问题描述
如题， 我想通过点击gridview下的item而更改他的imageview。 不过点击了没有反应。 有没有大神知道怎么回事？
public class table extends AppCompatActivity implements AdapterView.OnItemClickListener{GridView gridView;my_adapter my_adapter;String table_names[]={'1a','1b','1c','1d','2a','2b','2c','2d','3a','3b','3c','3d'};@Overrideprotected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_table); gridView=(GridView)findViewById(R.id.gridview); my_adapter=new my_adapter(this,table_names); gridView.setAdapter(my_adapter); gridView.setOnItemClickListener(this);}@Overridepublic void onItemClick(final AdapterView<?> adapterView, final View view, final int i, long l) { new AlertDialog.Builder(this) .setTitle('Table number: '+adapterView.getItemAtPosition(i).toString()) .setMessage('Open Table？') .setPositiveButton('Yes', new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { my_adapter.change_img(); // 更换新的图片} }) .setNegativeButton('No', new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { my_adapter.change_img2(); // 更换回原来的图片} }) .show();}}class my_adapter extends BaseAdapter{ImageView imageView;LayoutInflater inflater=null;Context ctx;String table_names[];ArrayList store_table_no;my_adapter(Context ctx, String table_names[]){ this.ctx=ctx; this.table_names=table_names; store_table_no=new ArrayList<Integer>(); for (int i=0;i<table_names.length;i++){store_table_no.add(table_names[i]); }}@Overridepublic int getCount() { return store_table_no.size();}@Overridepublic Object getItem(int i) { return store_table_no.get(i);}@Overridepublic long getItemId(int i) { return i;}@Overridepublic View getView(int i, View view, ViewGroup viewGroup) { View row=view; if(row==null){inflater=(LayoutInflater)ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);row=inflater.inflate(R.layout.single,null); } TextView tv_table_no=(TextView)row.findViewById(R.id.table_no); imageView=(ImageView)row.findViewById(R.id.imageView); tv_table_no.setText(''+store_table_no.get(i)); return row;}public void change_img(){ imageView.setImageResource(R.drawable.table_full);}public void change_img2(){ imageView.setImageResource(R.drawable.table3d2);}}
single.xml
<?xml version='1.0' encoding='utf-8'?><RelativeLayout xmlns:android='http://schemas.android.com/apk/res/android'xmlns:app='http://schemas.android.com/apk/res-auto'xmlns:tools='http://schemas.android.com/tools'android:orientation='vertical' android:layout_width='match_parent'android:layout_height='match_parent'><TextView android:text='101' android:layout_width='wrap_content' android:layout_height='wrap_content' android: android:layout_centerHorizontal='true' android:layout_centerVertical='true' android:textSize='22sp' /><ImageView app:srcCompat='@drawable/table' android: android:layout_centerHorizontal='true' android:layout_centerVertical='true' android:layout_width='130dp' android:layout_height='100dp' /></RelativeLayout>
问题解答
回答1：public void change_img(){ imageView.setImageResource(R.drawable.table_full);}public void change_img2(){ imageView.setImageResource(R.drawable.table3d2);}
你这两个方法里面的imageView不是当前item对应的ImageView
正确的做法应该是在
@Overridepublic void onItemClick(final AdapterView<?> adapterView, final View view, final int i, long l) { // 找到被点击的item中的iamgeView final View imageView = view.findViewById(R.id.imageView); new AlertDialog.Builder(this) .setTitle('Table number: '+adapterView.getItemAtPosition(i).toString()) .setMessage('Open Table？') .setPositiveButton('Yes', new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { if(imageView != null && (imageView instanceOf ImageView)) {// 检查防止报错((ImageView)imageView).setImageResource(R.drawable.table_full); }} }) .setNegativeButton('No', new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) { //同上} }) .show(); }}
