java - Android Manifest无法启动 Activity

我想查看自己制作的数据库的应用程序未运行“查看”按钮。

这是我的日志，是否可能没有声明清单？

Logcat：

    12-14 06:56:56.316: E/AndroidRuntime(1144): FATAL EXCEPTION: main
12-14 06:56:56.316: E/AndroidRuntime(1144): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.jacob.eindproject/com.jacob.eindproject.SQLView}: java.lang.NullPointerException
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.os.Looper.loop(Looper.java:137)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.ActivityThread.main(ActivityThread.java:5103)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at java.lang.reflect.Method.invokeNative(Native Method)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at java.lang.reflect.Method.invoke(Method.java:525)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at dalvik.system.NativeStart.main(Native Method)
12-14 06:56:56.316: E/AndroidRuntime(1144): Caused by: java.lang.NullPointerException
12-14 06:56:56.316: E/AndroidRuntime(1144):     at com.jacob.eindproject.Database.<init>(Database.java:63)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at com.jacob.eindproject.SQLView.onCreate(SQLView.java:14)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.Activity.performCreate(Activity.java:5133)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-14 06:56:56.316: E/AndroidRuntime(1144):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
12-14 06:56:56.316: E/AndroidRuntime(1144):     ... 11 more

这是我的android清单：

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

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="18" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >


    <activity
        android:name="com.jacob.eindproject.Menu"
        android:label="@string/app_name" >
    </activity>

    <activity
        android:name="com.jacob.eindproject.Inleiding"
        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="com.jacob.eindproject.MainActivity"
        android:label="@string/app_name" >
                                    <intent-filter>
                        <action android:name="android.intent.action.MAIN" />
                        <category      android:name="android.intent.category.DEFAULT" />
                </intent-filter>
    </activity>

    <activity
        android:name="com.jacob.eindproject.Ondergewicht"
        android:label="@string/app_name" >
    </activity>

    <activity
        android:name="com.jacob.eindproject.Gezond_gewicht"
        android:label="@string/app_name" >
    </activity>

    <activity
        android:name="com.jacob.eindproject.Overgewicht"
        android:label="@string/app_name" >
    </activity>

    <activity
        android:name="com.jacob.eindproject.Database"
        android:label="@string/app_name" >
    </activity>

    <activity
        android:name="com.jacob.eindproject.SQLite"
        android:label="@string/app_name" >
    </activity>


    <activity
        android:name="com.jacob.eindproject.SQLView"
        android:label="@string/app_name" >

    </activity>

</application>

</manifest>

这是我的视图类：

package com.jacob.eindproject;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class SQLView extends Activity{

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sqlview);
    TextView tv = (TextView) findViewById(R.id.tvSQLinfo);
    Database info = new Database(this);
    info.open();
    String data = info.getData();
    info.close();
    tv.setText(data);





}

}

这是我的view.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">


<TableLayout android:layout_width="fill_parent" android:layout_height="fill_parent"         android:id="@+id/tableLayout1">

    <TableRow>

            <TextView android:text="@string/Names"       android:layout_width="fill_parent" android:layout_height="fill_parent"     android:layout_weight="1"/>

            <TextView android:text="@string/Hotness"   android:layout_width="fill_parent" android:layout_height="fill_parent"     android:layout_weight="1" />

    </TableRow>


  </TableLayout>

    <TextView android:id="@+id/tvSQLinfo" android:layout_width="fill_parent"       android:layout_height="fill_parent" android:text="@string/info"/>

  </LinearLayout>

这是我的数据库类：

package com.jacob.eindproject;

 import android.content.ContentValues;
 import android.content.Context;
 import android.database.Cursor;
 import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;

 import java.sql.*;

  public class Database {

public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "persons_name";
public static final String KEY_HOTNESS = "persons_hotness";

private static final String DATABASE_NAME = "HotOrNotdb";
private static final String DATABASE_TABLE = "peopleTable";
private static final int DATABASE_VERSION = 1;

private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;

private static class DbHelper extends SQLiteOpenHelper{

    public DbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
                KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "      +
                KEY_NAME + " TEXT NOT NULL, " +
                KEY_HOTNESS + " TEXT NOT NULL);"
    );


    }

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
        onCreate(db);
    }
}



public Database(Context c){
    ourContext = c;
}

public Database open() throws SQLException{
    ourHelper = new DbHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close() {
} {
ourHelper.close();
  }



public void createEntry(String name, String hotness) {
    ContentValues cv = new ContentValues();
    cv.put(KEY_NAME, name);
    cv.put(KEY_HOTNESS, hotness);
    ourDatabase.insert(DATABASE_TABLE, null, cv);

}

public String getData() {
    // TODO Auto-generated method stub
    String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_HOTNESS};
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null,      null, null);
    String result = "";

    int iRow = c.getColumnIndex(KEY_ROWID);
    int iName = c.getColumnIndex(DATABASE_NAME);
    int iHotness = c.getColumnIndex(KEY_HOTNESS);

    for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
        result = result + c.getString(iRow) + " " + c.getString(iName) + "  " + c.getString(iHotness) + "\n";


    }

    return null;
}
  }

有人可以帮我吗？会很好！

雅各布

最佳答案

删除这个

<activity
        android:name="com.jacob.eindproject.Database"
        android:label="@string/app_name" >
    </activity>

Database不是activity。