我最近再次开始为android编程,目前正在开发一款应用程序,我想实现水平视图寻呼机,这样用户在一个实例中可以在两个页面之间滑动以输入/更新信息,在稍后的实例中,用户可以在四个页面之间滚动以查看他们输入/更新的信息。我基本上是在为角色扮演游戏制作电子角色表。
我一直在为水平视图寻呼机编写这些教程:http://mobile.tutsplus.com/tutorials/android/android-user-interface-design-horizontal-view-paging/
http://manishkpr.webheavens.com/android-viewpager-example/
我的问题是,在我看过的所有教程中,h.视图寻呼机是在主活动屏幕之外使用的,有没有办法在后续屏幕之外实现水平视图寻呼机?每次我试图实现代码在主屏幕以外的页面上工作时,我一到那个页面就崩溃了。
长话短说,有人成功地在非主页上实现了水平视图寻呼机吗?如果是,如何实现?
我希望我说得有道理,但如果你有任何进一步的问题,请告诉我!
08-24 01:44:34.310:I/ActivityManager(144):从pid 15115启动{cmp=com.echaractersheet/.CharacterStats1}08-24 01:44:34.360:D/AndroidRuntime(15115):关闭VM08-24 01:44:34.360:W/dalvikvm(15115):线程ID=1:线程退出,出现未捕获的异常(组=0x40a581f8)08-24 01:44:34.370:E/AndroidRuntime(15115):致命异常:main08-24 01:44:34.370:E/AndroidRuntime(15115):java.lang.RuntimeException:无法启动活动ComponentInfo{com.echaractersheet/com.echaraactersheet.CharacterStats1}:java.lang.NullPointerException
characterstats.xml:
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/characterstatspager" />
characterstats1.xml和characterstats2.xml是我想在之间滑动的两个页面
CharacterStatsPagerAdapter.java:…
public class CharacterStatsPagerAdapter extends PagerAdapter {
public int getCount() {
return 2;
}
public Object instantiateItem(View collection, int position) {
LayoutInflater inflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
int resId =0;
switch (position) {
case 0:
resId = R.layout.characterstats1;
break;
case 1:
resId = R.layout.characterstats2;
break;
}
View view = inflater.inflate(resId, null);
((ViewPager) collection).addView(view, 0);
return view;
}
@Override
public void destroyItem(View arg0, int arg1, Object arg2) {
((ViewPager) arg0).removeView((View) arg2);
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == ((View) arg1);
}
@Override
public Parcelable saveState() {
return null;
}
}
CharacterStats1.java:
CharacterStatsPagerAdapter adapter = new CharacterStatsPagerAdapter();
ViewPager myPager = (ViewPager) findViewById(R.id.characterstatspager);
myPager.setAdapter(adapter);
myPager.setCurrentItem(0);
好吧,寻呼机将处理适配器中的数据,所以只要您将对象保留在适配器中,就可以使用了。因此,也许在进入下一个屏幕之前,您应该将对象保存在适配器中(也许保存到另一个类中的静态字段中,只需片刻),当您进入新页面时,您可以检索对象并将它们放在新viewpager的适配器中,然后添加新页面。在你的情况下,我会这么做。
更新:
这只是一个例子,这需要更多的代码行,但这是一个良好的开端。
public class Fields {
private String name;
private String lastName;
private int age;
private boolean male;
public Fields(){
this.name = "";
this.lastName = "";
}
public Fields(String name, String lastName, int age, boolean male) {
this.name = name;
this.lastName = lastName;
this.age = age;
this.male = male;
}
public View getRepresentation(Context mContext){
/*Create the view that ViewPager will display*/
LinearLayout layout = new LinearLayout(mContext);
layout.addView(new TextView(mContext)); //Name
layout.addView(new TextView(mContext)); //LastName
layout.addView(new TextView(mContext)); //Age
layout.addView(new CheckBox(mContext)); //Male/Female
return layout;
}
}
视图寻呼机适配器
public class ViewPagerAdapter extends PagerAdapter {
private List<Fields> pages;
private Context mContext;
public ViewPagerAdapter( Context mContext )
{
this.mContext = mContext;
}
public void setPages(List<Fields> pages){
this.pages = pages;
}
public List<Fields> getPages(){
return this.pages;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
@Override
public int getCount()
{
return pages.size();
}
@Override
public Object instantiateItem( View pager, int position )
{
View view = pages.get(position).getRepresentation(mContext);
view.setId(position);
return view;
}
@Override
public void destroyItem( View pager, int position, Object view )
{
((ViewPager)pager).removeViewInLayout( (View) view );
}
@Override
public boolean isViewFromObject( View view, Object object )
{
return view.equals( object );
}
}
主要类别
public class MainActivity extends Activity {
private Context mContext;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.mContext = getApplicationContext();
setContentView(R.layout.viewpager_layout);
final List<Fields> fields = new ArrayList<Fields>();
fields.add(new Fields());
ViewPager mPager = (ViewPager) this.findViewById(R.id.viewpager);
Button nextActivity = (Button) this.findViewById(R.id.nextAct);
ViewPagerAdapter mAdapter = new ViewPagerAdapter(mContext);
mAdapter.setPages(fields);
mPager.setAdapter(mAdapter);
nextActivity.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SecondActivity.pages = fields;
Intent intent = new Intent(mContext, SecondActivity.class);
startActivity(intent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
二级
public class SecondActivity extends Activity {
public static List<Fields> pages;
private Context mContext;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.mContext = getApplicationContext();
setContentView(R.layout.viewpager_layout);
final List<Fields> fields = pages;
pages = null;
fields.add(new Fields()); //Add the new Pages
ViewPager mPager = (ViewPager) this.findViewById(R.id.viewpager);
Button nextActivity = (Button) this.findViewById(R.id.nextAct);
ViewPagerAdapter mAdapter = new ViewPagerAdapter(mContext);
mAdapter.setPages(fields);
mPager.setAdapter(mAdapter);
nextActivity.setVisibility(View.GONE);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
正如我所说,这只是一个例子,应该为对象更改Fields类,ViewPagerAdapter是保存将传递给下一个活动的页面列表的地方。第二个活动上的静态字段只是用作活动和不应该过度使用,这就是为什么在获取数据后需要将其设置为NULL才能知道已经抓住了价值。希望能有所帮助。
注意:此代码将无法正常工作,需要更多代码。