我正在开发一个应用程序,它使用 ViewPager
和两个滑动 View (first_page.xml 和 second_page.xml)并且有一个 Activity (activity_main.xml)。
在主 Activity 类中时,我尝试使用 TextView
访问 findViewById
(位于 first_page.xml 中),但找不到它。
这是我的activity_main.xml
<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" >
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</RelativeLayout>
这是我的 first_page.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/someText"
android:text="example"
android:textSize="42sp" >
</TextView>
</LinearLayout>
这是我的 customPagerAdapter
public class CustomPagerAdapter extends PagerAdapter {
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.first_page;
break;
}
case 1: {
resId = R.layout.second_page;
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;
}
@Override
public int getCount() {
return 2;
}
}
这是我的
MainActivity
,我想在其中获取 first_page 布局,找到名为 someText 的 TextView
,并设置新的自定义字体。public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create and set adapter
CustomPagerAdapter adapter = new CustomPagerAdapter();
ViewPager myPager = (ViewPager) findViewById(R.id.pager);
myPager.setAdapter(adapter);
myPager.setCurrentItem(0);
/*
* Here i want to set a new custom font but it seems the someText can't
* be found because the Activity searches for it in the
* layout.activity_main and not in the layout.first_page
*/
TextView textView = (TextView) findViewById(R.id.someText);
Typeface font = Typeface.createFromAsset(getAssets(), "roboto_thin.ttf");
textView.setTypeface(font);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
我在这个问题上挣扎了两天。
有什么建议么?
最佳答案
textview被封装在fragment的容器中。如果您获得对正确 fragment 的引用并获得对容器的引用,您可以调用 findViewById(R.id.someid)。
示例代码:
// TODO cast checks
int item = mViewPager.getCurrentItem();
Fragment frag = (Fragment) mPagerAdapter.getItem(item);
View container = frag.getView();
TextView searchTextView = (TextView) container.findViewById(R.id.someid);
或者是你的情况:
// TODO add null + cast checks
TextView textView = (TextView) ((Fragment)adapter.getItem(0)).getView().findViewById(R.id.someText);
关于android - 从 MainActivity 获取 ViewPager View ,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/20840925/