[英]Reasons why my Android App would crash on my phone consistently, but not on my emulator
[英]Why does my app crash in my mobile phone but not on AVD emulator?
我編寫了一個使用SQLite db的應用程序。 在我不使用SQLite而是僅使用普通字段和普通字段存儲數據的第一階段,我的應用程序在手機中的運行情況就很好。 但是現在,當我使用SQLite有效存儲和提取數據時,我的應用程序在手機中崩潰了。 有趣的一點是,它在我的計算機上的AVD模擬器上運行良好。 知道為什么會這樣嗎?
這是我的數據庫類:
public class WordsDB extends SQLiteOpenHelper {
static final String DATABASE_NAME = "DicDB";
static final String TermTable = "Terms";
static final String ID = "id";
static final String Selected = "selected";
static final String Term = "term";
static final String Br = "br_phon";
static final String NAm = "nam_phon";
static final String Type = "type";
static final String Noun = "noun";
static final String Verb = "verb";
static final String Adjective = "adjective";
static final String Adverb = "adverb";
static final String DefTable = "Definitions";
static final String Def = "definition";
static final String Ex = "example";
public static final int DATABASE_VERSION = 1;
private static final String TERM_TABLE_CREATE = "Create table " + TermTable +
"(" + ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
Selected + " VARCHAR(5) ," +
Term + " VARCHAR(20) ," +
Br + " VARCHAR(20) ," +
NAm + " VARCHAR(20) ," +
Type + " VARCHAR(10) ," +
Noun + " VARCHAR(20) ," +
Verb + " VARCHAR(20) ," +
Adjective + " VARCHAR(20) ," +
Adverb + " VARCHAR(20)) ";
private static final String DEF_TABLE_CREATE = "Create table " + DefTable +
"(" + ID + " INTEGER PRIMARY KEY ," +
Def + " VARCHAR(30) ," +
Ex + " VARCHAR(160)) ";
public WordsDB(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL(TERM_TABLE_CREATE);
db.execSQL(DEF_TABLE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
db.execSQL("DROP TABLE IF EXISTS " + TermTable);
db.execSQL("DROP TABLE IF EXISTS " + DefTable);
onCreate(db);
}
}
這是DataSource類:
public class WordsDS {
private WordsDB dbHelper;
private SQLiteDatabase db;
public WordsDS(Context context) {
dbHelper = new WordsDB(context);
}
public void open() throws SQLException {
db = dbHelper.getWritableDatabase();
}
public void close() {
db.close();
}
// Methods to inset, update and extract data from table
.......
}
我在主要活動中從WordsDS類中創建一個對象,並通過開放方法獲得可寫數據庫,依此類推;在其他類中,我使用WordsDS對象並通過該對象插入,更新和提取數據。
首先,您必須卸載應用程序才能進行全新安裝。 這意味着所有創建的數據庫將在您的手機上擦除。 這將確保如果添加了新列或發生了數據庫結構更改,那么將創建數據庫。 您可能會認為onUpgrade方法可以為您完成此操作,但不會成功!
至於在移動設備上調試應用程序。 首先,您必須在計算機上安裝手機的驅動程序。 然后,您現在可以隨后運行adb logcat。
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