我想将"*.csv"文件（在android资产文件夹中）转换为SQLite表。
然后，使用listview显示表。（：读取csv-使用->sqlite表-使用->显示列表视图）
但都是错误。
请帮忙。
- 对不起，我的英语不清楚
- 我没有任何生根装置。总是在我的真实设备（而不是测试设备或虚拟机）中运行
代码中仍然存在错误。并且未创建"test.db"文件。
logcat:Nullpointerexception，无法打开文件进行读取。。。等
public class FirstActivity extends Activity {
public static DBHelper mDBManager;
private SQLiteDatabase db;
Cursor c;
ListView list = (ListView) findViewById(R.id.listView1);
String arrname[] = null;
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mtname);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.first);
mDBManager = new DBHelper(this);
db = mDBManager.getWritableDatabase();
db = mDBManager.getReadableDatabase();
Log.d("FirstActivity:onCreate", "oncreate");
displayList();
}
private void displayList() {
// TODO Auto-generated method stub
c = mDBManager.SortAllRows();
Log.d("FirstActivity:displayList", "displayList");
int i = 0;
if (c.moveToFirst()) {
do {
arrname[i] = c.getString(c.getColumnIndexOrThrow("_name"));
} while (c.moveToNext());
}
list.setAdapter(adapter);
c.close();
db.close();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.first, menu);
return true;
}
}
public class DBHelper extends SQLiteOpenHelper {
private static String DB_PATH = "/mnt/sdcard/";
private static final String TABLE_NAME = "test";
private DBHelper dbHelper;
private SQLiteDatabase db;
private String fileName = "test.csv"; // "file:///android_asset/test.csv"; //"/mnt/sdcard/test.csv";
private Context mcontext;
public DBHelper(Context context)
{
super(context, DB_PATH + "test.db", null, 1);
mcontext = context;
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE " + TABLE_NAME + "(_index INTEGER PRIMARY KEY AUTOINCREMENT, _name TEXT, _ad TEXT, _ca TEXT, _sp TEXT);");
AssetManager am = mcontext.getAssets();
InputStream is = null;
try {
is = am.open(fileName);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("DBHelper:onCreate", "csv file open");
}
BufferedReader buffer = null;
buffer = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
/** I tried this way. but there was all error(Including the above way). NullPointerException **
* for '*. csv' file to change the table of sqlite. (csv file->sqlite table)
//InputStream in = mcontext.getAssets().open(fileName);
//BufferReader buffer = new BufferedReader(new InputStreamReader(in, "UTF-8"));
//AssetManager am = mcontext.getAssets();
//BufferedReader buffer = new BufferedReader(new InputStreamReader(am.open(fileName), "UTF-8"));
//FileReader fr = new FileReader(new File("file:///android_asset/","test.csv"));
//BufferedReader buffer = new BufferedReader(fr);
//AssetFileDescriptor descriptor = am.openFd(fileName);
//FileReader file = new FileReader(descriptor.getFileDescriptor());
//FileReader file = new FileReader(fileName);
//BufferedReader buffer = new BufferedReader(file);
*/
String line = "";
String columns = "_index, _name, _ad, _ca, _sp";
String str1 = "INSERT INTO " + TABLE_NAME + " (" + columns + ") values(";
String str2 = ");";
db.beginTransaction();
try {
while ((line = buffer.readLine()) != null) {
StringBuilder sb = new StringBuilder(str1);
String[] str = line.split(",");
sb.append("'" + str[0] + "',");
sb.append(str[1] + "',");
sb.append(str[2] + "',");
sb.append(str[3] + "'");
sb.append(str[4] + "'");
sb.append(str2);
db.execSQL(sb.toString());
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
db.setTransactionSuccessful();
db.endTransaction();
Log.d("DBHelper:onCreate","DB CREATE");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
Log.w("DBHelper:onUpgrade", "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
public Cursor SortAllRows() {
return db.query(TABLE_NAME, new String[] { "_index", "_name", "_ad", "_ca", "_sp" }, null, null, null, null, null, "_name" + " ASC");
}
public void close() {
Log.d("DBHelper:close","DBhelper close");
if (dbHelper != null) {
dbHelper.close();
}
}
}
11-27 15:13:15.893: E/(19898): Can't open file for reading
11-27 15:13:15.893: E/(19898): Can't open file for reading
11-27 15:13:15.973: D/memalloc(19898): ion: Mapped buffer base:0x4c3ab000 size:1536000 offset:0 fd:78
11-27 15:13:16.024: I/Adreno200-EGLSUB(19898): <ConfigWindowMatch:2081>: Format RGBA_8888.
11-27 15:13:16.024: D/memalloc(19898): ion: Mapped buffer base:0x4c728000 size:1536000 offset:0 fd:81
11-27 15:13:16.024: D/memalloc(19898): ion: Unmapping buffer base:0x4be87000 size:1536000
11-27 15:13:16.024: D/memalloc(19898): ion: Unmapping buffer base:0x4c3ab000 size:1536000
11-27 15:13:16.034: D/memalloc(19898): ion: Mapped buffer base:0x4be87000 size:1536000 offset:0 fd:74
11-27 15:13:16.704: D/memalloc(19898): ion: Mapped buffer base:0x4c3ab000 size:1536000 offset:0 fd:78
11-27 15:13:18.606: I/Adreno200-EGLSUB(19898): <ConfigWindowMatch:2081>: Format RGBA_8888.
11-27 15:13:18.606: D/memalloc(19898): ion: Mapped buffer base:0x4c89f000 size:1536000 offset:0 fd:87
11-27 15:13:18.636: D/memalloc(19898): ion: Mapped buffer base:0x4ca16000 size:1536000 offset:0 fd:90
11-27 15:13:18.646: D/memalloc(19898): ion: Unmapping buffer base:0x4c728000 size:1536000
11-27 15:13:18.646: D/memalloc(19898): ion: Unmapping buffer base:0x4be87000 size:1536000
11-27 15:13:18.646: D/memalloc(19898): ion: Unmapping buffer base:0x4c3ab000 size:1536000
11-27 15:13:19.837: D/memalloc(19898): ion: Mapped buffer base:0x4be87000 size:1536000 offset:0 fd:74
11-27 15:13:29.196: D/FirstActivity:onCreate(19898): mDBManager
11-27 15:13:29.196: D/FirstActivity:onCreate(19898): oncreate
11-27 15:13:29.196: I/FirstActivity:displayList(19898): displayList
11-27 15:13:29.196: W/dalvikvm(19898): threadid=1: thread exiting with uncaught exception (group=0x40ce31f8)
11-27 15:13:29.196: E/AndroidRuntime(19898): FATAL EXCEPTION: main
11-27 15:13:29.196: E/AndroidRuntime(19898): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test/com.example.test.FirstActivity}: java.lang.NullPointerException
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1961)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1986)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.ActivityThread.access$600(ActivityThread.java:128)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1152)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.os.Handler.dispatchMessage(Handler.java:99)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.os.Looper.loop(Looper.java:137)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.ActivityThread.main(ActivityThread.java:4449)
11-27 15:13:29.196: E/AndroidRuntime(19898): at java.lang.reflect.Method.invokeNative(Native Method)
11-27 15:13:29.196: E/AndroidRuntime(19898): at java.lang.reflect.Method.invoke(Method.java:511)
11-27 15:13:29.196: E/AndroidRuntime(19898): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)
11-27 15:13:29.196: E/AndroidRuntime(19898): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
11-27 15:13:29.196: E/AndroidRuntime(19898): at dalvik.system.NativeStart.main(Native Method)
11-27 15:13:29.196: E/AndroidRuntime(19898): Caused by: java.lang.NullPointerException
11-27 15:13:29.196: E/AndroidRuntime(19898): at com.example.test.DBHelper.SortAllRows(DBHelper.java:139)
11-27 15:13:29.196: E/AndroidRuntime(19898): at com.example.test.FirstActivity.displayList(FirstActivity.java:50)
11-27 15:13:29.196: E/AndroidRuntime(19898): at com.example.test.FirstActivity.onCreate(FirstActivity.java:38)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.Activity.performCreate(Activity.java:4465)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
11-27 15:13:29.196: E/AndroidRuntime(19898): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1925)
11-27 15:13:29.196: E/AndroidRuntime(19898): ... 11 more
您没有在构造函数中初始化db变量。因此：
SortAllRows()方法在执行return db.query(TABLE_NAME, new String[] { "_index", "_name", "_ad", "_ca", "_sp" }, null, null, null, null, null, "_name" + " ASC"); 时抛出NullPointerException
此外，您的表名将是test，而不是test.db，因为private static final String TABLE_NAME = "test";
为什么不将*.csv文件包含到SQlite数据库中，然后将该数据库添加到assets文件夹中。这将使事情变得简单，然后您可以轻松地从数据库中获取详细信息。