我是 Android 开发的新手，我可以使用一些帮助！
我正在尝试创建一个 GridView 以显示 1 张使用不同过滤器加载 9 次的图像。我正在使用适用于 Android 的 GPUImage 框架和通用图像加载器。
这是我到目前为止所拥有的：
public class FilterActivity extends Activity {
private MyApplication mApp;
private ArrayList<GPUImageFilter>filters;
public ArrayList<Bitmap>bitmaps;
private List<String> filterNames;
int maxWidth = 120;
int maxHeight = 120;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_filter);
Uri imageURI = mApp.getFirstImagePath();
ImageLoader imageLoader = ImageLoader.getInstance();
BitmapFactory.Options resizeOptions = new BitmapFactory.Options();
resizeOptions.inSampleSize = 3; // decrease size 3 times
resizeOptions.inScaled = true;
DisplayImageOptions options = new DisplayImageOptions.Builder()
.cacheOnDisk(true)
.considerExifParams(true)
.bitmapConfig(Bitmap.Config.RGB_565)
.decodingOptions(resizeOptions)
.postProcessor(new BitmapProcessor() {
@Override
public Bitmap process(Bitmap bmp) {
return scaleBitmap(bmp);
}
})
.build();
Bitmap bmp = imageLoader.loadImageSync(imageURI.toString(), options);
filterNames = Arrays.asList("grayscale", "documentary", "sepia",
"posterize", "noFilter", "lomo",
"cool", "warm", "vignette");
for (String filterName : filterNames ){
filters.add(filterWithName(filterName));
}
GPUImage mGPUImage = new GPUImage(this);
mGPUImage.getBitmapForMultipleFilters(bmp,filters, new GPUImage.ResponseListener<Bitmap>() {
@Override
public void response(Bitmap bitmap) {
bitmaps.add(bitmap);
}
});
GridView gridView = (GridView) findViewById(R.id.gridViewFX);
gridView.setAdapter(new ImageAdapter(this));
gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
});
}
private Bitmap scaleBitmap(Bitmap bm) {
int width = bm.getWidth();
int height = bm.getHeight();
Log.v("Pictures", "Width and height are " + width + "--" + height);
if (width > height) {
// landscape
float ratio = (float) width / maxWidth;
width = maxWidth;
height = (int)(height / ratio);
} else if (height > width) {
// portrait
float ratio = (float) height / maxHeight;
height = maxHeight;
width = (int)(width / ratio);
} else {
// square
height = maxHeight;
width = maxWidth;
}
Log.v("Pictures", "after scaling Width and height are " + width + "--" + height);
bm = Bitmap.createScaledBitmap(bm, width, height, true);
return bm;
}
private GPUImageFilter filterWithName(String name) {
GPUImageFilter mGPUImageFilter;
switch (name) {
default:
case "noFilter":
mGPUImageFilter = new GPUImageContrastFilter(.5f);
break;
case "grayscale":
mGPUImageFilter = new GPUImageGrayscaleFilter();
break;
case "documentary":
float[] color = new float[]{1.f, 1.f, 1.f, 1.f};
mGPUImageFilter = new GPUImageMonochromeFilter(.8f, color);
break;
case "sepia":
mGPUImageFilter = new GPUImageSepiaFilter(.85f);
break;
case "posterize":
mGPUImageFilter = new GPUImagePosterizeFilter();
break;
case "lomo":
mGPUImageFilter = new GPUImagePixelationFilter();
break;
case "cool":
GPUImageLookupFilter amatorka = new GPUImageLookupFilter();
amatorka.setBitmap(BitmapFactory.decodeResource(this.getResources(), R.drawable.lookup_amatorka));
mGPUImageFilter = amatorka;
break;
case "warm":
mGPUImageFilter = new GPUImageCrosshatchFilter();
break;
case "vignette":
PointF centerPoint = new PointF();
centerPoint.x = 0.5f;
centerPoint.y = 0.5f;
mGPUImageFilter = new GPUImageVignetteFilter(centerPoint, new float[]{0.0f, 0.0f, 0.0f, 0.0f}, 0.3f, 0.75f);
break;
}
return mGPUImageFilter;
}
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return bitmaps.size();
}
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.setImageBitmap(bitmaps.get(position));
return imageView;
}
}
}
和xml：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.example.andreaskaitis.myapplication.FilterActivity">
android:background="@drawable/background">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/layoutX">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="75dp"
android:text="@string/effects"
android:layout_gravity="center_horizontal"
android:textColorHint="#ffffffff"
android:textColor="#ffffffff"
android:shadowColor="#000000"
android:shadowDx="1"
android:shadowDy="1"
android:shadowRadius="2"
/>
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="5dp"
android:layout_marginBottom="50dp"
android:background="@drawable/layout_bg"
android:alpha="1"
android:id="@+id/roundedLayout">
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridViewFX"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:horizontalSpacing="4dip"
android:numColumns="3"
android:stretchMode="columnWidth"
android:verticalSpacing="4dip"
android:padding="4dip" />
</LinearLayout>
</LinearLayout>
当我尝试编译时，我得到了这个：
04-07 04:36:12.453 1527-1527/com.example.andreaskaitis.myapplication I/Choreographer﹕ Skipped 37 frames! The application may be doing too much work on its main thread.
04-07 04:36:12.485 1527-1565/com.example.andreaskaitis.myapplication W/dalvikvm﹕ threadid=22: thread exiting with uncaught exception (group=0xa4c40648)
04-07 04:36:12.485 1527-1565/com.example.andreaskaitis.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: GLThread 119
java.lang.NullPointerException
at jp.co.cyberagent.android.gpuimage.GPUImageRenderer$3.run(GPUImageRenderer.java:184)
at jp.co.cyberagent.android.gpuimage.GPUImageRenderer.runAll(GPUImageRenderer.java:126)
at jp.co.cyberagent.android.gpuimage.GPUImageRenderer.onDrawFrame(GPUImageRenderer.java:115)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1523)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1240)
任何关于指出我做错了什么以及如何解决它的帮助将不胜感激！