Dưới đây là cách bố trí hoạt động chính XMLViewPager không nhìn thấy được khi nó có bất kỳ cách bố trí khác như người anh em của nó
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="fill_parent">
<LinearLayout
android:id="@+id/left"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
<android.support.v4.view.ViewPager
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="0dip"
android:layout_height="fill_parent"
android:layout_toLeftOf="@+id/left"
android:layout_toRightOf="@+id/right"
tools:context=".MainActivity" />
<LinearLayout
android:id="@+id/right"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentRight="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
</RelativeLayout>
Fragment Layout XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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" android:orientation="horizontal"
tools:context=".DummySectionFragment" android:background="@color/gray">
<TextView
android:id="@+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
Hoạt động chính:
package com.example.androidtest;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.view.Menu;
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager(), getApplicationContext());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager
.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@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;
}
@Override
public void onTabSelected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
}
Fragment :
package com.example.androidtest;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.TextView;
/**
* A dummy fragment representing a section of the app, but that simply
* displays dummy text.
*/
public class DummySectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy,
container, false);
TextView dummyTextView = (TextView) rootView
.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(
ARG_SECTION_NUMBER)));
return rootView;
}
}
Pager Adaptor:
package com.example.androidtest;
import java.util.Locale;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
private Context context;
public SectionsPagerAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = new DummySectionFragment();
Bundle args = new Bundle();
args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
fragment.setArguments(args);
return fragment;
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return context.getString(R.string.title_section1).toUpperCase(l);
case 1:
return context.getString(R.string.title_section2).toUpperCase(l);
case 2:
return context.getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
dự kiến: 2 quầy bar màu đỏ ở hai bên. ViewPager ở giữa.
Điều gì xảy ra: 2 thanh màu đỏ ở cả hai bên. Trống ở giữa.
Câu hỏi: Tại sao?
EDIT:
tôi sửa đổi cách bố trí hoạt động chính XML như sau để có được điều này để làm việc.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="fill_parent">
<LinearLayout
android:id="@+id/left"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentLeft="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
<android.support.v4.view.ViewPager
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
tools:context=".MainActivity" android:layout_toRightOf="@+id/left"/>
<LinearLayout
android:id="@+id/right"
android:layout_width="100dp"
android:layout_height="fill_parent"
android:layout_alignParentRight="true"
android:background="@color/red"
android:orientation="horizontal" >
</LinearLayout>
</RelativeLayout>
Chỉ thay đổi là tôi đã xóa android:layout_toRightOf="@+id/right"
và thay đổi layout_width = "fill_parent". Fill_parent Tôi hiểu. Tại sao việc loại bỏ người kia tạo nên sự khác biệt?
Có. Cách tiếp cận này cũng hoạt động. Tuy nhiên, tôi đã sửa đổi XML hoạt động chính và nó hoạt động. Chỉ có điều tôi loại bỏ layout_toRightOf và thêm chiều rộng như fill_parent. – Prabhat