(NumberFormatException e)volM.setText("");
public void clearFun1(View view)
EditText dipH = (EditText) view.findViewById(R.id.dipHSD1);
EditText dipM = (EditText) view.findViewById(R.id.dipMS1);
TextView volH = (TextView) view.findViewById(R.id.volHSD1);
TextView volM = (TextView) view.findViewById(R.id.volMS1);
volH.setText("");
volM.setText("");
dipH.setText("");
dipM.setText("");
//标签1（第二个标签）的代码
package com.example.siv.mahalaxmipetroleums;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.TextView;
public class VolToDip extends Fragment
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View view = inflater.inflate(R.layout.fragment_two, container, false);
return view;
private class Liquid_Height
//final double radHSD = 121.9;
//final double lenHSD = 681.0;
//final double radMS = 99.9;
//final double lenMS = 680.4;
final double epsilon = 0.0001;
double dip,volume,radius,length;
// Inner Class
public Liquid_Height(double x, double y, double z)
radius = x;
length = y;
volume = z;
double ratio,guess,dip1;
ratio = this.volume*1000/(radius*radius*length);
guess = 2*ratio/Math.PI;
dip1 = height(guess,ratio,epsilon);
dip = dip1*radius;
public double fun1(double x,double y)
//here x is our guess or result which we try to improve upon, and y is ratio = V/R*R*L
return Math.acos(1-x) + Math.sqrt(x*(2-x))*(x-1) - y ;
public double fun2(double x)
//here x is our guess or or result which we try to improve upon.
return 2*Math.sqrt(x*(2-x));
public boolean isGoodEnough(double x,double y,double e)
//here x is our guess or result which we try to improve upon, and y is ratio = V/R*R*L and e is epsilon
return Math.abs((Math.acos (1-x) + Math.sqrt(x*(2-x))*(x-1) - y)/y)> e;
public double height(double a,double b,double c)
//here a is our guess or result which we try to improve upon, and b is ratio = V/R*R*L and c is epsilon
while (isGoodEnough(a,b,c))
a = a - fun1(a,b)/fun2(a);
return a;
public double getDip()return dip;
//Inner class ends here
public void clickFun2 (View view)
EditText volH = (EditText) view.findViewById(R.id.volHSD2);
EditText volM = (EditText) view.findViewById(R.id.volMS2);
TextView dipH = (TextView) view.findViewById(R.id.dipHSD2);
TextView dipM = (TextView) view.findViewById(R.id.dipMS2);
double volHSD = 0, volMS = 0;
final double radHSD = 121.9;
final double lenHSD = 681.0;
final double radMS = 99.9;
final double lenMS = 680.4;
double dipHSD, dipMS;
try
volHSD = Double.parseDouble(volH.getText().toString());
Liquid_Height HSD = new Liquid_Height(radHSD,lenHSD,volHSD);
dipHSD = Math.round(HSD.getDip()*10.0)/10.0;
dipH.setText(dipHSD + "");
catch (NumberFormatException e)
dipH.setText("");
try volMS = Double.parseDouble(volM.getText().toString());
Liquid_Height MS = new Liquid_Height(radMS,lenMS,volMS);
dipMS = Math.round(MS.getDip()*10.0)/10.0;
dipM.setText(dipMS + "");
catch(NumberFormatException e)
dipM.setText("");
public void clearFun2(View view)
EditText volH = (EditText) view.findViewById(R.id.volHSD2);
EditText volM = (EditText) view.findViewById(R.id.volMS2);
TextView dipH = (TextView) view.findViewById(R.id.dipHSD2);
TextView dipM = (TextView) view.findViewById(R.id.dipMS2);
volH.setText("");
volM.setText("");
dipH.setText("");
dipM.setText("");
//选项卡 2（第三个选项卡）的代码 - 这里没有太多代码。只是用于创建视图的代码。并显示你好世界。
//在我的代码中引用错误的简单日志猫
09-10 13:49:24.823 2718-2718/com.example.siv.mahalaxmipetroleums E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not find method clickFun1(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'calcBtn'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:4240)
at android.view.View$PerformClick.run(View.java:17721)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
有人能找出其中的错误吗？？？
【问题讨论】：
不要发布您的完整项目，而是发布完整的 logcat。它更有用。 由于我的笔记本电脑内存不足，我没有在模拟器上运行它。我将应用程序复制到我的安卓手机中，然后运行它。有没有办法在手机上找到logcat？？ logcat 出现在同一个地方。无论如何，在物理设备上开发确实是一种不好的做法。您应该仅将其用于最终的预发布测试。 @Rotwang：“在物理设备上开发确实是一种糟糕的做法”——近 20 亿人使用物理设备。很少使用模拟器。欢迎您按照自己的意愿进行开发，但我建议开发人员专注于用户使用的环境：硬件。使用模拟器测试您缺少硬件的场景（例如，不同的操作系统版本）。 @Siva：如果您从 IDE 运行您的应用程序，您access LogCat the same way for both emulators and hardware。 【参考方案1】：java.lang.IllegalStateException: Could not find method clickFun1(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'calcBtn'
您的布局具有android:onClick 属性，引用clickFun1 方法。您的活动中没有该名称的方法。在您的一个片段上有一个同名的方法，但标准的android:onClick 逻辑不会找到那个方法。
处理此问题的选项包括：
删除android:onClick 属性，改为在片段中的此按钮上注册OnClickListener
摆脱片段，将业务逻辑，包括这个clickFun1()方法，移到活动中
使用the data binding library 将android:onClick 属性绑定到您的片段
如果您是 Android 开发新手，我推荐第一个选项。
【讨论】：
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