我看过很多关于这个问题的帖子,但我无法弄清楚我的代码。我创建了一个选项卡式活动并在底部设置了三个按钮。按钮在不同片段之间切换。MainActivity 中的按钮打开此选项卡式活动,但问题是片段布局为空(见下图)。
这些按钮工作正常,并将我发送到正确的片段,但当它打开时,没有加载任何片段。
我按照 YouTube 教程构建的代码如下所示:
TabbedActivity.class
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
public class TabbedActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabbed_activity);
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction transaction = fragmentManager.beginTransaction();
int intentFragment = getIntent().getExtras().getInt("frgToLoad");
switch (item.getItemId()) {
case R.id.navigation_home:
transaction.replace(R.id.content,new Fragment_B1()).commit();
/* mTextMessage.setText(R.string.title_home);*/
return true;
case …
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