我的代码的作用:
这是我的代码,用于在 xml 布局(名为 left.xml、right.xml 和 center.xml)之间滑动的 viewpager。
我想要它做什么
我想在图像之间滑动(存储在可绘制文件夹中)。当我用 R.drawable.image 替换 R.layout.xml 时,我的应用程序崩溃了。有人能帮我弄清楚吗?
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MyPagerAdapter adapter = new MyPagerAdapter();
ViewPager myPager = (ViewPager) findViewById(R.id.myfivepanelpager);
myPager.setAdapter(adapter);
myPager.setCurrentItem(0);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
class MyPagerAdapter extends PagerAdapter {
public int getCount() {
return 3;
}
public Object instantiateItem(View collection, int position) {
LayoutInflater inflater = (LayoutInflater) collection.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
int resId = 0;
switch (position) {
case 0:
resId = R.layout.left;
break;
case 1:
resId = R.layout.center;
break;
case 2:
resId = R.layout.right;
break;
}
View view = inflater.inflate(resId, null);
((ViewPager) collection).addView(view, 0);
return view;
}
@Override
public void destroyItem(View arg0, int arg1, Object arg2) {
((ViewPager) arg0).removeView((View) arg2);
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == ((View) arg1);
}
@Override
public Parcelable saveState() {
return null;
}
}
}
如果您使用相同的实现并只是添加R.drawable.XXX
代替R.layout.YYY
那么问题就在那里。您正在使用LayoutInflater
充气ImageView
s,布局充气器,因为它本身就说明它会在一次中充气整个布局View
.
而不是这样做尝试创建ImageView
对象通过代码,然后在return
返回新创建的ImageView
。一些示例代码是:
public Object instantiateItem(View collection, int position) {
ImageView img = new ImageView(context); //this is a variable that stores the context of the activity
//set properties for the image like width, height, gravity etc...
int resId = 0;
switch (position) {
case 0:
resId = R.drawable.img1;
break;
case 1:
resId = R.drawable.img2;
break;
case 2:
resId = R.drawable.img3;
break;
}
img.setImageResource(resId); //setting the source of the image
return img;
}
如果您只使用特定数量的图像或页面,您应该考虑将它们添加到包含以下内容的 xml 中:ViewPager
而不是动态创建ViewPager
.
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