Android Hello GridView 教程不会显示图像

标签 android android-layout textview android-gridview

第一次发海报!

我是 Android 开发的新手，一直在关注 Google 的 HelloView 教程，没有问题......直到 HelloGridView 教程。出于某种原因，我无法显示任何图像，只有黑色背景。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 代码并缩小我可能出现的问题区域来消除一些额外的复杂性。我的代码与提供的代码完全相同，直接复制粘贴。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 代码似乎已经成功识别它们并相应地更新了它生成的代码。我正在使用 Android 目标 1.5，并且在我的 Droid X 和使用 Android 模拟器上都尝试过这个程序。我有我所有的导入，代码编译并运行良好。但是，我的 Activity 仅显示黑屏；没有图像出现。当我点击黑色背景时，橙色方块出现在图像应该出现的位置。我发现一两个帖子提到了这个问题，但它总是伴随着一些更大、更明显的问题，而且从未得到解决。我将在下面列出我的代码和 LogCat 以供引用。

我注意到我的 LogCat 提到:

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

这让我想到了这个话题:
Why setImageResource displays nothing?
详细说明使用 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]));

然而，这只是导致 Resources$NotFoundException 崩溃了我的代码(也在下面记录)。

结语
我认为 Android 教程不需要解决方法，所以我猜我有某种配置问题。经过几个小时的搜索和尝试，我还没有找到解决方案，所以我认为值得讨论一下。另外，这是我的第一篇文章，如果您看到任何明显的失礼，请告诉我。我提前为即将到来的墙代码道歉，尽管我认为数据太少可能比太多更糟糕。 :D

谢谢你们!

猛兽

更新
我尝试在我的 mThumbIds 中使用 R.drawable.icon，在它和我的一张照片之间交替。没有任何图片出现，但图标出现了。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 图像并在油漆中对其进行了编辑(在 android 人上留了一个 mustache :D)并将其保存为 dummyicon.png。我在那个和图标之间交替，但这也不起作用。最后，我去掉了所有的图标引用，只使用了我的 png 图像，但奇怪的是，当运行时，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，当时什么都不显示。我更改了一些 dummyicon，当运行时，这些图像没有显示/只是黑色。所有其他图像(在 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 icon 替换了我转换后的 png 图像引用，在 icon 和 dummyicon 之间交替，现在它们都没有出现 - 只是再次出现黑屏。所以看起来 dummyicon 和 icon 在引用时都没有产生任何东西，只是一个黑色的空间，但是我转换的 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:

Emulator Display - GridView Problem

解决方案!
事实证明，出于某种原因，本教程不适用于处理 JPEG 图像的我。此外，我做了一个愚蠢的假设，只是将扩展名从 .jpg 更改为 .png，它仍然可以在图像查看器中使用，但仍然被 android 识别为 jpg。现在我已经用油漆编辑了每张图片，然后保存为 PNG 类型，一切似乎都正常。

但是我仍然觉得这里有一个问题。我假设 android 应该处理 .jpg 图像，因为他们提供 jpegs 作为他们的示例图片。如果有人知道为什么 PNG 可以工作而 JPG 不行，请回复。同时，这个简单的修复会很好。

感谢您的帮助!

引用

主文件:
<?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));

    }
}

图像适配器
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 无法找到资源:
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 变通后，LogCat Resource Not Fount 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:我包含了 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;
    }
}

最佳答案

我们可以使用这个代码，

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"/>

关于Android Hello GridView 教程不会显示图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6805541/

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