当我将内容解析器添加到主要活动时，我的应用程序崩溃
[英]When I add in content resolver to main activity,my app crashes
问题描述
Below is error log I am getting
下面是我得到的错误日志
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.android.apppinventory, PID: 14400 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.apppinventory/com.example.android.apppinventory.MainActivity}: java.lang.StringIndexOutOfBoundsException: length=10;
This is an inventory app.这是一个库存应用程序。 Earlier I was interacting with the SQLite database and the app worked well but when I added the concept of content resolver the app crashed.Plz help早些时候我与 SQLite 数据库交互，该应用程序运行良好，但是当我添加内容解析器的概念时，应用程序崩溃了。请帮助
private void displayDatabaseInfo() {
//InventoryDbHelper mDbHelper = new InventoryDbHelper(this);
//SQLiteDatabase db = mDbHelper.getReadableDatabase();
String[] projection = {
InventoryEntry._ID,
InventoryEntry.PRODUCT_NAME,
InventoryEntry.PRODUCT_DESCRIPTION,
InventoryEntry.PRODUCT_PRICE,
InventoryEntry.PRODUCT_QUANTITY,
InventoryEntry.PRODUCT_IMAGE
};
/**Cursor cursor = db.query(InventoryEntry.TABLE_NAME,projection,null,null,null,null,null);**/
Cursor cursor = getContentResolver().query(InventoryEntry.CONTENT_URI,projection,null,null,null);
//Cursor cursor = getContentResolver().query(InventoryEntry.CONTENT_URI,projection,null,null,null);
TextView displayView = (TextView) findViewById(R.id.text_view);
try {
displayView.setText("Number of rows in table are " + cursor.getCount() + "\n\n");
displayView.append(InventoryEntry._ID + "-" + InventoryEntry.PRODUCT_NAME + "\n");
int idColumnIndex = cursor.getColumnIndex(InventoryEntry._ID);
int nameColumnIndex = cursor.getColumnIndex(InventoryEntry.PRODUCT_NAME);
while (cursor.moveToNext()) {
int currentID = cursor.getInt(idColumnIndex);
String currentName = cursor.getString(nameColumnIndex);
displayView.append("\n" + currentID + "-" + currentName);
}
} finally {
cursor.close();
}
}
1 个解决方案
解决方案1
1 2017-02-05 10:11:19
The problem is you are appending the strings to a text view which is not valid.问题是您将字符串附加到无效的文本视图中。 Instead use StringBuilder for appending strings.而是使用StringBuilder来附加字符串。 Then afterwards set that string to text view.然后将该字符串设置为文本视图。 Please refer below code for example.请参考下面的代码示例。
private void displayDatabaseInfo() {
//InventoryDbHelper mDbHelper = new InventoryDbHelper(this);
//SQLiteDatabase db = mDbHelper.getReadableDatabase();
String[] projection = {
InventoryEntry._ID,
InventoryEntry.PRODUCT_NAME,
InventoryEntry.PRODUCT_DESCRIPTION,
InventoryEntry.PRODUCT_PRICE,
InventoryEntry.PRODUCT_QUANTITY,
InventoryEntry.PRODUCT_IMAGE
};
/**Cursor cursor = db.query(InventoryEntry.TABLE_NAME,projection,null,null,null,null,null);**/
Cursor cursor = getContentResolver().query(InventoryEntry.CONTENT_URI,projection,null,null,null);
//Cursor cursor = getContentResolver().query(InventoryEntry.CONTENT_URI,projection,null,null,null);
TextView displayView = (TextView) findViewById(R.id.text_view);
StringBuilder sb = new StringBuilder("");
try {
sb.append("Number of rows in table are " + cursor.getCount() + "\n\n");
sb.append(InventoryEntry._ID + "-" + InventoryEntry.PRODUCT_NAME + "\n");
int idColumnIndex = cursor.getColumnIndex(InventoryEntry._ID);
int nameColumnIndex = cursor.getColumnIndex(InventoryEntry.PRODUCT_NAME);
while (cursor.moveToNext()) {
int currentID = cursor.getInt(idColumnIndex);
String currentName = cursor.getString(nameColumnIndex);
sb.append("\n" + currentID + "-" + currentName);
}
displayView.setText(sb.toString());
} finally {
cursor.close();
}
}
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