当我将颜色设置为SlidingTabLayout对象时出现错误。 这是我的mainActivity,首先我发现不推荐使用getResource.getColor ..所以我使用了contextCompat.getColor ..但现在它将为null。
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private ViewPager mPager;
private SlidingTabLayout mTabs;
private MyPagerAdapter adapter;
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.app_bar);
mPager = (ViewPager) findViewById(R.id.pager);
mTabs = (SlidingTabLayout) findViewById(R.id.tabs);
setSupportActionBar(toolbar);
assert getSupportActionBar() != null;
getSupportActionBar().setDisplayShowHomeEnabled(true);
NavigationDrawerFragment navigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.fragment_nav_drawer);
navigationDrawerFragment.setUp(R.id.fragment_nav_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), toolbar);
adapter = new MyPagerAdapter(getSupportFragmentManager(),MainActivity.this);
mPager.setAdapter(adapter);
mTabs.setViewPager(mPager);
mTabs.setDistributeEvenly(true);
int bgColor = ContextCompat.getColor(context,R.color.colorAccent);
mTabs.setBackgroundColor(bgColor);
mTabs.setSelectedIndicatorColors(ContextCompat.getColor(context, R.color.colorAccent));
mTabs.invalidate();
mTabs.setCustomTabView(R.layout.custom_tab_view,R.id.tabText);
}
@Deprecated
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Deprecated
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
if (id == R.id.navigate) {
startActivity(new Intent(this, SubActivity.class));
}
return super.onOptionsItemSelected(item);
}
public static class MyFragment extends Fragment {
private TextView textView;
public static MyFragment getInstance(int position) {
MyFragment myFragment = new MyFragment();
Bundle args = new Bundle();
args.putInt("position", position);
myFragment.setArguments(args);
return myFragment;
}
@Override
public View onCreateView(LayoutInflater inflater,@Nullable ViewGroup container, Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.fragment_my, container, false);
textView = (TextView) layout.findViewById(R.id.position);
Bundle bundle = getArguments();
if (bundle != null) {
textView.setText(bundle.getInt("position"));
}
return layout;
}
}
class MyPagerAdapter extends FragmentStatePagerAdapter {
Context mContext;
int icons[] = {R.drawable.home,R.drawable.hot_article,R.drawable.dizzy_person};
String[] tabText = getResources().getStringArray(R.array.tabs);
public MyPagerAdapter(FragmentManager fm,Context context ) {
super(fm);
this.mContext = context;
}
@Override
public Fragment getItem(int position) {
MyFragment myFragment = MyFragment.getInstance(position);
return myFragment;
}
@Override
public CharSequence getPageTitle(int position) {
Drawable drawable = ResourcesCompat.getDrawable(getResources(),icons[position],null);
drawable.setBounds(0, 0, 36, 36);
ImageSpan imageSpan = new ImageSpan(drawable);
SpannableString spannableString = new SpannableString(" ");
spannableString.setSpan(imageSpan,0,spannableString.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
return spannableString;
}
@Override
public int getCount() {
return 3;
}
}
}
棉花糖中是否有任何新方法可以解决这个问题...帮助我..
答案 0 :(得分:10)
这是因为上下文尚未初始化。我建议你不要在那里和那里有Context
的飞行参考。 Activity
是Context的子类。您可以直接使用this
或NameOfActivity.this
来访问上下文。
int bgColor = ContextCompat.getColor(context,R.color.colorAccent);
应该是
int bgColor = ContextCompat.getColor(this ,R.color.colorAccent);
答案 1 :(得分:0)
将context
更改为MainActivity.this
使用这种方式
int bgColor = ContextCompat.getColor(MainActivity.this,R.color.colorAccent);
mTabs.setBackgroundColor(bgColor);
mTabs.setSelectedIndicatorColors(ContextCompat.getColor(MainActivity.this, R.color.colorAccent));
答案 2 :(得分:0)
使用localhost.localdomain
并检查您的上下文是否为null或您的color_name值是否实际存在
答案 3 :(得分:0)
它是一项活动。 所以我们可以使用,
int bgColor = ContextCompat.getColor(MainActivity.this,R.color.colorAccent);
如果是Fragment 我们可以使用,
int bgColor = ContextCompat.getColor(this.getActivity(),R.color.colorAccent);
答案 4 :(得分:0)
如果您尝试基于异步数据库调用修改视图,您可能希望将上下文传递给执行数据库调用的方法 你甚至可以关注this
private void dbCall(Activity activity){
// perform the database call
int bgColor = ContextCompat.getColor(activity,R.color.colorAccent);
}
答案 5 :(得分:0)
您可以通过从视图中获取上下文
来解决此问题testview.setBackgroundColor(ContextCompat.getColor(testview.getContext(), R.color.colorBlack));