为 PreferenceFragmentCompat 安装支持库
Installing a support library for PreferenceFragmentCompat
我是 Android Studio 的新手,总体来说是 Android 编程的新手。我看了又看,找不到合适的事情做。
我只想安装一个库以使用 PreferenceFragmentCompat 或任何 class 替换 android.app.PreferenceFragment所以我的应用程序可以在 API 11 及更低版本中运行。
任何人都可以给我一些详细信息,例如我应该使用哪个库以及如何在我的 AS 项目中安装它。
编辑: 所以我开始使用 android.support.v4
和 android.support.v7
库来开发这个应用程序来处理片段,这样我就可以 运行 API 11 岁及以下。
这是我的MainActivity.java.
package com.example.myapplication;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
@Override
public void onNavigationDrawerItemSelected(int position) {
Fragment mainFragment = null;
switch(position) {
case 0: // home fragment
mainFragment = new HomeFragment();
break;
case 1: // favorites list
mainFragment = new FaveFragment();
break;
case 2: // rate app
/* visit app TODO put application package id in the link */
Intent visitStore = new Intent(Intent.ACTION_VIEW);
visitStore.setData(Uri.parse("market://details?id=com.google.android.apps.maps"));
startActivity(visitStore);
break;
case 3: // settings
mainFragment = new SettingsFragment();
break;
case 4: // about
mainFragment = new AboutFragment();
break;
}
if(position != 2) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, mainFragment)
.commit();
}
}
public void onSectionAttached(int number) {
String[] stringArray = getResources().getStringArray(R.array.section_titles);
if (number >= 1) {
mTitle = stringArray[number - 1];
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
现在这是我的 SettingsFragment.java:
package com.example.myapplication;
import android.os.Bundle;
import android.preference.PreferenceFragment;
public class SettingsFragment extends PreferenceFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
}
我在这里遇到的真正问题是这一行:mainFragment = new SettingsFragment();
在 MainActivity.java 的 onNavigationDrawerItemSelected(int position)
方法中。
它 returns 一个错误说:
Error:(70, 32) error: incompatible types: SettingsFragment cannot be
converted to Fragment
如何解决此问题并仍然能够在 API 11 及更低版本上使用我的应用程序?
将 com.android.support:preference-v7:23.0.1
添加到 build.gradle 文件后,只需更改行
对于 AndroidX:androidx.preference:preference:1.0.0
public class SettingsFragment extends PreferenceFragment {
到
public class SettingsFragment extends PreferenceFragmentCompat {
错误是由 PreferenceFragment
引起的,它扩展了 android.app.Fragment
,而不是您需要的 android.support.v4.app.Fragment
,因为您正在使用支持库 class。
对于任何使用 androidx
的人,请将其添加到您的依赖项中
dependencies {
...
implementation 'androidx.preference:preference:{your_version}'
// example: implementation 'androidx.preference:preference:1.1.1'
}
我是 Android Studio 的新手,总体来说是 Android 编程的新手。我看了又看,找不到合适的事情做。
我只想安装一个库以使用 PreferenceFragmentCompat 或任何 class 替换 android.app.PreferenceFragment所以我的应用程序可以在 API 11 及更低版本中运行。
任何人都可以给我一些详细信息,例如我应该使用哪个库以及如何在我的 AS 项目中安装它。
编辑: 所以我开始使用 android.support.v4
和 android.support.v7
库来开发这个应用程序来处理片段,这样我就可以 运行 API 11 岁及以下。
这是我的MainActivity.java.
package com.example.myapplication;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
@Override
public void onNavigationDrawerItemSelected(int position) {
Fragment mainFragment = null;
switch(position) {
case 0: // home fragment
mainFragment = new HomeFragment();
break;
case 1: // favorites list
mainFragment = new FaveFragment();
break;
case 2: // rate app
/* visit app TODO put application package id in the link */
Intent visitStore = new Intent(Intent.ACTION_VIEW);
visitStore.setData(Uri.parse("market://details?id=com.google.android.apps.maps"));
startActivity(visitStore);
break;
case 3: // settings
mainFragment = new SettingsFragment();
break;
case 4: // about
mainFragment = new AboutFragment();
break;
}
if(position != 2) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, mainFragment)
.commit();
}
}
public void onSectionAttached(int number) {
String[] stringArray = getResources().getStringArray(R.array.section_titles);
if (number >= 1) {
mTitle = stringArray[number - 1];
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
现在这是我的 SettingsFragment.java:
package com.example.myapplication;
import android.os.Bundle;
import android.preference.PreferenceFragment;
public class SettingsFragment extends PreferenceFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
}
我在这里遇到的真正问题是这一行:mainFragment = new SettingsFragment();
在 MainActivity.java 的 onNavigationDrawerItemSelected(int position)
方法中。
它 returns 一个错误说:
Error:(70, 32) error: incompatible types: SettingsFragment cannot be converted to Fragment
如何解决此问题并仍然能够在 API 11 及更低版本上使用我的应用程序?
将 com.android.support:preference-v7:23.0.1
添加到 build.gradle 文件后,只需更改行
对于 AndroidX:androidx.preference:preference:1.0.0
public class SettingsFragment extends PreferenceFragment {
到
public class SettingsFragment extends PreferenceFragmentCompat {
错误是由 PreferenceFragment
引起的,它扩展了 android.app.Fragment
,而不是您需要的 android.support.v4.app.Fragment
,因为您正在使用支持库 class。
对于任何使用 androidx
的人,请将其添加到您的依赖项中
dependencies {
...
implementation 'androidx.preference:preference:{your_version}'
// example: implementation 'androidx.preference:preference:1.1.1'
}