Android 当搜索到的值不';不存在于数据库中
当我搜索数据库中不存在的任何值时,应用程序立即崩溃Android 当搜索到的值不';不存在于数据库中,android,sqlite,Android,Sqlite,当我搜索数据库中不存在的任何值时,应用程序立即崩溃 public String ifExistIn(String stationName) { String query = "SELECT stationName FROM review WHERE stationId" + "='" + stationName + "' OR " + " stationName " + "='" + stationName + "' LIMIT 1"; try (SQLi
public String ifExistIn(String stationName) {
String query = "SELECT stationName FROM review WHERE stationId" +
"='" + stationName + "' OR " + " stationName " + "='" + stationName + "' LIMIT 1";
try (SQLiteDatabase database = this.getWritableDatabase();
Cursor c = database.rawQuery(query, null)) {
c.moveToFirst();
return c.getString(c.getColumnIndex("stationName"));
}
}
活动将可用记录添加到列表视图中
public View.OnClickListener searchStation = new View.OnClickListener() {
@Override
public void onClick(View v) {
String searchString = searchText.getText().toString();
//String useThis = dbHelper.ifExistIn(searchString);
if (list.contains(dbms.ifExistIn(searchString))) {
AlertDialog.Builder builder = new AlertDialog.Builder(SearchAndReview.this);
builder.setTitle("");
builder.setMessage("RECORD ALREADY IN THE LIST ");
builder.setNeutralButton("OK", null);
builder.create().show();
else {
list.add(dbms.ifExistIn(searchString));
listView.setAdapter(arrayAdapter);
}
}
}
};
Android studio日志详细信息致命异常
04-27 13:13:27.386 19845-19845/com.example.fahimghl.reviewapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.fahimghl.reviewapplication, PID: 19845
android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
at android.database.AbstractCursor.checkPosition(AbstractCursor.java:426)
at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
at com.example.fahimghl.reviewapplication.DatabaseHelper.ifExistIn(DatabaseHelper.java:130)
at com.example.fahimghl.reviewapplication.SearchAndReview$10.onClick(SearchAndReview.java:172)
at android.view.View.performClick(View.java:4761)
at android.view.View$PerformClick.run(View.java:19767)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5312)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)
当我搜索数据库中不存在的任何值时,应用程序崩溃
马上
public String ifExistIn(String stationName) {
String query = "SELECT stationName FROM review WHERE stationId" +
"='" + stationName + "' OR " + " stationName " + "='" + stationName + "' LIMIT 1";
try (SQLiteDatabase database = this.getWritableDatabase();
Cursor c = database.rawQuery(query, null)) {
c.moveToFirst();
return c.getString(c.getColumnIndex("stationName"));
}
}
那么您可能正在查询一个空游标
try (SQLiteDatabase database = this.getWritableDatabase();
Cursor c = database.rawQuery(query, null)) {
if (c != null && c.moveToFirst()) {
return c.getString(c.getColumnIndex("stationName"));
}
}
return null;
请注意,try with resources
至少需要api级别19
public String ifExistIn(String stationName) {
String query = "SELECT stationName FROM review WHERE stationId" +
"='" + stationName + "' OR " + " stationName " + "='" + stationName + "' LIMIT 1";
try (SQLiteDatabase database = this.getWritableDatabase();
Cursor c = database.rawQuery(query, null))
if (cursor.moveToFirst()) {
do {
String stationName = c.getString(c.getColumnIndex("stationName"));
} while (cursor.moveToNext());
}
database.close();
c.close();
return stationName;
}
请始终关闭数据库,并用光标post日志显示该列表已初始化?它已初始化。当数据库中不存在值时,它的给定问题。当我搜索右值时,它不会崩溃、返回和填充列表视图。给我一分钟,我将在那里发布日志,你可以查看。请检查更新后的日志,并在这里询问日志