我在使用支持库时遇到了一个奇怪的问题。
我想在 2.3.3 平台上制作一个带有片段切换的动态导航选项卡，就像API Demo.
在 2.3.3 平台上一切正常，但是当我查看 4.3 平台上的相同活动时，我发现有些奇怪。
无法分离片段，SupportFragmentManagement似乎选项卡选择回调没有正确执行；
以下图片显示了我的演示如何进行
这是我的代码：
package net.zengweizhi.android.gettingstarted.lesson05.test;
import net.zengweizhi.android.gettingstarted.R;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
// 使用支持库中的 api
import android.support.v4.app.Fragment; import android.support.v4.app.FragmentTransaction; import android.support.v7.app.ActionBar; import android.support.v7.app.ActionBar.Tab; import android.support.v7.app.ActionBar.TabListener; import android.support.v7.app.ActionBarActivity;
public class NavigationTabsWithFragmentsV9 extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_navigation_tabs, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.actionButton_addTab:
addTab();
break;
case R.id.actionButton_removeTab:
removeTab();
break;
default:
break;
}
return super.onOptionsItemSelected(item);
}
private int mTabSeq = 0;
private void addTab(){
getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mTabSeq++;
Tab tab = getSupportActionBar().newTab();
tab.setText("TAB " + mTabSeq);
tab.setTabListener(new MyTabListener(this));
getSupportActionBar().addTab(tab);
}
private void removeTab(){
Tab tab = getSupportActionBar().getSelectedTab();
getSupportActionBar().removeTab(tab);
Fragment fragment = getSupportFragmentManager().findFragmentByTag(tab.getText().toString());
getSupportFragmentManager().beginTransaction().remove(fragment).commit();
if( getSupportActionBar().getTabCount() == 0 ){
getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
}
}
private static final class MyTabListener implements TabListener {
private NavigationTabsWithFragmentsV9 mActivity;
public MyTabListener(NavigationTabsWithFragmentsV9 activity /*,Fragment fragment*/){
mActivity = activity;
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// Do nothing
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Object obj = tab.getTag();
if( null == obj ){
Bundle args = new Bundle();
args.putString(SimpleFragment.EXTRA_OUTPUT_MESSAGE, tab.getText().toString());
Fragment fragment = Fragment.instantiate(mActivity, SimpleFragment.class.getName(), args);
ft.add(android.R.id.content, fragment, tab.getText().toString());
tab.setTag(obj = fragment);
}
ft.attach((Fragment)obj);
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if( null != mActivity.getSupportFragmentManager().findFragmentByTag(tab.getText().toString()) ){
ft.detach((Fragment)tab.getTag());
}
}
}
public static final class SimpleFragment extends Fragment {
public static final String EXTRA_OUTPUT_MESSAGE = "output_message";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View fragmentView = inflater.inflate(R.layout.fragment_simple, container, false);
String outputMesasge = null;
if( null != getArguments() ){
outputMesasge = getArguments().getString(EXTRA_OUTPUT_MESSAGE);
}
if( null == outputMesasge || 0 == outputMesasge.trim().length() ){
outputMesasge = getString(R.string.demo_text);
}
TextView textView = (TextView) fragmentView.findViewById(R.id.textView_simpleFragmentOutput);
textView.setText(outputMesasge);
return fragmentView;
}
}
}
但是当我全部更改support api为 时regular api(default platform api)，在 4.3 平台上一切正常（但这个与 2.3.3 平台不兼容）；
这是代码（除了 ActionBar 和 Fragment API 没有区别）
package net.zengweizhi.android.gettingstarted.lesson05.test;
import net.zengweizhi.android.gettingstarted.R;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
// 使用默认平台的 api（仅在 v11 及更高版本中）
import android.annotation.SuppressLint;
import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.ActionBar.TabListener;
import android.app.Fragment;
import android.app.FragmentTransaction;
@SuppressLint("NewApi")
public class NavigationTabsWithFragmentsV14 extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_navigation_tabs, menu);
return super.onCreateOptionsMenu(menu);
}
private int mTabSeq = 0;
private void addTab(){
getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mTabSeq++;
Tab tab = getActionBar().newTab();
tab.setText("TAB " + mTabSeq);
tab.setTabListener(new MyTabListener(this));
getActionBar().addTab(tab);
}
private void removeTab(){
Tab tab = getActionBar().getSelectedTab();
getActionBar().removeTab(tab);
Fragment fragment = getFragmentManager().findFragmentByTag(tab.getText().toString());
getFragmentManager().beginTransaction().remove(fragment).commit();
if( getActionBar().getTabCount() == 0 ){
getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.actionButton_addTab:
addTab();
break;
case R.id.actionButton_removeTab:
removeTab();
break;
default:
break;
}
return super.onOptionsItemSelected(item);
}
private static final class MyTabListener implements TabListener {
private NavigationTabsWithFragmentsV14 mActivity;
public MyTabListener(NavigationTabsWithFragmentsV14 activity /*,Fragment fragment*/){
mActivity = activity;
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// Do nothing
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Object obj = tab.getTag();
if( null == obj ){ // initialize fragment to tab
Bundle args = new Bundle();
args.putString(SimpleFragment.EXTRA_OUTPUT_MESSAGE, tab.getText().toString());
Fragment fragment = Fragment.instantiate(mActivity, SimpleFragment.class.getName(), args);
ft.add(android.R.id.content, fragment, tab.getText().toString());
tab.setTag(obj = fragment);
}
ft.attach((Fragment)obj);
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if( null != mActivity.getFragmentManager().findFragmentByTag(tab.getText().toString()) ){
ft.detach((Fragment)tab.getTag());
}
}
}
public static final class SimpleFragment extends Fragment {
public static final String EXTRA_OUTPUT_MESSAGE = "output_message";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View fragmentView = inflater.inflate(R.layout.fragment_simple, container, false);
String outputMesasge = null;
if( null != getArguments() ){
outputMesasge = getArguments().getString(EXTRA_OUTPUT_MESSAGE);
}
if( null == outputMesasge || 0 == outputMesasge.trim().length() ){
outputMesasge = getString(R.string.demo_text);
}
TextView textView = (TextView) fragmentView.findViewById(R.id.textView_simpleFragmentOutput);
textView.setText(outputMesasge);
return fragmentView;
}
}
}
我可以使用 (values-v14/classes.xml) 和以下代码制作兼容版本
try {
Class<?> clazz = Class.forName(getString(R.string.class_navigationTabsAndFragmentsActivity));
startActivity(clazz);
} catch (ClassNotFoundException ex) {
showTextByToast(ex.getMessage());
}
但我仍然想知道support library版本中发生了什么，有人可以帮我解决这个问题吗？
