Android 如何刷新GridView?
我有一个GridView,它与Google教程非常相似,只是我想在运行时添加ImageView(通过子活动)。结果是可以的,但是视图的布局是混乱的:GridView没有填充其父视图的内容,我该怎么做才能正确地设计它 下面是添加子项的代码:Android 如何刷新GridView?,android,xml,gridview,layout,Android,Xml,Gridview,Layout,我有一个GridView,它与Google教程非常相似,只是我想在运行时添加ImageView(通过子活动)。结果是可以的,但是视图的布局是混乱的:GridView没有填充其父视图的内容,我该怎么做才能正确地设计它 下面是添加子项的代码: public void initializeWorkbench(GridView gv, Vector<String> items) { Prototype.workbench.setDimension(screenWidth, d
public void initializeWorkbench(GridView gv, Vector<String> items) {
Prototype.workbench.setDimension(screenWidth, divider.height()+workbenchArea.height());
Prototype.workbench.activateWorkbench();
// this measures the workbench correctly
Log.d(Prototype.TAG, "workbench width: "+Prototype.workbench.getMeasuredWidth());
// 320
Log.d(Prototype.TAG, "workbench height: "+Prototype.workbench.getMeasuredHeight());
// 30
ImageAdapter imgAdapter = new ImageAdapter(this.getContext(), items);
gv.setAdapter(imgAdapter);
gv.measure(screenWidth, screenHeight);
gv.requestLayout();
gv.forceLayout();
Log.d(Prototype.TAG, "gv width: "+gv.getMeasuredWidth());
// 22
Log.d(Prototype.TAG, "gv height: "+gv.getMeasuredHeight());
// 119
Prototype.workbench.setDimension(screenWidth, divider.height()+workbenchArea.height());
}
}
public void initializeWorkbench(GridView gv,向量项){
Prototype.workbench.setDimension(屏幕宽度、分隔器.height()+工作台harea.height());
Prototype.workbench.activateWorkbench();
//这可以正确地测量工作台
Log.d(Prototype.TAG,“工作台宽度:+Prototype.workbench.getMeasuredWidth());
// 320
Log.d(Prototype.TAG,“workbench height:+Prototype.workbench.getMeasuredHeight());
// 30
ImageAdapter imgAdapter=新的ImageAdapter(this.getContext(),items);
gv.设置适配器(imgAdapter);
gv.测量(屏幕宽度、屏幕高度);
gv.requestLayout();
gv.forceLayout();
Log.d(Prototype.TAG,“gv-width:+gv.getMeasuredWidth());
// 22
Log.d(Prototype.TAG,“gv高度:+gv.getMeasuredHeight());
// 119
Prototype.workbench.setDimension(屏幕宽度、分隔器.height()+工作台harea.height());
}
}
激活工作台,在工作台中设置尺寸和测量(网格视图上方的线性布局):
public void activateWorkbench(){
if(this.equals(Prototype.workbench)){
此设置方向(垂直);
show=true;
度量();
}
}
公共void setDimension(int w,int h){
宽度=w;
高度=h;
this.setLayoutParams(新的LinearLayout.LayoutParams(宽度、高度));
这个。使无效();
}
私人无效措施(){
if(this.getOrientation()==LinearLayout.VERTICAL){
int h=0;
int w=0;
这是被测儿童(0,0);
for(int i=0;i
ImageAdapter构造函数:
public ImageAdapter(Context c, Vector<String> items) {
mContext = c;
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// We can read and write the media
mExternalStorageAvailable = mExternalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// We can only read the media
mExternalStorageAvailable = true;
mExternalStorageWriteable = false;
} else {
// Something else is wrong. It may be one of many other states, but
// all we need
// to know is we can neither read nor write
mExternalStorageAvailable = mExternalStorageWriteable = false;
}
if (mExternalStorageAvailable && mExternalStorageWriteable) {
for (String item : items) {
File f = new File(item);
if (f.exists()) {
try {
FileInputStream fis = new FileInputStream(f);
Bitmap b = BitmapFactory.decodeStream(fis);
bitmaps.add(b);
files.add(f);
} catch (FileNotFoundException e) {
Log.e(Prototype.TAG, "", e);
}
}
}
}
}
公共ImageAdapter(上下文c、向量项){
mContext=c;
布尔值mExternalStorageAvailable=false;
布尔值mExternalStorageWriteable=false;
String state=Environment.getExternalStorageState();
if(环境、介质、安装等于(状态)){
//我们可以读写媒体
mExternalStorageAvailable=mExternalStorageWriteable=true;
}else if(Environment.MEDIA\u MOUNTED\u READ\u ONLY.equals(state)){
//我们只能阅读媒体
mExternalStorageAvailable=true;
mExternalStorageWriteable=false;
}否则{
//还有一些问题。它可能是许多其他州中的一个,但是
//我们所需要的
//要知道,我们既不会读也不会写
mExternalStorageAvailable=mExternalStorageWriteable=false;
}
if(mExternalStorageAvailable&&mExternalStorageWriteable){
用于(字符串项:项){
文件f=新文件(项目);
如果(f.exists()){
试一试{
FileInputStream fis=新的FileInputStream(f);
位图b=BitmapFactory.decodeStream(fis);
位图。添加(b);
添加(f);
}catch(filenotfounde异常){
Log.e(Prototype.TAG,”,e);
}
}
}
}
}
以及xml布局:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:gravity="bottom"
android:paddingLeft="0px"
android:paddingTop="0px"
android:paddingRight="0px">
<com.unimelb.pt3.ui.TransparentPanel
android:id="@+id/workbench"
android:layout_width="fill_parent"
android:layout_height="10px"
android:paddingTop="0px"
android:paddingLeft="0px"
android:paddingBottom="0px"
android:paddingRight="0px">
<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" />
</com.unimelb.pt3.ui.TransparentPanel>
</LinearLayout>
您正在将
GridView
放置在com.unimelb.pt3.ui.TransparentPanel
内部,它是10px
高
- 你不应该使用
,你应该使用px
dp
- 将
com.unimelb.pt3.ui.TransparentPanel的
更改为android:layout\u height=“10px”
android:layout\u height=“fill\u parent”
我认为这就是您需要的:)您必须首先告诉适配器通知数据已更改,然后再次将适配器设置为网格
adapter.notifyDataChanged();
grid.setAdapter(adapter);
@斯纳格内弗飞人
你们两个一起得到了。应该是:
adapter.notifyDataChanged();
grid.invalidateViews();
这将标记适配器其数据已更改,然后在调用invalidateViews()方法后将其传播到网格
很高兴我发现了这个问题,因为我不知道如何在网格渲染后将项目添加到网格中。这可能会有所帮助。
在对项目执行删除操作后,我刷新书籍图像缩略图的网格视图。
使用adapter.notifyDataChanged();如上所述,它在我的适配器中被称为不适用于我
//this is a call that retrieves cached data.
//your constructor can be designed and used without it.
final Object data = getLastNonConfigurationInstance();
我基本上只是重新加载适配器并将其绑定到同一个视图
//reload the adapter
adapter = new BooksAdapter(MyBooks.this, MyBooks.this, data, show_collection );
grid.invalidateViews();
grid.setAdapter(adapter);
这些答案实际上都不适用于我,我不得不把它们全部混合在一起。要实际更新GridView,需要执行以下操作:
adapter.notifyDataChanged();
grid.invalidateViews();
grid.setAdapter(adapter);
希望这能帮助那些无法使用其他解决方案的人。在适配器中:
class MAdapter extends BaseAdapter{
List<Objects> mObjects;
...
public void clearAdapter(){
mObjects.clear();
}
public void addNewValues(List<Objects> mObjects){
this.mObjects = mObjects;
}
...
}
adapter.clearAdapter(); // clear old values
adapter.addNewValues(MObjects);
adapter.notifyDataChanged();
class MAdapter扩展了BaseAdapter{
列出移动对象;
...
公共无效clearAdapter(){
mObjects.clear();
}
public void addNewValues(列出移动对象){
this.mObjects=mObjects;
}
...
}
adapter.clearAdapter();//清除旧价值观
adapter.addNewValues(MObjects);
adapter.notifyDataChanged();
可能仅仅因为适配器的数据过时而无法工作(例如,如果活动或片段未被销毁并且一直位于后堆栈中)
所以,如果首先刷新数据,那么之后它就会工作。您应该
class MAdapter extends BaseAdapter{
List<Objects> mObjects;
...
public void clearAdapter(){
mObjects.clear();
}
public void addNewValues(List<Objects> mObjects){
this.mObjects = mObjects;
}
...
}
adapter.clearAdapter(); // clear old values
adapter.addNewValues(MObjects);
adapter.notifyDataChanged();
adapter.notifyDataChanged();