如何在Android中制作一个View隐形 Gone onBackPressed()方法？

概述我在Tabhost中有5个活动.(即MainActivity.javaHome.java,NowReading.java,Favorites.java和Profile.java).在主要活动中,我正在加载tabhost,如下所示.publicclassMainActivityextendsTabActivity{TabHosttabHost;Contextcontext=MainActivity.this;Tex

我在Tabhost中有5个活动. (即MainActivity.java Home.java,NowReading.java,Favorites.java和Profile.java).在主要活动中,我正在加载tabhost,如下所示.

public class MainActivity extends tabactivity {    TabHost tabHost;    Context context = MainActivity.this;    TextVIEw txt_Login;    VIEw hoMetabLayout;    VIEw revIEwLayout;    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_main);        txt_Login = (TextVIEw) findVIEwByID(R.ID.txt_Login);        final Spinner spnrLanguage = (Spinner) findVIEwByID(R.ID.spnrLanguage);        final Spinner spnrbrowseBy = (Spinner) findVIEwByID(R.ID.spnrbrowseBy);        tabHost = getTabHost();        // AndroID tab        Intent intentHome = new Intent().setClass(this, Home.class);        TabSpec tabSpecHome = tabHost                .newTabSpec("Home")                .setIndicator("Home",                        getResources().getDrawable(R.drawable.home))                .setContent(intentHome);        tabHost.addTab(tabSpecHome);        Intent intentNowReading = new Intent().setClass(this, NowReading.class);        TabSpec tabSpecNowReading = tabHost                .newTabSpec("Now Reading")                .setIndicator("Now Reading",                        getResources().getDrawable(R.drawable.Now_reading))                .setContent(intentNowReading);        tabHost.addTab(tabSpecNowReading);        Intent intentFavourite = new Intent().setClass(this, Favorites.class);        TabSpec tabSpecFavourite = tabHost                .newTabSpec("Favourite")                .setIndicator("Favorites",                        getResources().getDrawable(R.drawable.favorites))                .setContent(intentFavourite);        tabHost.addTab(tabSpecFavourite);        Intent intentProfile = new Intent().setClass(this, Profile.class);        TabSpec tabSpecProfile = tabHost                .newTabSpec("Profile")                .setIndicator("Profile",                        getResources().getDrawable(R.drawable.profile))                .setContent(intentProfile);        tabHost.addTab(tabSpecProfile);tabHost.setCurrentTabByTag("Home");

在Mainactivity.java中将Home.java设置为当前Tab.如

tabHost.setCurrentTabByTag("Home");

它在setContentVIEw中加载布局home_activity.xml.

这是XML代码

    <?xml version="1.0" enCoding="utf-8"?><FrameLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"    androID:ID="@+ID/frameLayout01"    androID:layout_wIDth="fill_parent"    androID:layout_height="fill_parent" >    <relativeLayout        androID:ID="@+ID/rel_HomeLayout"        androID:layout_wIDth="match_parent"        androID:layout_height="match_parent" >        <GrIDVIEw            androID:ID="@+ID/grIDvIEw"            androID:layout_wIDth="match_parent"            androID:layout_height="match_parent"            androID:gravity="center"            androID:numColumns="auto_fit"            androID:stretchMode="columnWIDth" >        </GrIDVIEw>    </relativeLayout>    <ScrollVIEw        androID:ID="@+ID/scroll_RevIEwLayout"        androID:layout_wIDth="fill_parent"        androID:layout_height="match_parent" >        <relativeLayout            androID:ID="@+ID/rel_RevIEwLayout01"            androID:layout_wIDth="match_parent"            androID:layout_height="wrap_content" >            <ImageVIEw                androID:ID="@+ID/img_OverVuBookCoverPhoto"                androID:layout_wIDth="130dp"                androID:layout_height="165dp"                androID:layout_margin="5dp"                androID:adjustVIEwBounds="true"                androID:background="@drawable/rounded_image_borders"                androID:paddingleft="5dp"                androID:paddingRight="5dp"                androID:src="@drawable/book1" />            <TextVIEw                androID:ID="@+ID/txt_revwBookTitle"                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_aligntop="@+ID/img_OverVuBookCoverPhoto"                androID:layout_margintop="10dp"                androID:layout_toRightOf="@+ID/img_OverVuBookCoverPhoto"                androID:text="The Basic Doctrine Of Islam"                androID:textcolor="@color/White"                androID:textSize="12sp" />            <TextVIEw                androID:ID="@+ID/txt_revwAuthername"                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_below="@+ID/txt_revwBookTitle"                androID:layout_margintop="2dp"                androID:layout_toRightOf="@+ID/img_OverVuBookCoverPhoto"                androID:text="By: Andrew J Newman"                androID:textcolor="@color/SkyBlue"                androID:textSize="11sp" />            <TextVIEw                androID:ID="@+ID/txt_PublishDate"                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_below="@+ID/txt_revwAuthername"                androID:layout_margintop="2dp"                androID:layout_toRightOf="@+ID/img_OverVuBookCoverPhoto"                androID:text="Published: July, 30 2007"                androID:textcolor="@color/DarkGray"                androID:textSize="11sp" />            <ratingbar                androID:ID="@+ID/ratingbar"                                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_below="@+ID/txt_PublishDate"                androID:layout_marginBottom="6dp"                androID:layout_margintop="6dp"                androID:layout_toRightOf="@+ID/img_OverVuBookCoverPhoto"                androID:isIndicator="false"                androID:numStars="5"                androID:rating="5"                androID:stepSize="1" />            <button                androID:ID="@+ID/btnopenBook"                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_alignBaseline="@+ID/img_OverVuBookCoverPhoto"                androID:layout_below="@+ID/ratingbar"                androID:layout_toRightOf="@+ID/img_OverVuBookCoverPhoto"                androID:text="Open Book"                androID:textcolor="@color/Black"                androID:textSize="13sp" />            <Imagebutton                androID:ID="@+ID/btnBack"                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_alignBottom="@+ID/btnopenBook"                androID:layout_aligntop="@+ID/btnopenBook"                androID:layout_marginleft="5dp"                androID:layout_toRightOf="@+ID/btnopenBook"                androID:src="@drawable/pic_btn_back"                androID:textcolor="@color/Black"                androID:textSize="14sp" />            <TextVIEw                androID:ID="@+ID/txt_BookOvervIEw"                androID:layout_wIDth="wrap_content"                androID:layout_height="wrap_content"                androID:layout_alignleft="@+ID/img_OverVuBookCoverPhoto"                androID:layout_below="@+ID/img_OverVuBookCoverPhoto"                androID:layout_marginBottom="10dp"                androID:layout_margintop="20dp"                androID:text="Book OvervIEw"                androID:textcolor="@color/White"                androID:textSize="13sp" />            <TextVIEw                androID:ID="@+ID/txt_BookOvervIEwDetails"                androID:layout_wIDth="fill_parent"                androID:layout_height="wrap_content"                androID:layout_alignleft="@+ID/img_OverVuBookCoverPhoto"                androID:layout_below="@+ID/txt_BookOvervIEw"                androID:linespacingExtra="4dp"                androID:lines="10"                androID:text="Lorem ipsum dolor sit amet, there was nothing that I can do she was dead, for this reasean I m gonna loose every thing consectetur adipisicing elit, sed do eiusmod tempor incIDIDunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat." >            </TextVIEw>        </relativeLayout>    </ScrollVIEw></FrameLayout>

在Home.java的onCreate方法中,我使Framelayout不可见/ Gone(其中包含了Cliked的概述)

  public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.home_activity);        hoMetabLayout = findVIEwByID(R.ID.rel_HomeLayout);        revIEwLayout = findVIEwByID(R.ID.scroll_RevIEwLayout);        revIEwLayout.setVisibility(VIEw.GONE);

现在,当我单击任何一本书时,它会使我之前在onCreat方法上看不到/看不见的视图可见,如上所述使用代码

grIDVIEw.setonItemClickListener(new OnItemClickListener() {            @OverrIDe            public voID onItemClick(AdapterVIEw<?> arg0, VIEw arg1, int pos,                    long arg3) {                // Todo auto-generated method stub                Toast.makeText(context, BookTitle.get(pos), Toast.LENGTH_SHORT)                        .show();                revIEwLayout.setVisibility(VIEw.VISIBLE);

注意：它不是新的行为,而是我在Click事件上使Visible成为一个视图(即revIEwLayout.setVisibility(VIEw.VISIBLE);).

>我想在onBackpressed()方法上将此视图设为Invisible / Gone.
>我应该在MainActivity.java或Home.java文件中的哪个位置调用此方法？
>如果我在MainActivity.java中调用此方法,则会引发nullPointerException.

解决方法:

你可以覆盖BackPress方法……
借助此功能,您可以隐藏布局或查看…

@OverrIDepublic voID onBackpressed() {     super.onBackpressed();               // Invisible or Gone Your VIEws here....    }

总结

以上是内存溢出为你收集整理的如何在Android中制作一个View隐形/ Gone onBackPressed()方法？全部内容，希望文章能够帮你解决如何在Android中制作一个View隐形/ Gone onBackPressed()方法？所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。