我已按照本教程实施了自定义图库：http://vikaskanani.wordpress.com/2011/07/20/android-custom-image-gallery-with-checkbox-in-grid-to-select-multiple/。 它工作正常，但我想稍微修改一下。 例如，当我单击复选框时，它将被选中并选择图像。 但是，如果单击图像，则不会选中该图像，并且不会选中该复选框。 你能帮我理解我怎么修改它？ 这是我正在尝试使用的代码：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.custom_gallery); //assign the layout file to the activity
final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };
final String orderBy = MediaStore.Images.Media._ID;
Cursor imagecursor = managedQuery( //create the cursor for navigate inside the database device and retrieve informations about the media contents like photo, video ecc...
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null,
null, orderBy);
int image_column_index = imagecursor.getColumnIndex(MediaStore.Images.Media._ID); //get the current column index
this.count = imagecursor.getCount(); //count the external content uri of the cursor
this.thumbnails = new Bitmap[this.count]; //create an array of bitmap using the size retrieved from the count variable
this.arrPath = new String[this.count]; //create the array that contains the list of the path of the media (photos in this case)
this.thumbnailsselection = new boolean[this.count]; //initialize the array of boolean to save informations about the selection of the thumbnails
for (int i = 0; i < this.count; i++) {
imagecursor.moveToPosition(i); //let's start from the first position and move one by one until the end
int id = imagecursor.getInt(image_column_index);
int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
thumbnails[i] = MediaStore.Images.Thumbnails.getThumbnail( //take the thumbnails of the images and store it inside the array using the MICRO format for avoid high memory usage
getApplicationContext().getContentResolver(), id,
MediaStore.Images.Thumbnails.MICRO_KIND, null);
arrPath[i]= imagecursor.getString(dataColumnIndex);
}
GridView imagegrid = (GridView) findViewById(R.id.PhoneImageGrid); //assign the GridView to the equivalent element in the xml file
imageAdapter = new ImageAdapter(); //create a new imageAdapter. It is used how source for all the items in the gridView
imagegrid.setAdapter(imageAdapter);
imagecursor.close(); //close the image cursor when we arrive to the end of the columns to analize
final Button selectBtn = (Button) findViewById(R.id.selectBtn); //assign the button to the equivalent in the xml layout
selectBtn.setOnClickListener(new OnClickListener() { //create a listener for reveal when it is pressed
public void onClick(View v) {
// TODO Auto-generated method stub
final int len = thumbnailsselection.length;
int cnt = 0; //initialize a count for check the number of selected photos
String selectImages = "";
for (int i =0; i<len; i++)
{
if (thumbnailsselection[i]){
cnt++;
selectImages = selectImages + arrPath[i] + "|"; //store the correct path of the images in the variable (we can use this string for find the images path in others activity)
}
}
//if no one image is selected show a message to the user
if (cnt == 0){
Toast.makeText(getApplicationContext(),
"Please select at least one image",
Toast.LENGTH_LONG).show();
} else {
//If at least one image is selected we create a new activity where the images are displayed and the user can manage them
Intent photoManagementIntent = new Intent(
getApplicationContext(),
PhotoManagement.class //select the class for the next activity
);
photoManagementIntent.putExtra("Selected Images",""+selectImages); //add an extra parameter that contains the path of the selected images. In this mode we can read it in the next activity
startActivity(photoManagementIntent); //start the new activity
}
}
});
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(
R.layout.gallery_item, null);
holder.imageview = (ImageView) convertView.findViewById(R.id.thumbImage);
holder.checkbox = (CheckBox) convertView.findViewById(R.id.itemCheckBox);
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
holder.checkbox.setId(position);
holder.imageview.setId(position);
holder.checkbox.setOnClickListener(new OnClickListener() { //create a listener for the checkbox for check or uncheck it
public void onClick(View v) {
// TODO Auto-generated method stub
CheckBox cb = (CheckBox) v;
int id = cb.getId();
if (thumbnailsselection[id]){
cb.setChecked(false); //uncheck the checkbox
thumbnailsselection[id] = false;
} else {
cb.setChecked(true); //check the checkbox
thumbnailsselection[id] = true;
}
}
});
holder.imageview.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Log.i("IMAGE","PRESSED");
ImageView iv = (ImageView) v;
CheckBox cb = (CheckBox) v;
int id = iv.getId();
cb.setChecked(thumbnailsselection[id]);
}
});
holder.imageview.setImageBitmap(thumbnails[position]); //set the image in the correct position in the view
holder.checkbox.setChecked(thumbnailsselection[position]); //set the checkbox in the correct position
holder.id = position;
return convertView;
}
}
这是使用我的代码发生的错误：
09-27 15:30:48.895: E/AndroidRuntime(4526): FATAL EXCEPTION: main
09-27 15:30:48.895: E/AndroidRuntime(4526): java.lang.ClassCastException: android.widget.ImageView cannot be cast to android.widget.CheckBox
09-27 15:30:48.895: E/AndroidRuntime(4526): at com.example.dilandprints2.CustomGallery$ImageAdapter$2.onClick(CustomGallery.java:146)
09-27 15:30:48.895: E/AndroidRuntime(4526): at android.view.View.performClick(View.java:4204)
09-27 15:30:48.895: E/AndroidRuntime(4526): at android.view.View$PerformClick.run(View.java:17355)
09-27 15:30:48.895: E/AndroidRuntime(4526): at android.os.Handler.handleCallback(Handler.java:725)
09-27 15:30:48.895: E/AndroidRuntime(4526): at android.os.Handler.dispatchMessage(Handler.java:92)
09-27 15:30:48.895: E/AndroidRuntime(4526): at android.os.Looper.loop(Looper.java:137)
09-27 15:30:48.895: E/AndroidRuntime(4526): at android.app.ActivityThread.main(ActivityThread.java:5041)
09-27 15:30:48.895: E/AndroidRuntime(4526): at java.lang.reflect.Method.invokeNative(Native Method)
09-27 15:30:48.895: E/AndroidRuntime(4526): at java.lang.reflect.Method.invoke(Method.java:511)
09-27 15:30:48.895: E/AndroidRuntime(4526): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
09-27 15:30:48.895: E/AndroidRuntime(4526): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
09-27 15:30:48.895: E/AndroidRuntime(4526): at dalvik.system.NativeStart.main(Native Method)
09-27 15:30:51.446: E/Trace(4545): error opening trace file: No such file or directory (2)
由于
答案 0 :(得分：1)
您应该查看本教程：Android Checkbox Example - Mkyong.com。它向您展示了如何为您的复选框实现onClick侦听器。以下是链接中侦听器的实际代码：
chkIos.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//is chkIos checked?
if (((CheckBox) v).isChecked()) {
Toast.makeText(MyAndroidAppActivity.this,
"Bro, try Android :)", Toast.LENGTH_LONG).show();
}
}
});
答案 1 :(得分：1)
问题在于：
ImageView iv = (ImageView) v;
CheckBox cb = (CheckBox) v;
View如何既是ImageView又是CheckBox？第二行将ImageView强制转换为CheckBox，从而将java.lang.ClassCastException抛出到logcat中。
您需要获取与ImageView关联的CheckBox的引用。
这样做的一种可能方法是使用View的父级，如下所示：
LinearLayout row = (LinearLayout) v.getParent();
CheckBox cb = (CheckBox) row.findViewById(R.id.itemCheckBox);