Question

我做了什么

我在布局中创建了一个GridView。这个GridView我想填写我创建的Google Documentations的ImageAdapter：Hello GridView

我的图片的图片路径，我保存到我的数据库，我想填写它。因为在我的Datbase中，所有内容都是我在Activity中编写的一个String函数，它将String []更改为Int []，但我无法访问我的ImageAdapter。之后我应用了尼基塔夫人告诉我的变化。此外，我更改为lil，将String []更改为int []（现在正在工作）。

问题

我需要更改以将Int []添加到我的ImageAdapter中，它导入我的图片并将它们显示在GrindView中。现在我有一个Nullpointer异常：

public int getCount() {
        return mThumbIds.length;
    }

守则：

这是我的SmileyConfigActivity.java的代码：

package de.retowaelchli.filterit;

import de.retowaelchli.filterit.database.SmileyDBAdapter;
import de.retowaelchli.filterit.stats.ImageAdapter;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.GridView;


public class SFilterConfigActivity extends Activity {

    //Variablen deklarieren
    private String name;
    private String keyword;
    private Integer[] info;
    private SmileyDBAdapter SmileyHelper;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sfilter_config);

      SmileyHelper = new SmileyDBAdapter(this);

      getImages();

    }


public Integer[] getImages(){



    SmileyHelper.open();

    Cursor c = SmileyHelper.getAllSmileys();
    startManagingCursor(c);

    String[] picture = new String[] { SmileyDBAdapter.INFO };

    int i;
    for (i=0;i< picture.length-1;i++) {
        info[i]=Integer.parseInt(picture[i+1]);

    }

    SmileyHelper.close();

    //Hier wird die Grindview gefüllt
    GridView gridview = (GridView) findViewById(R.id.SmileyGrind);
    gridview.setAdapter(new ImageAdapter(this, info));

    return info;

}



public void onClickSConfigSave(View v){

    EditText edtTextName = (EditText)findViewById(R.id.SFConfigName);
    EditText edtTextKeyword = (EditText)findViewById(R.id.SFConfigKeyword);

    name = edtTextName.getText().toString();
    keyword = edtTextKeyword.getText().toString();

    final Intent i = new Intent(this, SmileyActivity.class);
    startActivity(i);
    }
}

这是我的ImageAdapter.java的代码：

    package de.retowaelchli.filterit.stats;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;


import de.retowaelchli.filterit.SFilterConfigActivity;

public class ImageAdapter extends BaseAdapter {

    private Context mContext;

    public ImageAdapter(Context c, Integer[] imageIds) {
        mContext = c;
        mThumbIds = imageIds;
    }

    //This Guy down here is giving me the NullpointerExcpetion now
    public int getCount() {
        return mThumbIds.length;
    }

    public Object getItem(int position) {
        return null;
    }

    public long getItemId(int position) {
        return 0;
    }

    // create a new ImageView for each item referenced by the Adapter
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView imageView;
        if (convertView == null) {  // if it's not recycled, initialize some attributes
            imageView = new ImageView(mContext);
            imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setPadding(8, 8, 8, 8);
        } else {
            imageView = (ImageView) convertView;
        }

        imageView.setImageResource(mThumbIds[position]);
        return imageView;
    }


    // references to our images
    private Integer[] mThumbIds;
}

这就是我将图片存储到数据库的方式（我只保存到它们所在的位置）：

    int drawableID = context.getResources().getIdentifier("angel", "drawable", getPackageName());
    iv.setImageResource(drawableID);

    String info = String.valueOf(drawableID);

    mDbHelper.open();

    mDbHelper.createSmiley("You have received a heavenly message", info);
    mDbHelper.close();

这是我得到的错误记录：

10-04 13:26:25.776: ERROR/AndroidRuntime(10099): FATAL EXCEPTION: main
10-04 13:26:25.776: ERROR/AndroidRuntime(10099): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.retowaelchli.filterit/de.retowaelchli.filterit.SFilterConfigActivity}: java.lang.NullPointerException
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1816)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1837)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.ActivityThread.access$1500(ActivityThread.java:132)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1033)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.os.Looper.loop(Looper.java:143)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.ActivityThread.main(ActivityThread.java:4196)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at java.lang.reflect.Method.invokeNative(Native Method)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at java.lang.reflect.Method.invoke(Method.java:507)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at dalvik.system.NativeStart.main(Native Method)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099): Caused by: java.lang.NullPointerException
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at de.retowaelchli.filterit.stats.ImageAdapter.getCount(ImageAdapter.java:25)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.widget.GridView.setAdapter(GridView.java:131)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at de.retowaelchli.filterit.SFilterConfigActivity.getImages(SFilterConfigActivity.java:54)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at de.retowaelchli.filterit.SFilterConfigActivity.onCreate(SFilterConfigActivity.java:30)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1780)
10-04 13:26:25.776: ERROR/AndroidRuntime(10099):     ... 11 more

谢谢你的帮助！

Answer 1

在ImageAdapter中尝试创建构造函数

public ImageAdapter(Context c, Integer[] imageIds) {
    mContext = c;
    mThumbIds = imageIds;
}

并在getImagesMethod替换

gridview.setAdapter(new ImageAdapter(this));

与

gridview.setAdapter(new ImageAdapter(this, info));

Answer 2

这里似乎缺少很多相关信息，但如果填写空白，我会更新答案。第一个问题是你在getAllSmileys函数中检索的是什么？

您需要了解的是，游标就像结果的内存表。因此，您需要通过使用移动命令告诉光标从哪个记录获取，否则它是未经过资格化的。因此，假设您的smilleys存储在SmileyDBAdapter.INFO列中，那么您可以像这样检索它们：

SmileyHelper.open();

Cursor c = SmileyHelper.getAllSmileys();

if(c!=null)
{
   int i=0;
   info = new int[c.getCount()]();

   //get the column index
   int infoIndex = c.getColumnIndex(SmileyDBAdapter.INFO);

   while(c.moveToNext()){
       String infoItem = c.getString(infoIndex );
       int infoItemInteger = Integer.parseInt(infoItem);
       info[i++] =infoItemInteger;
   }
}

c.close();

SmileyHelper.close();

您将图像ID作为字符串存储在数据库中，这使得事情变得更加复杂。无需将可绘制资源ID解析和输入数据库中的文本列。只需将列类型更改为整数，并始终使用图像的整数。

您只需使用Cursor.getInt（）来检索值。

Answer 3

我正在尝试这个并找到了这个解决方案。唯一有效的。

public Integer[] getImages(){

        SmileyHelper.open();

        Cursor c = SmileyHelper.getAllSmileys();    

        ArrayList<Integer> infoList = new ArrayList<Integer>();

        c.getColumnIndex(SmileyDBAdapter.INFO);
        int ColumnIndex = c.getColumnIndex(SmileyDBAdapter.INFO);

        if(c!=null)
        {

           while(c.moveToNext()){
               String infoItem = c.getString( ColumnIndex );
               infoList.add(Integer.parseInt(infoItem));
           }
        }

        info = infoList.toArray(new Integer[]{});

        c.close();


        SmileyHelper.close();

        //Hier wird die Grindview gefüllt
        GridView gridview = (GridView) findViewById(R.id.SmileyGrind);
        gridview.setAdapter(new ImageAdapter(this, info));

        return info;

    }

使用Int []填充ImageAdapter

3 个答案: