我的代码在这里EmployeeAppActivity
我的代码在没有图像的列表视图中运行良好。我在列表视图中需要员工照片，当图像从数据库添加到列表视图时出现错误。请帮帮我。
// Primitive Variables
String selected_ID = "";
// Widget GUI Declare
EditText txtEname, txtDesig, txtSalary;
Button btnAddEmployee, btnUpdate, btnDelete;
ListView lvEmployees;
// DB Objects
DBHelper helper;
SQLiteDatabase db;
// Adapter Object
SimpleCursorAdapter adapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Init DB Objects
helper = new DBHelper(this);
// Widget GUI Init
txtEname = (EditText) findViewById(R.id.txtEname);
txtDesig = (EditText) findViewById(R.id.txtDesig);
txtSalary = (EditText) findViewById(R.id.txtSalary);
lvEmployees = (ListView) findViewById(R.id.lvEmployees);
btnAddEmployee = (Button) findViewById(R.id.btnAdd);
btnUpdate = (Button) findViewById(R.id.btnUpdate);
btnDelete = (Button) findViewById(R.id.btnDelete);
// Attached Listener
btnAddEmployee.setOnClickListener(this);
btnUpdate.setOnClickListener(this);
btnDelete.setOnClickListener(this);
lvEmployees.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapter, View v,
int position, long id) {
String name, desig, salary;
byte[] empphoto;
// Display Selected Row of Listview into EditText widget
Cursor row = (Cursor) adapter.getItemAtPosition(position);
selected_ID = row.getString(0);
name = row.getString(1);
desig = row.getString(2);
salary = row.getString(3);
empphoto=row.getBlob(4);
txtEname.setText(name);
txtDesig.setText(desig);
txtSalary.setText(salary);
}
});
// Fetch Data from database
fetchData();
}
@Override
public void onClick(View v) {
// Perform CRUD Operation
if (v == btnAddEmployee) {
// Add Record with help of ContentValues and DBHelper class object
Bitmap b=BitmapFactory.decodeResource(getResources(), R.drawable.icon);
//Bitmap b=BitmapFactory.decodeFile(imagepath);
//ContentValues cv=new ContentValues();
ByteArrayOutputStream bos=new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.JPEG, 90, bos);
byte[] photo=bos.toByteArray();
ContentValues values = new ContentValues();
values.put(DBHelper.C_ENAME, txtEname.getText().toString());
values.put(DBHelper.C_DESIGNATION, txtDesig.getText().toString());
values.put(DBHelper.C_SALARY, txtSalary.getText().toString());
values.put(DBHelper.C_Dp, photo);
// Call insert method of SQLiteDatabase Class and close after
// performing task
db = helper.getWritableDatabase();
db.insert(DBHelper.TABLE, null, values);
db.close();
clearFields();
Toast.makeText(this, "Employee Added Successfully",
Toast.LENGTH_LONG).show();
// Fetch Data from database and display into listview
fetchData();
}
if (v == btnUpdate) {
// Update Record with help of ContentValues and DBHelper class
// object
ContentValues values = new ContentValues();
values.put(DBHelper.C_ENAME, txtEname.getText().toString());
values.put(DBHelper.C_DESIGNATION, txtDesig.getText().toString());
values.put(DBHelper.C_SALARY, txtSalary.getText().toString());
// Call update method of SQLiteDatabase Class and close after
// performing task
db = helper.getWritableDatabase();
db.update(DBHelper.TABLE, values, DBHelper.C_ID + "=?",
new String[] { selected_ID });
db.close();
// Fetch Data from database and display into listview
fetchData();
Toast.makeText(this, "Record Updated Successfully",
Toast.LENGTH_LONG).show();
clearFields();
}
if (v == btnDelete) {
// Call delete method of SQLiteDatabase Class to delete record and
// close after performing task
db = helper.getWritableDatabase();
db.delete(DBHelper.TABLE, DBHelper.C_ID + "=?",
new String[] { selected_ID });
db.close();
// Fetch Data from database and display into listview
fetchData();
Toast.makeText(this, "Record Deleted Successfully",
Toast.LENGTH_LONG).show();
clearFields();
}
}
// Clear Fields
private void clearFields() {
txtEname.setText("");
txtDesig.setText("");
txtSalary.setText("");
}
// Fetch Fresh data from database and display into listview
private void fetchData() {
db = helper.getReadableDatabase();
Cursor c = db.query(DBHelper.TABLE, null, null, null, null, null, null);
adapter = new SimpleCursorAdapter(
this,
R.layout.row,
c,
new String[] { DBHelper.C_ENAME, DBHelper.C_SALARY, DBHelper.C_DESIGNATION ,DBHelper.C_Dp},
new int[] { R.id.lblEname, R.id.lblSalary, R.id.lblDesignation,R.id.empdp });
lvEmployees.setAdapter(adapter);
}
DBHelper类在这里
static final String DATABASE = "empapp.db";
static final int VERSION = 1;
static final String TABLE = "emp";
static final String C_ID = "_id";
static final String C_ENAME = "ename";
static final String C_DESIGNATION = "designation";
static final String C_SALARY = "salary";
static final String C_Dp = "photo";
// Override constructor
public DBHelper(Context context) {
super(context, DATABASE, null, VERSION);
}
// Override onCreate method
@Override
public void onCreate(SQLiteDatabase db) {
// Create Employee table with following fields
// _ID, ENAME, DESIGNATION and SALARY
db.execSQL("CREATE TABLE " + TABLE + " ( " + C_ID
+ " INTEGER PRIMARY KEY AUTOINCREMENT, " + C_ENAME + " text, "
+ C_DESIGNATION + " text, " + C_SALARY + " text, " + C_Dp+ " BLOB )");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop old version table
db.execSQL("Drop table " + TABLE);
// Create New Version table
onCreate(db);
}
Logcat错误
09-30 03：45：38.139：E / AndroidRuntime（30628）：致命异常：主要 09-30 03：45：38.139：E / AndroidRuntime（30628）： android.database.sqlite.SQLiteException：未知错误（代码0）： 无法将BLOB转换为字符串09-30 03：45：38.139： E / AndroidRuntime（30628）：at android.database.CursorWindow.nativeGetString（Native Method）09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.database.CursorWindow.getString（CursorWindow.java:434)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.database.AbstractWindowedCursor.getString（AbstractWindowedCursor.java:51） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.SimpleCursorAdapter.bindView（SimpleCursorAdapter.java:150） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.CursorAdapter.getView（CursorAdapter.java:250)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.AbsListView.obtainView（AbsListView.java:2159)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.ListView.makeAndAddView（ListView.java:1831)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.ListView.fillDown（ListView.java:674)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.ListView.fillFromTop（ListView.java:735)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.ListView.layoutChildren（ListView.java:1652)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.AbsListView.onLayout（AbsListView.java:1994)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.View.layout（View.java:14003)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.view.ViewGroup.layout（ViewGroup.java:4375)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.widget.LinearLayout.setChildFrame（LinearLayout.java:1663） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.LinearLayout.layoutVertical（LinearLayout.java:1521） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.LinearLayout.onLayout（LinearLayout.java:1434)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.View.layout（View.java:14003)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.view.ViewGroup.layout（ViewGroup.java:4375)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.widget.FrameLayout.onLayout（FrameLayout.java:448)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.View.layout（View.java:14003)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.view.ViewGroup.layout（ViewGroup.java:4375)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.widget.LinearLayout.setChildFrame（LinearLayout.java:1663） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.LinearLayout.layoutVertical（LinearLayout.java:1521） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.widget.LinearLayout.onLayout（LinearLayout.java:1434)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.View.layout（View.java:14003)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.view.ViewGroup.layout（ViewGroup.java:4375)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.widget.FrameLayout.onLayout（FrameLayout.java:448)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.View.layout（View.java:14003)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.view.ViewGroup.layout（ViewGroup.java:4375)09-30 03:45:38.139： E / AndroidRuntime（30628）：at android.view.ViewRootImpl.performLayout（ViewRootImpl.java:1892)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:1711） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:989)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:4351） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.Choreographer $ CallbackRecord.run（Choreographer.java:749） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.Choreographer.doCallbacks（Choreographer.java:562)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.Choreographer.doFrame（Choreographer.java:532)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:735） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.os.Handler.handleCallback（Handler.java:725)09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.os.Handler.dispatchMessage（Handler.java:92）09-30 03：45：38.139：E / AndroidRuntime（30628）：at android.os.Looper.loop（Looper.java:137）09-30 03：45：38.139： E / AndroidRuntime（30628）：at android.app.ActivityThread.main（ActivityThread.java:5039)09-30 03：45：38.139：E / AndroidRuntime（30628）：at java.lang.reflect.Method.invokeNative（Native Method）09-30 03：45：38.139：E / AndroidRuntime（30628）：at java.lang.reflect.Method.invoke（Method.java:511)09-30 03:45:38.139： E / AndroidRuntime（30628）：at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:793） 09-30 03：45：38.139：E / AndroidRuntime（30628）：at com.android.internal.os.ZygoteInit.main（ZygoteInit.java:560)09-30 03：45：38.139：E / AndroidRuntime（30628）：at dalvik.system.NativeStart.main（原生方法）
答案 0 :(得分：0)
在您的数据库中，您将图片网址保存为字符串
static final String C_Dp =“photo”;
但是如何用这条线将你的图像变成blob？
empphoto = row.getBlob（4）;
你可以从sql lite获取路径为字符串，然后从这个路径获取drawabale图像并将其显示在listview中包含的图像视图中
File imgFile = new File("your file path from sqlite");
if(imgFile.exists()){
Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
ImageView myImage = (ImageView) findViewById(R.id.imageviewTest);
myImage.setImageBitmap(myBitmap);
答案 1 :(得分：0)
SimpleCursorAdapter使用cursor.getString从数据库中检索值，如下所示 the Source Code .Hence，SimpleCursorAdapter不了解如何处理blob数据。所以在这种情况下你必须创建自己的自定义视图binder。看看下面的示例代码
<强> EmployeeAppActivity.java
public class EmployeeAppActivity extends AppCompatActivity {
// DB Objects
DBHelper helper;
SQLiteDatabase db;
SimpleCursorAdapter adapter;
private ListView lvEmployees;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Init DB Objects
helper = new DBHelper(this);
lvEmployees = (ListView) findViewById(R.id.lvEmployees);
populateDummyDataInDb();
fetchData();
}
private void fetchData() {
db = helper.getReadableDatabase();
Cursor c = db.query(DBHelper.TABLE, null, null, null, null, null, null);
adapter = new SimpleCursorAdapter(
this,
R.layout.row,
c,
new String[]{DBHelper.C_ENAME, DBHelper.C_DP},
new int[]{R.id.lblEname, R.id.empdp});
adapter.setViewBinder(new EmployeeListViewBinder());
lvEmployees.setAdapter(adapter);
}
private void populateDummyDataInDb() {
Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.person_image_empty);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.JPEG, 90, bos);
byte[] photo = bos.toByteArray();
ContentValues values = new ContentValues();
values.put(DBHelper.C_ENAME, "Waleed Sarwar");
values.put(DBHelper.C_DP, photo);
db = helper.getWritableDatabase();
db.insert(DBHelper.TABLE, null, values);
}
}
<强> EmployeeListViewBinder.java
public class EmployeeListViewBinder implements SimpleCursorAdapter.ViewBinder {
@Override
public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
int viewID = view.getId();
switch (viewID) {
case R.id.lblEname:
TextView textView = (TextView) view;
textView.setText(cursor.getString(cursor.getColumnIndex(DBHelper.C_ENAME)));
break;
case R.id.empdp:
ImageView imageView= (ImageView) view;
byte[] imageBytes = cursor.getBlob(cursor.getColumnIndex(DBHelper.C_DP));
if (imageBytes != null) {
// Pic image from database
imageView.setImageBitmap(BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length));
} else {
// If image not found in database , assign a default image
//imageView.setBackgroundResource(R.drawable.bubble_a);
}
break;
}
return true;
}
}
<强> DBHelper.jave
public class DBHelper extends SQLiteOpenHelper {
public static final String DATABASE = "empapp.db";
public static final int VERSION = 1;
public static final String TABLE = "emp";
public static final String C_ID = "_id";
public static final String C_ENAME = "ename";
public static final String C_DP = "photo";
public DBHelper(Context context) {
super(context, DATABASE, null, VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE + " ( " + C_ID
+ " INTEGER PRIMARY KEY AUTOINCREMENT, " + C_ENAME + " text, "
+ C_DP + " BLOB )");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop old version table
db.execSQL("Drop table " + TABLE);
// Create New Version table
onCreate(db);
}
}
<强> activity_main.xml中
<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"
tools:context=".MainActivity">
<ListView
android:id="@+id/lvEmployees"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:listitem="@layout/row" />
</RelativeLayout>
<强> row.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:id="@+id/empdp"
android:layout_width="80dp"
android:layout_height="80dp"
android:src="@drawable/person_image_empty" />
<TextView
android:id="@+id/lblEname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="5dp"
android:layout_marginStart="5dp"
android:text="Waleed Sarwar" />
</LinearLayout>