我正在尝试从数据库中检索数据并将其显示在listView上。数据将首先发送到数据库并检索和显示。我没有收到任何错误，但我只是在尝试运行模拟器时应用停止。我真的不知道问题出在哪里
activity.main ＆LT;
RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="368dp"
android:layout_height="495dp"
tools:context="com.instinctcoder.sqlitedb.MainActivity$PlaceholderFragment"
tools:layout_editor_absoluteY="8dp"
tools:layout_editor_absoluteX="8dp">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add"
android:id="@+id/btnAdd"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/list"
android:layout_centerHorizontal="true"
android:layout_alignParentTop="true"
android:layout_above="@+id/btnAdd" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="List All"
android:id="@+id/btnGetAll"
android:layout_alignParentBottom="true"
android:layout_toRightOf="@+id/btnAdd" />
</RelativeLayout>
activity_treatment_details
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Treatment Name"
android:id="@+id/treatmentName"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="30dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Treatment Type"
android:id="@+id/treatmentType"
android:layout_below="@+id/treatmentName"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="29dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Treatment Number"
android:id="@+id/treatmentNumber"
android:layout_below="@+id/treatmentType"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="29dp" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textPersonName"
android:ems="10"
android:id="@+id/editTextTreatmentName"
android:layout_above="@+id/treatmentType"
android:layout_toRightOf="@+id/treatmentName"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
android:ems="10"
android:id="@+id/editTextTreatmentType"
android:layout_above="@+id/treatmentNumber"
android:layout_toRightOf="@+id/treatmentName"
android:layout_alignRight="@+id/editTextTreatmentName"
android:layout_alignEnd="@+id/editTextTreatmentName" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="number"
android:ems="10"
android:id="@+id/editTextTreatmentNumber"
android:layout_alignBottom="@+id/treatmentNumber"
android:layout_alignLeft="@+id/editTextTreatmentType"
android:layout_alignStart="@+id/editTextTreatmentType"
android:layout_alignRight="@+id/editTextTreatmentType"
android:layout_alignEnd="@+id/editTextTreatmentType" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Save"
android:id="@+id/btnSave"
android:layout_alignParentBottom="true"
android:layout_toLeftOf="@+id/btnClose" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Close"
android:id="@+id/btnClose"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Delete"
android:id="@+id/btnDelete"
android:layout_alignTop="@+id/btnSave"
android:layout_toLeftOf="@+id/btnSave" />
</RelativeLayout>
view_treatment_entry
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/treatment_Id"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:visibility="gone" />
<TextView
android:id="@+id/treatment_name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="6dip"
android:paddingTop="6dip"
android:textSize="22sp"
android:textStyle="bold" />
</LinearLayout>
Treatment.java
public class Treatment {
// Labels table name
public static final String TABLE = "Treatment";
// Labels Table Columns names
public static final String KEY_TreatmentID = "TreatmentId";
public static final String KEY_TreatmentName = "TreatmentName";
public static final String KEY_TreatmentType = "TreatmentType";
public static final String KEY_TreatmentNumber = "TreatmentNumber";
// property help us to keep data
public int treatment_ID;
public String treatmentName;
public String treatmentType;
public int treatmentNumber;
}
DBHelper.java
`enter code here`public class DBHelper extends SQLiteOpenHelper {
//version number to upgrade database version
//each time if you Add, Edit table, you need to change the
//version number.
private static final int DATABASE_VERSION = 4;
// Database Name
private static final String DATABASE_NAME = "AbovePostnatalDepression.db";
public DBHelper(Context context ) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
//All necessary tables you like to create will create here
String CREATE_TABLE_TREATMENT = "CREATE TABLE " + Treatment.TABLE + "("
+ Treatment.KEY_TreatmentID + " INTEGER PRIMARY KEY AUTOINCREMENT ,"
+ Treatment.KEY_TreatmentName + " TEXT, "
+ Treatment.KEY_TreatmentNumber + " INTEGER, "
+ Treatment.KEY_TreatmentType + " TEXT )";
db.execSQL(CREATE_TABLE_TREATMENT);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed, all data will be gone!!!
db.execSQL("DROP TABLE IF EXISTS " + Treatment.TABLE);
// Create tables again
onCreate(db);
}
}
TreatmentRepo
public class TreatmentRepo {
private DBHelper dbHelper;
public TreatmentRepo(Context context) {
dbHelper = new DBHelper(context);
}
public int insert(Treatment treatment) {
//Open connection to write data
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(Treatment.KEY_TreatmentNumber,
treatment.treatmentNumber);
values.put(Treatment.KEY_TreatmentType,treatment.treatmentType);
values.put(Treatment.KEY_TreatmentName, treatment.treatmentName);
// Inserting Row
long treatment_ID = db.insert(Treatment.TABLE, null, values);
db.close(); // Closing database connection
return (int) treatment_ID;
}
public void delete(int treatment_ID) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
// It's a good practice to use parameter ?, instead of concatenate string
db.delete(Treatment.TABLE, Treatment.KEY_TreatmentID + "= ?", new String[] { String.valueOf(treatment_ID) });
db.close(); // Closing database connection
}
public void update(Treatment treatment) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(Treatment.KEY_TreatmentNumber, treatment.treatmentNumber);
values.put(Treatment.KEY_TreatmentType,treatment.treatmentType);
values.put(Treatment.KEY_TreatmentName, treatment.treatmentName);
db.update(Treatment.TABLE, values, Treatment.KEY_TreatmentID + "= ?", new String[] { String.valueOf(treatment.treatment_ID) });
db.close(); // Closing database connection
}
public ArrayList<HashMap<String, String>> getTreatmentList() {
//Open connection to read only
SQLiteDatabase db = dbHelper.getReadableDatabase();
String selectQuery = "SELECT " +
Treatment.KEY_TreatmentID + "," +
Treatment.KEY_TreatmentName + "," +
Treatment.KEY_TreatmentType + "," +
Treatment.KEY_TreatmentNumber +
" FROM " + Treatment.TABLE;
ArrayList<HashMap<String, String>> treatmentList = new ArrayList<HashMap<String, String>>();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
HashMap<String, String> treatment = new HashMap<String,
String>();
treatment.put("TreatmentId",
cursor.getString(cursor.getColumnIndex(Treatment.KEY_TreatmentID)));
treatment.put("TreatmentName",
cursor.getString(cursor.getColumnIndex(Treatment.KEY_TreatmentName)));
treatmentList.add(treatment);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return treatmentList;
}
public Treatment getTreatmentById(int Id){
SQLiteDatabase db = dbHelper.getReadableDatabase();
String selectQuery = "SELECT " +
Treatment.KEY_TreatmentID + "," +
Treatment.KEY_TreatmentName + "," +
Treatment.KEY_TreatmentType + "," +
Treatment.KEY_TreatmentNumber +
" FROM " + Treatment.TABLE
+ " WHERE " +
Treatment.KEY_TreatmentID + "=?";// It's a good practice to
use parameter ?, instead of concatenate string
int iCount =0;
Treatment treatment = new Treatment();
Cursor cursor = db.rawQuery(selectQuery, new String[] {
String.valueOf(Id) } );
if (cursor.moveToFirst()) {
do {
treatment.treatment_ID
=cursor.getInt(cursor.getColumnIndex(Treatment.KEY_TreatmentID));
treatment.treatmentName
=cursor.getString(cursor.getColumnIndex(Treatment.KEY_TreatmentName));
treatment.treatmentType
=cursor.getString(cursor.getColumnIndex(Treatment.KEY_TreatmentType));
treatment.treatmentNumber
=cursor.getInt(cursor.getColumnIndex(Treatment.KEY_TreatmentNumber));
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return treatment;
}
TreatmentDetail
public class TreatmentDetail extends AppCompatActivity implements
android.view.View.OnClickListener {
Button btnSave , btnDelete;
Button btnClose;
EditText editTextTreatmentName;
EditText editTextTreatmentType;
EditText editTextTreatmentNumber;
private int _Treatment_Id=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_treatment_details);
btnSave = (Button) findViewById(R.id.btnSave);
btnDelete = (Button) findViewById(R.id.btnDelete);
btnClose = (Button) findViewById(R.id.btnClose);
editTextTreatmentName = (EditText)
findViewById(R.id.editTextTreatmentName);
editTextTreatmentType = (EditText)
findViewById(R.id.editTextTreatmentType);
editTextTreatmentNumber = (EditText)
findViewById(R.id.editTextTreatmentNumber);
btnSave.setOnClickListener(this);
btnDelete.setOnClickListener(this);
btnClose.setOnClickListener(this);
_Treatment_Id =0;
Intent intent = getIntent();
_Treatment_Id =intent.getIntExtra("treatment_Id", 0);
TreatmentRepo repo = new TreatmentRepo(this);
Treatment treatment = new Treatment();
treatment = repo.getTreatmentById(_Treatment_Id);
editTextTreatmentNumber.setText(String.valueOf(treatment.treatmentNumber));
editTextTreatmentName.setText(treatment.treatmentName);
editTextTreatmentType.setText(treatment.treatmentType);
}
public void onClick(View view) {
if (view == findViewById(R.id.btnSave)){
TreatmentRepo repo = new TreatmentRepo(this);
Treatment treatment = new Treatment();
treatment.treatmentNumber=
Integer.parseInt(editTextTreatmentNumber.getText().toString());
treatment.treatmentType=editTextTreatmentType.getText().toString();
treatment.treatmentName=editTextTreatmentName.getText().toString();
treatment.treatment_ID=_Treatment_Id;
if (_Treatment_Id==0){
_Treatment_Id = repo.insert(treatment);
Toast.makeText(this,"New Student
Insert",Toast.LENGTH_SHORT).show();
}else{
repo.update(treatment);
Toast.makeText(this,"Student Record
updated",Toast.LENGTH_SHORT).show();
}
}else if (view== findViewById(R.id.btnDelete)){
TreatmentRepo repo = new TreatmentRepo(this);
repo.delete(_Treatment_Id);
Toast.makeText(this, "Student Record Deleted",
Toast.LENGTH_SHORT);
finish();
}else if (view== findViewById(R.id.btnClose)){
finish();
}
}
}
Mainactivity
public class MainActivity extends ListActivity implements
android.view.View.OnClickListener {
Button btnAdd,btnGetAll;
TextView treatment_Id;
@Override
public void onClick(View view) {
if (view== findViewById(R.id.btnAdd)){
Intent intent = new Intent(this,TreatmentDetail.class);
intent.putExtra("treatment_Id",0);
startActivity(intent);
}else {
TreatmentRepo repo = new TreatmentRepo(this);
ArrayList<HashMap<String, String>> treatmentList =
repo.getTreatmentList();
if(treatmentList.size()!=0) {
ListView lv = getListView();
lv.setOnItemClickListener(new
AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View v
view,int position, long id) {
treatment_Id = (TextView)
view.findViewById(R.id.treatment_Id);
String treatmentId =
treatment_Id.getText().toString();
Intent objIndent = new
Intent(getApplicationContext(),TreatmentDetail.class);
objIndent.putExtra("treatment_Id", Integer.parseInt(
treatmentId));
startActivity(objIndent);
}
});
ListAdapter adapter = new SimpleAdapter(
MainActivity.this,treatmentList, R.layout.activity_view_treatment_entry, new
String[] { "TreatmentId","TreatmentName"}, new int[] {R.id.treatment_Id,
R.id.treatment_name});
setListAdapter(adapter);
}else{
Toast.makeText(this,"No student!",Toast.LENGTH_SHORT).show();
}
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnAdd = (Button) findViewById(R.id.btnAdd);
btnAdd.setOnClickListener(this);
btnGetAll = (Button) findViewById(R.id.btnGetAll);
btnGetAll.setOnClickListener(this);
}
}
答案 0 :(得分：1)
ListActivity拥有自己的布局（由ListView组成），因此如果您想通过调用setContentView()来自定义布局，则必须使用id作为"@android:id/list" } ListView
ListActivity has a default layout由单个组成， 屏幕中央的全屏列表。但是，如果你愿意，you can customize the screen layoutsetting您自己的视图布局 在onCreate（）中使用setContentView()。为此，您自己的观点MUSTcontain a ListView object with the id "@android:id/list"
所以替换这个
android:id="@+id/list"
带
android:id="@android:id/list"
并使用view.getId() == R.id.btnAdd代替view== findViewById(R.id.btnAdd)这是一项昂贵的函数调用
或
您也可以extends AppCompatActivity或Activity使用setOnItemClickListener