我有一个简单的应用程序,在 activity_main 中有1个GridView和1个按钮。 当我点击Button时,我想稍微增加每个项目(在GridView中)的尺寸。 但它不起作用。所以任何人都帮助我...
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<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"
tools:context=".MainActivity">
<GridView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:numColumns="4"
android:id="@+id/gridView"
>
</GridView>
<Button
android:id="@+id/btnSize"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/gridView"
android:layout_centerHorizontal="true"
android:text="Increase Size"
/>
</RelativeLayout>
custom_gridview_item.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="@+id/imageView"
android:layout_width="100dp"
android:layout_height="100dp"
android:scaleType="centerCrop"
/>
</LinearLayout>
MainActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().hide();
setContentView(R.layout.activity_main);
gridView = (GridView) findViewById(R.id.gridView);
customBaseAdapter = new CustomBaseAdapter(this, R.layout.custom_gridview_item, imageIDs);
customBaseAdapter.notifyDataSetChanged();
gridView.setAdapter(customBaseAdapter);
btnIncrease = (Button) findViewById(R.id.btnSize);
btnIncrease.setOnClickListener(this);
}
@Override
public void onClick(View v) {
customBaseAdapter.changeLayout(customBaseAdapter.getWidth() + 40, customBaseAdapter.getHeight() + 40);
customBaseAdapter.notifyDataSetChanged();
gridView.invalidateViews();
}
CustomBaseAdapter.java
public class CustomBaseAdapter extends BaseAdapter{
Context context;
int layout;
int[] imageIDS;
int Height = 300;
int Width = 300;
public static class ViewHolder
{
ImageView imgView;
}
public int getHeight() {
return Height;
}
public int getWidth() {
return Width;
}
public CustomBaseAdapter(Context context, int layout, int[] imageIDS) {
this.context = context;
this.layout = layout;
this.imageIDS = imageIDS;
}
@Override
public int getCount() {
return imageIDS.length;
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View viewrow = convertView;
if (viewrow == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
viewrow = inflater.inflate(layout, parent, false);
ViewHolder holder = new ViewHolder();
holder.imgView = (ImageView) viewrow.findViewById(R.id.imageView);
ViewGroup.LayoutParams layoutParams = holder.imgView.getLayoutParams();
layoutParams.width = Width;
layoutParams.height = Height;
holder.imgView.requestLayout();
viewrow.setTag(holder);
}
ViewHolder holder = (ViewHolder) viewrow.getTag();
holder.imgView.setImageResource(imageIDS[position]);
return viewrow;
}
public void changeLayout(int width, int height){
Width = width;
Height = height;
}