RuntimeException：無法實例化活動組件信息 Android

Question

我正在嘗試在 android 中編寫代碼，但無法在我的外部設備上運行。 它總是強制退出。 我已經在 android 中編寫了一兩件事，我總是能夠啟動它們，所以我不知道這個錯誤是從哪里來的。

這是啟動器活動的代碼：

package x.y.alarm;

import java.util.ArrayList;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
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 {

    final int setAlarm = 214;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button add = (Button) findViewById(R.id.add);
        add.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                startActivityForResult(new Intent(MainActivity.this,AlarmScreen.class), setAlarm);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data){
        if(requestCode == setAlarm){
            if(resultCode == RESULT_OK){
                String name = data.getStringExtra("Name");
                String time = data.getStringExtra("Time");  //In h:m format
                String days = data.getStringExtra("Days");  //Seperated by ;

                String[] t = time.split(":");
                String[] d = days.split(";");

                int[] hrsAndMin = new int[t.length];
                for(int i = 0; i < t.length; i++){
                    hrsAndMin[i] = Integer.parseInt(t[i]);
                }

                ArrayList<Day> ds = new ArrayList<Day>();
                for(int i = 0; i < d.length; i++){
                    switch(d[i]){
                    case("Monday"):
                        ds.add(Day.Monday);
                    case("Tuesday"):
                        ds.add(Day.Tuesday);
                    case("Wednesday"):
                        ds.add(Day.Wednesday);
                    case("Thursday"):
                        ds.add(Day.Thursday);
                    case("Friday"):
                        ds.add(Day.Friday);
                    case("Saturday"):
                        ds.add(Day.Saturday);
                    case("Sunday"):
                        ds.add(Day.Sunday);
                    }
                }

                Alarm alarm = new Alarm(name, hrsAndMin[0], hrsAndMin[1] , Status.ON, ds);

                addAlarm(alarm);
            }
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        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);
    }

    private void addAlarm(Alarm alarm){

    }
}

這是 AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="sander.bylemans.alarm"
    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="@style/AppTheme" >
        <activity
            android:name="sander.bylemans.alarm.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="sander.bylemans.alarm.AlarmScreen"
            android:label="@string/title_activity_alarm_screen" >
        </activity>
    </application>

</manifest>

這是我收到的錯誤，我不知道如何解決：

10-27 20:56:52.278: W/dalvikvm(14367): Unable to resolve superclass of Lsander/bylemans/alarm/MainActivity; (4)
10-27 20:56:52.278: W/dalvikvm(14367): Link of class 'Lsander/bylemans/alarm/MainActivity;' failed
10-27 20:56:52.298: W/dalvikvm(14367): threadid=1: thread exiting with uncaught exception (group=0x4001d560)
10-27 20:56:52.398: E/AndroidRuntime(14367): FATAL EXCEPTION: main
10-27 20:56:52.398: E/AndroidRuntime(14367): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{sander.bylemans.alarm/sander.bylemans.alarm.MainActivity}: java.lang.ClassNotFoundException: sander.bylemans.alarm.MainActivity in loader dalvik.system.PathClassLoader[/data/app/sander.bylemans.alarm-2.apk]
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1573)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.os.Handler.dispatchMessage(Handler.java:99)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.os.Looper.loop(Looper.java:130)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.ActivityThread.main(ActivityThread.java:3687)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at java.lang.reflect.Method.invokeNative(Native Method)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at java.lang.reflect.Method.invoke(Method.java:507)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at dalvik.system.NativeStart.main(Native Method)
10-27 20:56:52.398: E/AndroidRuntime(14367): Caused by: java.lang.ClassNotFoundException: sander.bylemans.alarm.MainActivity in loader dalvik.system.PathClassLoader[/data/app/sander.bylemans.alarm-2.apk]
10-27 20:56:52.398: E/AndroidRuntime(14367):    at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
10-27 20:56:52.398: E/AndroidRuntime(14367):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1565)
10-27 20:56:52.398: E/AndroidRuntime(14367):    ... 11 more

我搜索了很長時間以尋找解決方案，但似乎無法找到解決問題的方法。 我嘗試了不同的東西，但它們都不起作用。 如果有人能幫助我，我將永遠感激不盡。

問候

Answer 1

VM 無法找到android.support.v7.app.ActionBarActivity; 檢查支持庫 jar 的位置。 它應該在項目的 libs 文件夾中才能工作

Answer 2

所需的 jar 似乎不在您的 libs 文件夾中。 將 jar 復制到您的 libs 文件夾

您需要確保在以下路徑中檢查了lib

Go to Properties->Java Build Path->Order and Export and make sure the library is checked.