Question

我是德国编程的初学者。我想创建一个程序，你可以在某个地方驾驶时计算汽油的成本。所以我想要一个'起始页'，一个'计算页面'和一个给出结果的吐司。我有两个活动。我不确定为什么我的程序不起作用！我希望有人可以帮助我，因为这将是我的考试，对我来说工作非常重要。

主要活动：

       package de.vivian.calci;

    import android.support.v7.app.ActionBarActivity;

    import android.content.Intent;
    import android.os.Bundle;
    import android.view.Menu;
    import android.view.MenuItem;


    import android.view.View;
    import.android.view.View.OnClickListener;
    import android.widget.Button;



    public class MainActivity extends ActionBarActivity
    implements View.OnClickListener{


    private Button beginnen;

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


    //Der Button für den Beginn der Berechnun   
    beginnen= (Button) findViewById(R.id.buttonbeginnen);
        beginnen.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

        Intent intent = new Intent(this, Berechnungsactivity.class);
        startActivity(intent);
        //Bei Drücken des Buttons soll die Berechnungsactivity über ein Intent aufgerufen werden
    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.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();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#CBD0D0" 
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="de.vivian.calci.MainActivity" >

<Button
    android:id="@+id/buttonbeginnen"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="100dp"
    android:text="@string/beginnen"
    android:textColor="#FA5882" />

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="350dp"
    android:contentDescription="@string/description"
    android:src="@drawable/auto" />

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/imageView1"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="138dp"
    android:gravity="center_horizontal"
    android:text="@string/begruessung"
    android:textColor="#000000"
    android:textSize="@dimen/textview_schriftgroesse" />

</RelativeLayout>

第二项活动名为Berechnungsactivity（计算活动）

    package de.vivian.calci;

import android.support.v7.app.ActionBarActivity;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import android.view.View;

public class Berechnungsactivity extends ActionBarActivity{
private Button buttonspritkosten;
private Button buttonabbrechen; 
//Die möglichen Buttons in dieser Activity

private OnClickListener listi= new OnClickListener(){
    //Hier konnte ich mit dem OnClickListener nur über ein Objekt Arbeiten, da es mir sonst einen Fehler angezeigt hat
    @Override
    public void onClick(View v) {
        if (v == buttonspritkosten) {

            TextView textViewPersonenzahl;
            TextView textViewStrecke;
            TextView textViewVerbrauch;
            TextView textViewPreis;
            double berechnung;
            String Personenzahl;
            String Strecke;
            String Verbrauch;
            String Preis;



            // Eingabefelder auslesen       
            textViewPersonenzahl = (TextView) findViewById(R.id.editpersonen);
            textViewStrecke = (TextView) findViewById(R.id.editstrecke);
            textViewVerbrauch = (TextView) findViewById(R.id.editverbrauch);
            textViewPreis = (TextView) findViewById(R.id.editpreis);

            Personenzahl=textViewPersonenzahl.getText().toString();
            Strecke=textViewStrecke.getText().toString();
            Verbrauch=textViewVerbrauch.getText().toString();
            Preis=textViewPreis.getText().toString();

            berechnung= (((((Double.parseDouble(Strecke))/100)*(Double.parseDouble(Verbrauch)))*(Double.parseDouble(Preis)))/(Double.parseDouble(Personenzahl)));

            Toast einToast = Toast.makeText(v.getContext(), "Die Kosten pro Person betragen:" + String.valueOf(berechnung), Toast.LENGTH_SHORT);
            einToast.show();
            ;
            //Wenn also hier der Button berechnen gedrückt wird, sollen die Kosten berechnet werden und ein Toast mit dem ergebnis ausgegeben werden
        } else if (v == buttonabbrechen) {
            finish();

            // sollte der User Abbrechen drücken, soll die App beendet werden
        }
        // TODO Auto-generated method stub

    }
};


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_berechnungsactivity);
        buttonspritkosten= (Button) findViewById(R.id.buttonspritkosten);
        buttonspritkosten.setOnClickListener(listi);
        buttonabbrechen= (Button) findViewById(R.id.buttonabbrechen);
        buttonabbrechen.setOnClickListener(listi);

    }






    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.berechnungsactivity, 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();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


}

xml文件到第二个活动berechnungsactivity（计算活动）

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
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"
android:background="#CBD0D0"
tools:context="de.vivian.calci.Berechnungsactivity" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:text="Bitte fülle folgende Felder aus:"
    android:textSize="@dimen/textview_schriftgroesse"
    android:textColor="#FA5882" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView1"
    android:layout_below="@+id/textView1"
    android:layout_marginTop="50dp"
    android:text="Personenzahl"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:textColor="@color/black" />

<TextView
    android:id="@+id/textView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView2"
    android:layout_below="@+id/textView2"
    android:layout_marginTop="50dp"
    android:text="Strecke in km"
    android:textAppearance="?android:attr/textAppearanceSmall" 
    android:textColor="@color/black"/>

<TextView
    android:id="@+id/textView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView3"
    android:layout_below="@+id/textView3"
    android:layout_marginTop="50dp"
    android:text="Verbrauch in l"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:textColor="@color/black" />

<TextView
    android:id="@+id/textView5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView4"
    android:layout_below="@+id/textView4"
    android:layout_marginTop="50dp"
    android:text="Literpreis in €"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:textColor="@color/black" /> <!-- Länge des Eingabefeldes -->


<Button
    android:id="@+id/buttonspritkosten"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="110dp"
    android:text="@string/buttonspritkosten"
    android:textColor="#FA5882" />

<EditText
    android:id="@+id/editpersonen"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/textView2"
    android:layout_alignRight="@+id/textView1"
    android:ems="6"
    android:inputType="numberDecimal" />

<EditText
    android:id="@+id/editstrecke"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/textView3"
    android:layout_alignLeft="@+id/editpersonen"
    android:ems="6"
    android:inputType="numberDecimal" >

    <requestFocus />
</EditText>

<EditText
    android:id="@+id/editverbrauch"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/textView4"
    android:layout_alignLeft="@+id/editstrecke"
    android:ems="6"
    android:inputType="numberDecimal" />

<EditText
    android:id="@+id/editpreis"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/textView5"
    android:layout_alignLeft="@+id/editverbrauch"
    android:ems="6"
    android:inputType="numberDecimal" />

<Button
    android:id="@+id/buttonabbrechen"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/buttonspritkosten"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="50dp"
    android:text="@string/buttonabbrechen"
    android:textColor="#FA5882" />

</RelativeLayout>

manifest.xml

   <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="de.vivian.calci"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="16" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@android:style/Theme.Light"> >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".Berechnungsactivity"
            android:label="@string/title_activity_berechnungsactivity" >
        </activity>
    </application>

</manifest>

Logcat说：

06-19 07:22:10.393: E/AndroidRuntime(775): FATAL EXCEPTION: main
06-19 07:22:10.393: E/AndroidRuntime(775): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.vivian.calci/de.vivian.calci.MainActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.os.Handler.dispatchMessage(Handler.java:99)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.os.Looper.loop(Looper.java:137)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.ActivityThread.main(ActivityThread.java:5041)
06-19 07:22:10.393: E/AndroidRuntime(775):  at java.lang.reflect.Method.invokeNative(Native Method)
06-19 07:22:10.393: E/AndroidRuntime(775):  at java.lang.reflect.Method.invoke(Method.java:511)
06-19 07:22:10.393: E/AndroidRuntime(775):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
06-19 07:22:10.393: E/AndroidRuntime(775):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
06-19 07:22:10.393: E/AndroidRuntime(775):  at dalvik.system.NativeStart.main(Native Method)
06-19 07:22:10.393: E/AndroidRuntime(775): Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.support.v7.app.AppCompatDelegateImplBase.onCreate(AppCompatDelegateImplBase.java:113)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.support.v7.app.AppCompatDelegateImplV7.onCreate(AppCompatDelegateImplV7.java:146)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.support.v7.app.AppCompatActivity.onCreate(AppCompatActivity.java:59)
06-19 07:22:10.393: E/AndroidRuntime(775):  at de.vivian.calci.MainActivity.onCreate(MainActivity.java:25)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.Activity.performCreate(Activity.java:5104)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
06-19 07:22:10.393: E/AndroidRuntime(775):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
06-19 07:22:10.393: E/AndroidRuntime(775):  ... 11 more

styles.xml

    <?xml version="1.0" encoding="UTF-8"?>
<resources>

    <!-- Base application theme, dependent on API level. This theme is replaced 
        by AppBaseTheme from res/values-vXX/styles.xml on newer devices. -->
    <style name="AppBaseTheme" parent="Theme.AppCompat.Light">
        <!-- Theme customizations available in newer API levels can go in res/values-vXX/styles.xml, 
            while customizations related to backward-compatibility can go here. -->
    </style>

    <!-- Application theme. -->
    <style name="AppTheme" parent="AppBaseTheme">
        <!-- All customizations that are NOT specific to a particular API-level 
            can go here. -->



        <item name="android:windowNoTitle">true</item> <!-- Hides the Action Bar test -->
        <item name="android:windowFullscreen">true</item> <!-- Hides the status bar test -->




    </style>

</resources>

Answer 1

根据你得到的错误，你应该改变这一行：

public class Berechnungsactivity extends ActionBarActivity{

这一个：

public class Berechnungsactivity extends Activity{

，其他一切都会像它一样

Answer 2

您遇到此问题的原因是您尝试应用主题的活动是扩展ActionBarActivity，这需要应用AppCompat主题。

将Java继承从ActionBarActivity更改为Activity，并将主题保留在清单中。

Answer 3

您正在使用

android:theme="@android:style/Theme.Light"

作为您申请的主题。由于你的styles.xml有

<style name="AppBaseTheme" parent="Theme.AppCompat.Light">
        <!-- Theme customizations available in newer API levels
             can go in res/values-vXX/styles.xml, 
             while customizations related to backward-compatibility can go here. -->
</style>

您应该在清单中使用AppBaseTheme作为主题。

android:theme="@android:style/AppBaseTheme

Answer 4

在您的manifest.xml <application>代码更改theme属性文件中

android:theme="@style/AppTheme"

第一个程序不起作用，我不知道为什么

4 个答案: