android - 我的带有标签的滑动 View 的 Android 计算器应用程序崩溃了

Question

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 View )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 View 的代码。并显示 Hello World 。

//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)

请问有人能找到其中的错误吗？？？

Answer 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，指的是 clickFun1方法。您的 Activity 中没有该名称的方法。在您的一个 fragment 上有一个同名的方法，但标准 android:onClick逻辑不会找到那个。

处理此问题的选项包括:

删除 android:onClick属性，而是注册一个 OnClickListener在 fragment 中的这个按钮上

去掉fragment，移动业务逻辑，包括这个clickFun1()方法，进入 Activity

使用the data binding library绑android:onClick归因于您的 fragment

如果您是 Android 开发新手，我推荐第一个选项。