Android Hello GridView教程不会显示图像

Question

第一次海报！

我是 Android 开发新手，一直在遵循 Google 的 HelloView 教程，没有出现任何问题...直到 HelloGridView 教程。由于某种原因，我无法显示任何图像，只能显示黑色背景。我最初遵循本教程：

http://developer.android.com/ resources/tutorials/views/hello-gridview.html

但转到这个几乎相同的：

http://developer.android.com/guide/tutorials/views/hello-gridview.html

为了通过删除 OnItemClickListener 代码来消除一些额外的复杂性并缩小我可能的问题区域。我的代码与提供的代码完全相同，逐字复制和粘贴。我什至从教程中下载了原始示例文件，并将它们放在 res\drawable 文件夹中，R 代码似乎已成功识别它们并相应地更新了其生成的代码。我正在使用 Android target 1.5，并在我的 Droid X 上和使用 Android 模拟器上尝试过这个程序。我拥有所有导入内容，代码编译并运行良好。但是，我的活动仅显示黑屏；没有图像出现。当我单击黑色背景时，橙色方块出现在图像应有的位置。我发现有一两篇文章提到了这个问题，但它总是伴随着一些更大、更明显的问题，并且从未得到解决。我将在下面列出我的代码和LogCat以供参考。

我注意到我的 LogCat 提到：

WARN/ImageView(364): Unable to find resource: 2130837507

这让我看到了这个线程： 为什么 setImageResource 不显示任何内容？ 详细介绍了使用 setImageDrawable 而不是 setImageResource 的可能解决方法。我使用以下代码行实现了这一点：

imageView.setImageDrawable(mContext.getResources().getDrawable(mThumbIds[position]));

但是，这只会导致 Resources$NotFoundException 导致我的代码崩溃（也在下面记录）。

结论
我认为 Android 教程不需要解决方法，所以我猜测我遇到了某种配置问题。经过几个小时的搜索和尝试后，我还没有找到解决方案，因此我认为值得进行一些讨论。另外，这是我的第一篇文章，如果您发现任何明显的失礼，请告诉我。我提前为即将到来的墙代码表示歉意，尽管我认为数据太少可能比太多更糟糕。 ：D

谢谢大家！

马恩野兽

更新
我尝试在 mThumbIds 中使用 R.drawable.icon，在它和我的一张图片之间交替使用。没有显示任何图片，但图标显示了。然后我尝试了我的图片的 .png 版本，但这也不起作用。我复制了 icon.png 图像并在 Paint 中对其进行了编辑（在 Android 家伙上留了胡子 :D）并将其保存为 dummyicon.png。我在它和图标之间交替，但这也不起作用。最后，我删除了所有图标引用，只使用了我的 png 图像，但奇怪的是，运行时，所有图像都显示为图标，即使我没有在 mThumbIds 中引用它！这与之前的行为不同，之前什么也没有显示。我将几个虚拟图标更改为虚拟图标，当运行时，这些图像没有显示/只是黑色。所有其他图像（mThumbIds 中重复的一个 png 转换图像）仍然显示为图标。

最后，我再次用图标替换了转换后的 png 图像引用，在图标和虚拟图标之间交替，现在它们都没有出现 - 只是再次出现黑屏。因此，看起来 dummyicon 和 icon 在引用时都没有产生任何结果，只是一个黑色空间，但我转换后的 png 图像 - chloie1.png - 产生了 icon.png。我添加了另一张图片 - chloie2.png - 并在 chloie1 和 chloie2 之间交替，但只有 chloie1 显示图标图像。因此，这是我的 mThumbIds 目前的状态：

private Integer[] mThumbIds = {
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2,
        R.drawable.chloie1, R.drawable.chloie2
};

这是模拟器的输出：

解决方案！
事实证明，由于某种原因，本教程不适用于 JPEG 图像。此外，我做了一个愚蠢的假设，只是将扩展名从 .jpg 更改为 .png，它在图像查看器中仍然有效，但仍然被 Android 识别为 jpg。现在我已经在 Paint 中编辑了每张图片，然后保存为 PNG 类型，一切似乎都工作正常。

但是我仍然觉得这里有问题。我假设 android 应该处理 .jpg 图像，因为他们提供了 jpeg 作为示例图片。如果有人知道为什么 PNG 有效而 JPG 无效，请回复。同时，这个简单的修复就可以了。

感谢您的帮助！

参考

main.xml：

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/gridview"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:columnWidth="90dp"
    android:numColumns="auto_fit"
    android:verticalSpacing="10dp"
    android:horizontalSpacing="10dp"
    android:stretchMode="columnWidth"
    android:gravity="center"
/>

HelloGridViewActivity.java

package com.marnbeast.android;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;

public class HelloGridViewActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        GridView gridview = (GridView) findViewById(R.id.gridview);
        gridview.setAdapter(new ImageAdapter(this));

    }
}

ImageAdapter.java

package com.marnbeast.android;

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

public class ImageAdapter extends BaseAdapter {
    private Context mContext;

    public ImageAdapter(Context c) {
        mContext = c;
    }

    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 = {
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7
    };
}

LogCat 无法查找资源：

07-24 06:00:04.564: WARN/ResourceType(364): getEntry failing because entryIndex 3 is beyond type entryCount 1
07-24 06:00:04.564: WARN/ResourceType(364): Failure getting entry for 0x7f020003 (t=1 e=3) in package 0: 0x80000001
07-24 06:00:04.584: WARN/ImageView(364): Unable to find resource: 2130837507
07-24 06:00:04.584: WARN/ImageView(364): android.content.res.Resources$NotFoundException: Resource ID #0x7f020003
07-24 06:00:04.584: WARN/ImageView(364):     at android.content.res.Resources.getValue(Resources.java:891)
07-24 06:00:04.584: WARN/ImageView(364):     at android.content.res.Resources.getDrawable(Resources.java:579)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.ImageView.resolveUri(ImageView.java:485)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.ImageView.setImageResource(ImageView.java:270)
07-24 06:00:04.584: WARN/ImageView(364):     at com.marnbeast.android.ImageAdapter.getView(ImageAdapter.java:41)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.AbsListView.obtainView(AbsListView.java:1274)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.GridView.onMeasure(GridView.java:934)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.View.measure(View.java:7964)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3023)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.View.measure(View.java:7964)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:464)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:278)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.View.measure(View.java:7964)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3023)
07-24 06:00:04.584: WARN/ImageView(364):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.View.measure(View.java:7964)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.ViewRoot.performTraversals(ViewRoot.java:763)
07-24 06:00:04.584: WARN/ImageView(364):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1633)
07-24 06:00:04.584: WARN/ImageView(364):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-24 06:00:04.584: WARN/ImageView(364):     at android.os.Looper.loop(Looper.java:123)
07-24 06:00:04.584: WARN/ImageView(364):     at android.app.ActivityThread.main(ActivityThread.java:4363)
07-24 06:00:04.584: WARN/ImageView(364):     at java.lang.reflect.Method.invokeNative(Native Method)
07-24 06:00:04.584: WARN/ImageView(364):     at java.lang.reflect.Method.invoke(Method.java:521)
07-24 06:00:04.584: WARN/ImageView(364):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
07-24 06:00:04.584: WARN/ImageView(364):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
07-24 06:00:04.584: WARN/ImageView(364):     at dalvik.system.NativeStart.main(Native Method)

使用 .setImageDrawable 解决方法后，LogCat 资源未出现异常：

    07-24 07:02:50.234: ERROR/AndroidRuntime(390): Uncaught handler: thread main exiting due to uncaught exception
07-24 07:02:50.245: ERROR/AndroidRuntime(390): android.content.res.Resources$NotFoundException: Resource ID #0x7f020003
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.content.res.Resources.getValue(Resources.java:891)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.content.res.Resources.getDrawable(Resources.java:579)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at com.marnbeast.android.ImageAdapter.getView(ImageAdapter.java:40)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.widget.AbsListView.obtainView(AbsListView.java:1274)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.widget.GridView.onMeasure(GridView.java:934)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.View.measure(View.java:7964)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3023)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.View.measure(View.java:7964)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:464)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:278)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.View.measure(View.java:7964)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3023)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.View.measure(View.java:7964)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.ViewRoot.performTraversals(ViewRoot.java:763)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1633)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.os.Looper.loop(Looper.java:123)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at android.app.ActivityThread.main(ActivityThread.java:4363)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at java.lang.reflect.Method.invokeNative(Native Method)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at java.lang.reflect.Method.invoke(Method.java:521)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
07-24 07:02:50.245: ERROR/AndroidRuntime(390):     at dalvik.system.NativeStart.main(Native Method)

编辑：我添加了 R 文件来验证图像是否被正确引用。

/* AUTO-GENERATED FILE.  DO NOT MODIFY.
 *
 * This class was automatically generated by the
 * aapt tool from the resource data it found.  It
 * should not be modified by hand.
 */

package com.marnbeast.android;

public final class R {
    public static final class attr {
    }
    public static final class drawable {
        public static final int icon=0x7f020000;
        public static final int sample_0=0x7f020001;
        public static final int sample_1=0x7f020002;
        public static final int sample_2=0x7f020003;
        public static final int sample_3=0x7f020004;
        public static final int sample_4=0x7f020005;
        public static final int sample_5=0x7f020006;
        public static final int sample_6=0x7f020007;
        public static final int sample_7=0x7f020008;
    }
    public static final class id {
        public static final int gridview=0x7f050000;
    }
    public static final class layout {
        public static final int main=0x7f030000;
    }
    public static final class string {
        public static final int app_name=0x7f040001;
        public static final int hello=0x7f040000;
    }
}

Answer 1

我们可以使用这段代码，

public class MyGridView extends Activity { 

@Override 
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.animalsgridview);
GridView gridview = (GridView) findViewById(R.id.gridviewid);
gridview.setAdapter(new ImageAdapter(this));
gridview.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
        int imageId = ((ImageAdapter)parent.getAdapter()).mygetItemId(position);

        Intent fullScreenIntent = new Intent(v.getContext(),Full.class);
        fullScreenIntent.putExtra(Full.class.getName(),imageId);
        AnimalsGridView.this.startActivity(fullScreenIntent);         
        }
    });
}
private class ImageAdapter extends BaseAdapter {
    private Context mContext;
    public ImageAdapter(Context c) {
    mContext = c;
    }
    public int getCount() {
        return imagearray.length;
    }
    public Object getItem(int position) {
        return null;
    }
    public long getItemId(int position) {
        return imagearray[position];
    }

    // 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(150, 150));
            imageView.setScaleType(ImageView.ScaleType.FIT_XY);
            imageView.setPadding(1, 1, 1, 1);

        } else {
            imageView = (ImageView) convertView;
        }

        imageView.setImageResource(imagearray[position]);
        return imageView;
    }
    // references to our images                    
    private Integer[] imagearray = {                 

        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7,
        R.drawable.sample_0, R.drawable.sample_1,
        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7,
        R.drawable.sample_0, R.drawable.sample_1,
        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7

        };
    public int mygetItemId(int position) {
                return imagearray[position];
    }                                
  }
}   

这是xml代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_weight="1"
  android:layout_height="fill_parent">
<GridView
    android:id="@+id/gridviewid"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:numColumns="auto_fit"
    android:columnWidth="60dp"
    android:stretchMode="columnWidth"
    android:padding="5dp"
    android:verticalSpacing="5dp"
    android:horizontalSpacing="20dp"        
    android:gravity="center_horizontal"
    android:background="#ffffff"/>    

Answer 2

用给定的代码替换您的适配器类

package com.marnbeast.android; 

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

public class ImageAdapter extends BaseAdapter {
    private Context mContext;

    public ImageAdapter(Context c) {
        mContext = c;
    }

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

    public Object getItem(int position) {
        return mThumbIds[position];
    }

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

    // 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 = {
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7
    };
}

Answer 3

通常，在这些情况下，清理并重建项目即可解决问题。替换图像可能只是强制刷新 R 文件。

如果没有，我唯一的另一个想法是 android 仅支持基线和渐进式 jpeg。如果您的 jpeg 进行了某种奇怪的优化，则可能会导致资源无效。

Answer 4

请尝试清理/重建您的项目