android - 如何在android中从sqlite数据库中插入和获取数据？

Question

我已经编写了这段代码，通过使用“for”循环将数据插入数据库，我也想查看数据库的数据，但应用程序崩溃了。我找不到它的问题请帮助我...

package com.smshah.database;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;


public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    TextView t1=(TextView)findViewById(R.id.textView1);
    TextView t2=(TextView)findViewById(R.id.textView2);
    TextView t3=(TextView)findViewById(R.id.textView3);

    SQLiteDatabase db = openOrCreateDatabase("mapdb", MODE_PRIVATE, null);
    db.execSQL("CREATE TABLE IF NOT EXISTS maptb (rssi INT(4),xval INT(4),yval INT(4));");
    int x=0;
    int y=0;
    int r=0;

    for (int i = 0; i <= 100; i++) 
    {
        db.execSQL("INSERT INTO maptb VALUES("+r+","+x+","+y+");");
        x = x + 1;
        r = r - 1;
    }

    Cursor resultSet = db.rawQuery("Select * from maptb",null);
    resultSet.moveToFirst();
    int rssi = resultSet.getInt(resultSet.getColumnIndex("rssi"));
    int xval = resultSet.getInt(resultSet.getColumnIndex("xval"));
    int yval = resultSet.getInt(resultSet.getColumnIndex("yval"));

    t1.setText(rssi);
    t2.setText(xval);
    t3.setText(yval);

    db.close();
}

}

日志

08-04 03:12:17.842: W/ResourceType(13662): No package identifier when getting value for resource number 0x00000000
08-04 03:12:17.852: D/AndroidRuntime(13662): Shutting down VM
08-04 03:12:17.852: W/dalvikvm(13662): threadid=1: thread exiting with uncaught exception (group=0x40c0ea68)
08-04 03:12:17.882: E/AndroidRuntime(13662): FATAL EXCEPTION: main
08-04 03:12:17.882: E/AndroidRuntime(13662): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.smshah.database/com.smshah.database.MainActivity}: android.content.res.Resources$NotFoundException: String resource ID #0x0
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.ActivityThread.access$600(ActivityThread.java:128)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.os.Looper.loop(Looper.java:137)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.ActivityThread.main(ActivityThread.java:4517)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at java.lang.reflect.Method.invokeNative(Native Method)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at java.lang.reflect.Method.invoke(Method.java:511)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at dalvik.system.NativeStart.main(Native Method)
08-04 03:12:17.882: E/AndroidRuntime(13662): Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x0
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.content.res.Resources.getText(Resources.java:260)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.widget.TextView.setText(TextView.java:3680)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at com.smshah.database.MainActivity.onCreate(MainActivity.java:47)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.Activity.performCreate(Activity.java:4470)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053)
08-04 03:12:17.882: E/AndroidRuntime(13662):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934)
08-04 03:12:17.882: E/AndroidRuntime(13662):

Answer 1

看来你的崩溃与数据库没有任何关系。它说没有找到资源异常。你能指出 MainActivity 第 47 行的内容吗？您应该已经设置了 TextView 的内容。

编辑

你推送给 TextView 的是 int，text view 假定这些值是资源标识符而不是字符串。因此，请执行以下操作以使您的 TextView 写入字符串而不是资源标识符。

t1.setText(rssi + "");
t2.setText(xval + "");
t3.setText(yval + "");