Question

我通过观看教程视频开发了这个Android应用程序，其中他们共享了下载代码的链接。此应用程序在单击按钮时保存表单的值。单击时，它会显示插入值的消息，但我无法在sqlite中看到任何值，也无法检索任何值。

以下是该应用的完整代码： -

add.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:padding="20dp" >

    <EditText
        android:id="@+id/editTitle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="hint_title" >

        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/editDuedate"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:hint="hint_duedate"
        android:inputType="date" />

    <EditText
        android:id="@+id/editCourse"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:hint="hint_course" />

    <EditText
        android:id="@+id/editNotes"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:hint="notes"
        android:inputType="textMultiLine" android:lines="6"/>

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >

        <Button
            android:id="@+id/addAssignment"
            android:layout_width="140dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:onClick="addAssignment"
            android:text="add" />

        <Button
            android:id="@+id/viewBtn"
            android:layout_width="140dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="view" android:onClick="viewAssignments"/>

    </LinearLayout>

</LinearLayout>

assignment_item.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <TextView
    android:id="@+id/rowDate"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:padding="10dp"
    android:scrollbars="vertical"
    android:fadingEdge="vertical"

    android:layout_alignParentRight="true"
  />
  <TextView
    android:id="@+id/row"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"  
    android:padding="10dp"
    android:scrollbars="vertical"
    android:fadingEdge="vertical"

    android:layout_alignParentLeft="@+id/rowDate"
  />
</RelativeLayout>

main.xml中：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:padding="20dp" >

    <ScrollView
        android:id="@+id/scrollView1"
        android:layout_width="fill_parent"
        android:layout_height="331dp"
        android:layout_weight="0.44"
        android:fillViewport="true" >

        <LinearLayout
            android:id="@+id/linearLayout1"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" >

            <ListView
                android:id="@+id/listView1"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:layout_weight="0" >
            </ListView>
        </LinearLayout>
    </ScrollView>

    <Button
        android:id="@+id/add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:text="add" />

</LinearLayout>

addassignment.java：

public class addassignment extends Activity {

    DBAdapter db = new DBAdapter(this); 

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

    }
    public void addAssignment(View v)
    {
        Log.d("test", "adding");
        //get data from form
        EditText nameTxt = (EditText)findViewById(R.id.editTitle);
        EditText dateTxt = (EditText)findViewById(R.id.editDuedate);
        EditText courseTxt = (EditText)findViewById(R.id.editCourse);
        EditText notesTxt = (EditText)findViewById(R.id.editNotes);

           db.open();        
           long id = db.insertRecord(nameTxt.getText().toString(), dateTxt.getText().toString(), courseTxt.getText().toString(), notesTxt.getText().toString());        
           db.close();

        nameTxt.setText("");
        dateTxt.setText("");
        courseTxt.setText("");
        notesTxt.setText("");
        Toast.makeText(addassignment.this,"Assignment Added", Toast.LENGTH_LONG).show();  

    }

    public void viewAssignments(View v)
    {
    Intent i = new Intent(this, AssignmentTracker.class);
    startActivity(i);
    }

}

AssignmentTracker.java：

public class AssignmentTracker extends Activity {
    /** Called when the activity is first created. */

    //DBAdapter db = new DBAdapter(this); 

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        Button addBtn = (Button)findViewById(R.id.add);
        addBtn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent i = new Intent(AssignmentTracker.this, addassignment.class);
                startActivity(i);
            }
        });


        try {           
            String destPath = "/data/data/" + getPackageName() + "/databases/AssignmentDB";
            File f = new File(destPath);            
            if (!f.exists()) {          
                CopyDB( getBaseContext().getAssets().open("mydb"), 
                    new FileOutputStream(destPath));
            }
        } catch (FileNotFoundException e) {         
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        //DBAdapter db = new DBAdapter(this); 


        //---add an assignment---
        /*
        db.open();        
        long id = db.insertRecord("Hello World", "2/18/2012", "DPR 224", "First Android Project");        
        id = db.insertRecord("Workbook Exercises", "3/1/2012", "MAT 100", "Do odd numbers");
        db.close();
        */

        //---get all Records---
        /*
        db.open();
        Cursor c = db.getAllRecords();
        if (c.moveToFirst())
        {
            do {          
                DisplayRecord(c);
            } while (c.moveToNext());
        }
        db.close();
        */

        /*
        //---get a Record---
        db.open();
        Cursor c = db.getRecord(2);
        if (c.moveToFirst())        
            DisplayRecord(c);
        else
            Toast.makeText(this, "No Assignments found", Toast.LENGTH_LONG).show();
        db.close();
        */


        //---update Record---
        /*
        db.open();
        if (db.updateRecord(1, "Hello Android", "2/19/2012", "DPR 224", "First Android Project"))
            Toast.makeText(this, "Update successful.", Toast.LENGTH_LONG).show();
        else
            Toast.makeText(this, "Update failed.", Toast.LENGTH_LONG).show();        
        db.close();
        */

        /*
        //---delete a Record---
        db.open();
        if (db.deleteRecord(1))
            Toast.makeText(this, "Delete successful.", Toast.LENGTH_LONG).show();
        else
            Toast.makeText(this, "Delete failed.", Toast.LENGTH_LONG).show();            
        db.close();
        */
    }

    private class DBAdapter extends BaseAdapter {
        private LayoutInflater mInflater;
        //private ArrayList<>

        @Override
        public int getCount() {

            return 0;
        }

        @Override
        public Object getItem(int arg0) {

            return null;
        }

        @Override
        public long getItemId(int arg0) {

            return 0;
        }

        @Override
        public View getView(int arg0, View arg1, ViewGroup arg2) {

            return null;
        }

    }

    public void CopyDB(InputStream inputStream, OutputStream outputStream) 
    throws IOException {
        //---copy 1K bytes at a time---
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, length);
        }
        inputStream.close();
        outputStream.close();
    }

    public void DisplayRecord(Cursor c)
    {
        Toast.makeText(this, 
                "id: " + c.getString(0) + "\n" +
                "Title: " + c.getString(1) + "\n" +
                "Due Date:  " + c.getString(2),
                Toast.LENGTH_SHORT).show();        
    } 

    public void addAssignment(View view)
    {

        Intent i = new Intent("com.pinchtapzoom.addassignment");
        startActivity(i);
        Log.d("TAG", "Clicked");
    }

}

DBAdapter.java：

public class DBAdapter {
    public static final String KEY_ROWID = "id";
    public static final String KEY_TITLE = "title";
    public static final String KEY_DUEDATE = "duedate";
    public static final String KEY_COURSE = "course";
    public static final String KEY_NOTES = "notes";
    private static final String TAG = "DBAdapter";

    private static final String DATABASE_NAME = "AssignmentsDB";
    private static final String DATABASE_TABLE = "assignments";
    private static final int DATABASE_VERSION = 3;

    private static final String DATABASE_CREATE =
        "create table if not exists assignments (id integer primary key autoincrement, "
        + "title VARCHAR not null, duedate date, course VARCHAR, notes VARCHAR );";

    private final Context context;    

    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

    public DBAdapter(Context ctx) 
    {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }

    private static class DatabaseHelper extends SQLiteOpenHelper 
    {
        DatabaseHelper(Context context) 
        {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) 
        {
            try {
                db.execSQL(DATABASE_CREATE);    
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS contacts");
            onCreate(db);
        }
    }    

    //---opens the database---
    public DBAdapter open() throws SQLException 
    {
        db = DBHelper.getWritableDatabase();
        return this;
    }

    //---closes the database---    
    public void close() 
    {
        DBHelper.close();
    }

    //---insert a record into the database---
    public long insertRecord(String title, String duedate, String course, String notes) 
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_TITLE, title);
        initialValues.put(KEY_DUEDATE, duedate);
        initialValues.put(KEY_COURSE, course);
        initialValues.put(KEY_NOTES, notes);
        return db.insert(DATABASE_TABLE, null, initialValues);
    }

    //---deletes a particular record---
    public boolean deleteContact(long rowId) 
    {
        return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
    }

    //---retrieves all the records---
    public Cursor getAllRecords() 
    {
        return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_TITLE,
                KEY_DUEDATE, KEY_COURSE, KEY_NOTES}, null, null, null, null, null);
    }

    //---retrieves a particular record---
    public Cursor getRecord(long rowId) throws SQLException 
    {
        Cursor mCursor =
                db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                KEY_TITLE, KEY_DUEDATE, KEY_COURSE, KEY_NOTES}, 
                KEY_ROWID + "=" + rowId, null, null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;
    }

    //---updates a record---
    public boolean updateRecord(long rowId, String title, String duedate, String course, String notes) 
    {
        ContentValues args = new ContentValues();
        args.put(KEY_TITLE, title);
        args.put(KEY_DUEDATE, duedate);
        args.put(KEY_COURSE, course);
        args.put(KEY_NOTES, notes);
        return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
    }
}

我的清单：

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

    <uses-sdk android:minSdkVersion="7" />

    <application

        android:label="@string/app_name" >
        <activity
            android:name=".AssignmentTracker"
            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=".addassignment"></activity>
    </application>

</manifest>

Answer 1

使用sqlite数据库浏览器检查您的表是否包含值 http://sqlitebrowser.org/

Answer 2

在DatabaseHelper类中使用add below函数并在插入后调用它或者想要查看数据库

public static void DbBackup() {
        File file = new File(Environment.getExternalStorageDirectory(),DATABASE_NAME);
        if (file.exists())
            file.delete();
        try {
            File dbFile = new File(DB_PATH + DB_NAME);
            FileInputStream in = new FileInputStream(dbFile);
            OutputStream out = new FileOutputStream(file);
            byte[] buf = new byte[1024];
            int len;
            try {
                while ((len = in.read(buf)) > 0)
                    out.write(buf, 0, len);
            } catch (IOException e) {
                e.printStackTrace();
            }
            in.close();
            out.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

}

{{1} }是数据库文件的路径当您调用此函数时，它会将数据库文件从数据库复制到SdCard，现在将此数据库文件传输到您的计算机并使用任何SQLite浏览器打开它以查看数据库的内容。

Answer 3

您可以使用模拟器的DDMS访问此文件夹。

您可以在Eclipse中查看表结构和数据。以下是步骤

1.为Eclipse安装SqliteManagerPlugin。

2.从此处下载* .jar文件

3.将* .jar文件放入eclipse / dropins /

文件夹中

4.Restart eclipse

5.在eclipse的右上角，单击DDMS图标

6.在左侧面板中选择适当的模拟器

7.在主面板的File Explorer选项卡中，转到/ data / data / [app package] / databases

8.在DDMS图标下，当您选择数据库时，应该会有一个新的数据库蓝色图标亮起。单击它，您将看到一个Questoid Sqlite Manager选项卡打开以查看您的数据。

下载此Questoid SqLiteBrowser：http://www.java2s.com/Code/JarDownload/com.questoid/com.questoid.sqlitebrowser_1.2.0.jar.zip

解压缩并将其放入eclipse / dropins

了解更多信息see here

之后，您可以看到数据库中的数据是否已插入？

Answer 4

要了解您在android studio中创建的sqlite数据库，您需要按照简单的步骤进行操作：

1.运行您的申请

2.转到工具---＆gt; Android ----＆gt;设备监视器

3.在左侧面板中找到您的应用程序名称

4.然后单击“文件资源管理器”选项卡

5.选择数据文件夹

6.再次选择数据文件夹，找到您的应用程序或模块名称

7.单击您的数据库名称

8.在右上角的窗口中，您可以选择从设备中提取文件。

9.单击它并将其保存在PC上

有关更多信息，请点击此链接。 http://www.c-sharpcorner.com/UploadFile/e14021/know-where-database-is-stored-in-android-studio/

要查看db文件中的数据，您需要下载sqlite浏览器或在任何浏览器中添加相同的插件，这样您就需要在浏览器中打开文件并查看数据。

从http://sqlitebrowser.org/

下载浏览器

无法从sqlite中查看和检索值

4 个答案: