小编phi*_*lip的帖子

我有这个数据库使用sqlite,我有关闭光标的问题,它说这Application did not close the cursor or database object that was opened here是logcat

10-18 08:40:56.354: E/Cursor(331): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteCursor.<init>(SQLiteCursor.java:210)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
10-18 08:40:56.354: E/Cursor(331):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
10-18 08:40:56.354: E/Cursor(331):  at standard.internet.marketing.mymovingfriend.SQLHandler.checkMove(SQLHandler.java:1094)
10-18 08:40:56.354: E/Cursor(331):  at standard.internet.marketing.mymovingfriend.ListMovingNames$3.onKey(ListMovingNames.java:98)
10-18 08:40:56.354: E/Cursor(331):  at android.view.View.dispatchKeyEvent(View.java:3735)
10-18 08:40:56.354: E/Cursor(331): …

我用javascript创建了一个计算矢量坐标的程序,一切都很顺利,因为我有正确的公式,但是当我尝试在javascript中使用Math.cos来计算143.1301的余弦时,它从科学计算器返回0.1864而不是0.7999为什么是那？任何人都可以向我解释原因吗？还请给我这个问题的解决方案...在此先感谢... :)这里;我的代码示例

function cyltoxec(a)  
{
    ans = Math.cos(a);  
    return ans.toFixed(4);
}
var = x;
return cyltoxec(x);

我是 android 新手，我在理解如何为画布设置动画时遇到问题。基本上，当球应该从楼梯上掉下来时，我已经画了一个红球和一个楼梯

这是它的样子。

谁能帮助我我应该使用什么方法？如果你能给我提供一个非常有帮助的源代码。

这是我的源代码：

绘图视图.java

package com.ballandstair;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.View;

public class DrawingView extends View {
    DrawingView(Context context) {
        super(context);
    }

    protected void onDraw(Canvas canvas){
        super.onDraw(canvas);
        Paint paint = new Paint();
        Path path = new Path();

        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.RED);
        paint.setAntiAlias(true);
        canvas.drawCircle(100, 50, 25, paint);

        paint.setColor(Color.BLUE);
        paint.setStyle(Paint.Style.FILL);
        path.moveTo(75, 75);
        path.lineTo(125, 75);
        path.lineTo(125, 125);
        path.lineTo(175, 125);
        path.lineTo(175, 175);
        path.lineTo(225, 175);
        path.lineTo(225, 225);
        path.lineTo(275, 225);
        path.lineTo(275, 275);
        path.lineTo(325, 275);
        path.lineTo(325, 325);
        path.lineTo(75, 325); …

我已经两天都收到这个错误,我找不到代码的问题.

这是数据库代码.

SQLHandler.java

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class SQLHandler {
    public static final String KEY_ROOMMOVEHOLDER = "roommoveholder";
    public static final String KEY_ROOM = "room";

    public static final String KEY_ITEMMOVEHOLDER = "itemmoveholder";
    public static final String KEY_ITEMNAME = "itemname";
    public static final String KEY_ITEMVALUE = "itemvalue";
    public static final String KEY_ROOMHOLDER = "roomholder";

    public static final String KEY_MOVENAME = "movename";
    public static final String KEY_ID1 = "_id";
    public static final String KEY_ID2 …

不知道我错过了什么，但每次edittext聚焦时，下划线颜色都不会适应我设置的自定义颜色。这是我的主题代码供参考

<style name="EditTextHintWhite" parent="@style/AppTheme">
   <item name="color">@color/white</item>
   <item name="android:textColorHint">@color/white</item>
   <item name="colorControlNormal">@color/white</item>
   <item name="colorControlActivated">@color/white</item>
   <item name="colorError">@color/white</item>
</style>

正如你所看到的，我已将它们全部设置为白色，但不知何故，当焦点edittext聚焦时，下划线变成绿色

这是我的布局代码

<com.google.android.material.textfield.TextInputLayout
        android:id="@+id/email"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/EditTextHintWhite">

        <androidx.appcompat.widget.AppCompatEditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="@string/email"
            android:inputType="textEmailAddress"
            android:maxLines="1"
            android:shadowColor="@color/white"
            android:singleLine="true"
            android:textColor="@color/white"
            app:backgroundTint="@color/white" />

</com.google.android.material.textfield.TextInputLayout>

如何使用此类值在javascript中将小数位限制为4？e是指数,因为我使用十个值的幂.toFixed()似乎不起作用.

1.0531436913408342e-7
-5.265718456704172e-7
8.425149530726674e7

我最近得到这个错误我知道原因,但我不知道如何解决它.

这是logcat的错误:

10-05 02:34:00.177: E/SQLiteDatabase(1111): close() was never explicitly called on database '/data/data/standard.internet.marketing.mymovingfriend/databases/mymovingfriend' 
10-05 02:34:00.177: E/SQLiteDatabase(1111): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1943)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:1007)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:986)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:1051)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:770)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:221)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:157)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at standard.internet.marketing.mymovingfriend.SQLHandler.open(SQLHandler.java:178)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at standard.internet.marketing.mymovingfriend.ListMovingNames$1.onClick(ListMovingNames.java:71)
10-05 02:34:00.177: E/SQLiteDatabase(1111):     at android.view.View.performClick(View.java:3511) …